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• Volume 72, Issue 10
• Mental health benefits of interactions with nature in children and teenagers: a systematic review
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• Suzanne Tillmann 1 ,
• Danielle Tobin 1 ,
• William Avison 2 , 3 , 4 , 5 ,
• Jason Gilliland 1 , 3 , 4 , 5 , 6
• 1 Department of Geography , Western University , London , Ontario , Canada
• 2 Department of Sociology , Western University , London , Ontario , Canada
• 3 Department of Epidemiology and Biostatistics , Western University , London , Ontario , Canada
• 4 Children’s Health Research Institute , Lawson Health Research Institute , London , Ontario , Canada
• 5 Department of Paediatrics , Western University , London , Ontario , Canada
• 6 School of Health Studies , Western University , London , Ontario , Canada
• Correspondence to Dr Jason Gilliland, Department of Geography, Western University, London, ON N6A 5K6, Canada; jgillila{at}uwo.ca

Background It is commonly believed that nature has positive impacts on children’s health, including physical, mental and social dimensions. This review focuses on how accessibility to, exposure to and engagement with nature affects the mental health of children and teenagers.

Methods Ten academic databases were used to systematically search and identify primary research papers in English or French from 1990 to 1 March 2017. Papers were included for review based on their incorporation of nature, children and teenagers (0–18 years), quantitative results and focus on mental health.

Results Of the 35 papers included in the review, the majority focused on emotional well-being and attention deficit disorder/hyperactivity disorder. Other outcome measures included overall mental health, self-esteem, stress, resilience, depression and health-related quality of life. About half of all reported findings revealed statistically significant positive relationships between nature and mental health outcomes and almost half reported no statistical significance.

Conclusions Findings support the contention that nature positively influences mental health; however, in most cases, additional research with more rigorous study designs and objective measures of both nature and mental health outcomes are needed to confirm statistically significant relationships. Existing evidence is limited by the cross-sectional nature of most papers.

• child health
• mental health
• environmental health

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/ .

https://doi.org/10.1136/jech-2018-210436

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Introduction

Children’s mental health includes their emotional, psychological and social well-being and affects how they reach developmental milestones, learn healthy social skills, develop sound family and peer relationships, develop a sense of identity and positive self-esteem and learn resilience and coping with stress. 1–7 Mental health issues developed at a young age have the potential to persist into adulthood, continuing the burden on the individual, family, friends and the healthcare system. 8 9 While studies commonly examine individual-level factors (eg, biological, socioeconomic) associated with children’s mental health outcomes, researchers are increasingly recognising the importance of external influences on children’s mental health, such as characteristics of their home, school and neighbourhood environments.

This systematic review considered various forms of children’s and teenagers’ interactions with nature. The evidence to support the connection between nature and children’s mental health is extremely diverse, dispersed and difficult to interpret. Therefore, there is an overwhelming need to critically review and synthesise what evidence currently exists to make appropriate recommendations that can effectively support future research, policy and practice. Previous reviews on the relationship between natural environments and mental health have tended to lump in papers on children with papers on adults. 10–14 Due to the particular objectives and/or inclusion/exclusion criteria of these previous reviews, many relevant (and newer) studies with important findings for children have been overlooked. Likewise, there have been excellent reviews focused on mental health issues among unique subpopulations of youth in specific environments (eg, indigenous youth, Arctic) that have limited generalisability. 15 Other reviews that deal with the benefits of nature for children’s health focus on a variety of other outcomes, such as physical health, rather than mental health. 16–18 The specific objective of this review is to examine the evidence for all children and teenagers (birth to 18 years) to determine how interacting with different types of nature may benefit the mental health of children and teenagers.

The systematic review began with a scoping review to determine appropriate search terms related to nature, mental health and children and teenagers. 19 Search terms were identified by the authors and finalised by an advisory panel of subject experts (see table 1 ). We used 10 bibliographic databases: PubMed, Scopus, PsycINFO, Geobase, ProQuest, SPORTDiscus, Sociological Abstracts, Leisure and Tourism Database, Physical Education Index and EMBASE. Within each database, we screened all English and French papers published 1 January 1990 to 1 March 2017. This period represents approximately one generation in the literature.

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Database search terms

Review process

The review process was divided into three major steps: title screening, abstract screening and document screening. Title screening involved reviewing the outputs from each database search and downloading all titles that appeared relevant into a citation manager (Mendeley V.1.17.10). Of the 227 153 titles screened, 1731 documents were downloaded for further review. Abstracts of all 1731 were then screened and 253 documents were retained which appeared to meet inclusion criteria: Population included children and teenagers 18 years and under, Intervention incorporated an element of nature, Outcome variable included a component of mental health and Study design was quantitative. Finally, the full text of all 253 retained documents was critically assessed using the same inclusion/exclusion criteria as the abstract screening, leaving 35 papers to be included in the systematic review. Finally, reference lists of all 35 papers were inspected for additional relevant citations; however, this search found no new papers (see figure 1 ). The review protocol was registered with PROSPERO (CRD42016046085) and findings reported following PRISMA guidelines.

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Selection process of articles.

Data extraction

Relevant data from the 35 full-text articles were identified and compiled into a data extraction table. This information was used to create a summary of the key characteristics, outcome measurement tools and findings of each study. A meta-analysis was not possible due to the heterogeneity of the methods and principal summary measures reported in the papers.

Assessing bias

Article quality was assessed using study quality assessment tools developed by the National Heart, Lung, and Blood Institute (NHLBI) of the U.S. National Institutes of Health (NIH) Quality Assessment Tools. To assess risk of bias due to study design or implementation, reviewers used one of five NHLBI tools dependent on study design. Two reviewers separately rated each study on a range of items in each tool and then considered the potential flaws (ie, item responses of ‘no’, ‘cannot determine’ and ‘not reported’) to create a scale then used to judge each study and assign an overall ranking of ‘good’, ‘fair’ or ‘poor’ quality. Whenever there was a disagreement between two reviewers, a third reviewer completed the rating and the majority rating was taken. In general, a ‘good’ study has a low risk of bias and results are deemed to be valid, whereas a ‘fair’ study has weaknesses making it susceptible to some bias deemed not sufficient to invalidate its results. A ‘poor’ rating indicates significant risk of bias, meaning results should be interpreted with caution or excluded from the body of evidence.

Of the 35 papers meeting eligibility criteria, 11 were conducted in the USA, 8 in the UK, 2 in Canada and the remaining 14 in other countries. All papers focused on children and teens ranging from 9 months to 18 years of age, with early adolescence being the most commonly studied age group (see table 2 ).

Study characteristics and quality assessment of papers considering nature and mental health of children and teenagers

All of the outcomes studied in the 35 papers were assigned to 1 of 8 categories: emotional well-being (15 papers), attention deficit disorder/hyperactivity disorder (ADD/ADHD) (10 papers), overall mental health (9 papers), self-esteem (9 papers), stress (4 papers), resilience (3 papers), depression (3 papers) and health-related quality of life (HRQOL) (2 papers). Online supplementary table 1 summarises the measurement tools used in each paper, whereas online supplementary table 2 sorts the 35 papers by outcome, with the eight outcomes appearing in order according to number of papers studying that outcome. As some papers examined more than one outcome, the total entries in online supplementary table 2 is more than 35.

Supplementary file 1

Supplementary file 2.

Within the 35 papers, there was substantial diversity with respect to the specific elements of nature under consideration. The elements under study included green space (six papers), water/‘blue’ space (two papers), greenness/greenery (four papers), vegetation (ie, grass, trees) (two papers), gardens (one paper), parks (four papers), outdoor programmes/education (eight papers), wilderness therapy (four papers), forest schools (one paper) and various outdoor/natural settings (ie, schoolyards, green outdoor settings) (nine papers).

There was also considerable variation among the methods researchers used to assess children’s interaction with nature. Despite the heterogeneity, a closer examination of study methods allowed us to group each study into one of three broad categories we define as ‘accessibility’, ‘exposure’ and ‘engagement’ (see table 3 for results based on nature interaction). In simple terms, accessibility refers to the ease of reaching destinations. Accessibility influences the likelihood a child will encounter or interact with nature, but does not necessarily equate to direct contact or interaction. For example, in most studies reviewed here, accessibility measures are passive and opportunity-based and tend to be operationalised in terms of distance/proximity to one or more elements of nature or density/coverage of one or more nature elements within an area around home. On the other hand, exposure can be defined as the condition of being presented to view, having contact with or being subjected to some effect or influence. Exposure, therefore, implies that the child has a direct encounter with nature, rather than mere opportunity. Nevertheless, in most studies reviewed here, exposure is a measure of incidental contact and is operationalised in terms of ‘time spent in/near’ or simply ‘use of’, a natural area such as a park. Engagement refers to involvement or participation in an activity and differs from the other two categories in that it implies an interaction with nature which is more direct, intentional and sustained. For example, the most popular form of engagement described in the studies reviewed here was participation in a wilderness therapy programme for days/weeks.

Findings by outcome, type of nature interaction and study quality

As displayed in table 3 (and online supplementary table 2 ), the 35 papers reported a total of 100 individual findings on the relationship between children’s and teenagers’ mental health and nature. Over half of the findings (53 of 100) confirmed statistically significant positive relationships (ie, positive benefits of nature) (PR), whereas the remaining findings were non-significant (NS). Only one paper reported a single finding suggesting nature had negative effects on children’s mental health (NR).

Emotional well-being

Fifteen papers included emotional well-being as a dependent variable. Emotional well-being was captured through variables such as emotional health, emotional symptoms, emotional intelligence, mood and emotional problems. Within the 15 papers, 12 findings demonstrated a significant positive relationship between nature and emotional well-being, whereas 15 findings were deemed non-significant. After removing two papers rated as poor quality, only 10 out of 23 findings identified a significant positive relationship between nature and emotional well-being.

Attention deficit disorder/hyperactivity disorder (ADD/ADHD)

Ten papers assessed nature interactions and ADD, ADHD or symptoms related to these two disorders (hyperactivity, inattention and attention). Within the 10 papers, there were a total of 19 findings, with 13 exhibiting statistically significant positive results. Nevertheless, six findings came from studies rated poor quality. After removing poor studies, seven out of 13 findings identified a statistically significant positive relationship. Increased accessibility to nature (6/9 significant positive findings) and increased exposure (7/9 significant positive findings) to nature were associated with improvements in ADD/ADHD symptoms.

Overall mental health

Nine papers looked at an overall measure of children’s mental health. Six papers focused on how engagement with nature, through wilderness and adventure programming, can affect overall mental health in teenage children. Overall mental health was assessed through several measures, for example psychological well-being, psychological distress or overall mental health. Eleven out of 18 findings within the 9 papers identified a significant positive relationship with nature. After removing poor findings, 8 out of 12 findings identified a significant positive relationship. One study found a negative association between residential surrounding greenness and overall mental health. 20

Self-esteem

Compared with other outcomes, self-esteem exhibited the most non-significant findings compared with significant positive findings. Nine papers measured the relationship between self-esteem and nature, with most focusing on nature through engagement. Ten out of 13 findings supported a non-significant relationship; no studies were rated poor quality.

Accessibility and engagement to nature were both measured in relationship to stress in four papers. Five out of seven findings found interacting with nature to be significantly positively associated with reduced stress. After removing all poor findings, four out of five findings identified a significant positive relationship.

The majority of findings in the three papers focusing on depression were non-significant, with four of six findings showing no significant relationship with nature, and no studies were rated poor. All three studies measured depressive symptoms through various scales.

All three studies measuring resilience used a form of outdoor programming, or engagement, to assess the relationship to nature. Resilience was subdivided into measures of sense of mastery, relatedness and emotional reactivity. It was found that adventure programmes resulted in an increase in mastery (improved self-efficacy and coping skills) and relatedness (more comfortable interacting with others) and decrease in emotional reactivity (ability to manage emotions when upset). 21 Three out of five findings were found to show significant positive associations between resilience and nature, no studies were rated poor.

Health-related quality of life (HRQOL)

Two papers used HRQOL as a measure of mental health. Of the five findings taken from these papers, four showed a significant positive association with nature, no studies were rated poor. HRQOL takes into account factors influencing mental health including physical, emotional, social, school, family, friends and self-esteem functioning.

Accessibility, exposure, engagement

Engagement was the most commonly used interaction to measure the relationship between children’s and teenagers’ mental health and nature (15 papers); however, there were fewer positive significant findings than non-significant findings for this type of nature interaction (20:24). Fourteen papers measured nature through exposure and 11 through accessibility. The largest gap in the ratio between positive significant and non-significant findings was for exposure to nature (16:9), with accessibility falling between engagement and exposure (17:13).

Geographic differences

There are few geographical patterns among the findings; however, five out of the six studies set outside of North America and Europe dealt with children’s and teenagers’ engagement with nature, whereas the type of interactions studied in North America and Europe were more mixed among accessibility, exposure and engagement. Additionally, studies set in North America were more likely to report positive significant findings than non-significant findings (18:7), distinguishing them from studies in Europe (PR 23:NS 27:NR 1), Australia/New Zealand (PR 9: NS 8), Africa (PR 3: NS 1) and Asia (PR 0: NS 2).

Risk of bias

The quality assessment process revealed 9 good, 19 fair and 7 poor papers. The majority of the findings fell within the papers representing a fair quality assessment. After removing findings from papers rated as ‘poor’, the evidence base contained 41 positive significant findings (previously 52), 41 non-significant results (previously 45), and 1 negative significant finding. This decrease resulted in an equal significant positive results to non-significant results ratio, creating an inconclusive set of findings. Removing poor studies gives a more accurate picture of the relationship between nature and the mental health of children and teens. The majority of findings (12/17) that were removed came from studies researching the association between ADD/ADHD or overall mental health and nature.

This review showed significant positive findings on the benefits of nature for all mental health outcomes; however, ADD/ADHD, overall mental health, stress, resilience and HRQOL were the only outcomes that demonstrated more positive significant findings over non-significant findings. Several outcomes (emotional well-being, self-esteem, depression) were associated with a greater number of non-significant findings than positive significant findings, supporting the inconclusive nature of the evidence reported in previous reviews. 11 12 Furthermore, among all studies only one finding reported a significant negative impact of greenness on a subgroup of children. 20 Clearly additional research is needed, with more rigorous study designs, to confirm the benefits of nature interactions and mental health outcomes.

Framing the types of nature interactions in terms of ‘accessibility’, ‘exposure’ and ‘engagement’ highlighted the distribution of significant positive findings. Among exposure studies, the larger ratio between positive-significant and non-significant findings suggests this type of interaction is the most beneficial and may be the most effective approach for intervention strategies. Among accessibility studies, there was a smaller gap between positive-significant and non-significant findings, potentially due to the fact that accessibility to a particular environment does not equate to use of that environment. Among engagement studies, more findings were non-significant than positive-significant, indicating an inconclusive association between nature engagement and the mental health of children and teens; however, it is noteworthy that the majority of these studies focus on less healthy, ‘at risk’ populations participating in wilderness therapy or outdoor adventure programmes. Further investigation needs to examine how those programmes may benefit general healthy populations.

Studies of emotional well-being, although the most studied outcome, exhibited more non-significant findings than significant-positive findings (14:11). This calls for more rigorous investigations, as emotional well-being is critical for mental health. Findings clearly demonstrate the benefits of nature interaction for decreasing ADD/ADHD symptoms. This has important implications for teachers implementing strategies to help children focus in the classroom. The holistic measure of overall mental health was also most commonly assessed through engagement, finding an overall significant positive relationship; however, there was considerable variation among the tools used by researchers to assess overall mental health. A more universal measure of overall mental health applied to accessibility, exposure and engagement with nature could help to clarify this relationship. The majority of findings related to nature and self-esteem were non-significant; however, most of these studies focused on engagement, suggesting further research should investigate how other types of nature interactions may impact self-esteem. Findings indicate that interacting with nature can help reduce children’s and teenagers’ stress levels; however, these findings are based on a small number of studies and additional research could help confirm the benefits. Finally, for those outcomes with few findings (depression, resilience and HRQOL), it is difficult to interpret a relationship one way or the other. Therefore, more research needs to be conducted to build on potential findings discovered here. All of the findings here suggest that more universal tools should be used to measure both outcomes of mental health as well as nature interactions, in order to more confidently conclude a relationship between the mental health of children and teenagers and nature.

This review supports the application of these findings in various forms of policy, including municipal planning, public health and school board policies. The findings can support policymakers in designing future plans as well as strengthening current policies that take into consideration the importance of natural environments. Furthermore, school boards can use these findings to prioritise school outdoor spaces which are beneficial to the students and to the whole community. By prioritising investments of natural spaces at all levels of government as well as within school districts, children have a better chance of receiving the benefits of interacting with nature.

Strengths and limitations

This systematic review was comprehensive, searching 10 databases resulting in 227 153 titles screened. 19 Having multiple researchers assess abstracts and extract data added methodological rigour. Providing a quality assessment for each paper allows for a more accurate assessment of the weight of the evidence. Additionally, the review focused on children in general rather than a special subgroup of children, allowing the findings to be applicable to a wider population. Finally, conceptualising interactions with nature in terms of accessibility, exposure and engagement was a significant advancement over previous reviews and provides a deeper understanding as to what type, dose and duration of nature is required to influence change in the mental health of children and teenagers.

One limitation relates to the difficulty of scoring study quality. The subjective nature of observational studies does not allow for a clear ‘yes’ or ‘no’ answer to some questions designed for intervention based studies. Furthermore, papers based on qualitative methods were not included in this review due to the difficulties of comparing findings among studies. Their inclusion may have provided for a more fulsome understanding of the benefits of nature for the mental health of children and teenagers. We were unable to complete a meta-analysis with the 35 studies collected due to the heterogeneity of the measures used in each study. The majority of the studies had fairly small sample sizes and were from Europe, North America and other developed regions which can also limit the generalisability of the findings.

Future directions

This review calls for more longitudinal studies to assess the long-term effects that interactions with nature have on mental health, as changes in mental health outcomes cannot always be assessed over a short period. Longitudinal studies would support the assessment of the effects of different doses of nature and potential persistence of effects. The majority of the findings presented here illustrate that nature benefits children’s and teenagers’ mental health. Some contradictory findings, however, highlight the need for greater attention on how nature’s effects differ between populations (ie, toddlers, adolescents). Furthermore, very few studies assessed childhood depression and no studies assessed anxiety, which have more recently come to the attention of public health professionals. Therefore, more research on nature’s connection to these health issues is strongly encouraged. The majority of studies focusing on nature engagement target vulnerable or ‘at risk’ populations, limiting generalisability of findings; future studies should focus on healthy populations to inform change in policy and practice more generally. Likewise, more research is needed in regions outside North American and Europe, especially in less developed nations, to improve generalisability of findings. More rigorous tools are required for measuring nature, nature interactions and mental health outcomes. Indeed, more rigorous measures would allow researchers to more robustly identify associations and causal relationships and to better understand the potential pathways linking nature and positive outcomes for children’s and teenagers’ mental health. 22–24

The primary purpose of this review was to compile and evaluate the existing evidence linking nature and the mental health of children and teenagers. The results demonstrate that interacting with nature is positively associated with the mental health of children and teenagers. The findings, although somewhat inconsistent and often non-significant, demonstrate the need for more in depth and rigorous research. Creating a more standardised measure for operationalising nature is necessary to make these findings generalisable. Understanding why there are differences in the findings is critical to establishing evidence-based recommendations for policy makers and planners in designing neighbourhoods and cities. This review identified the importance in promoting nature interactions to children and teenagers in supporting their mental health.

What is already known on this subject?

Nature has a significant impact on health. Previous reviews have identified the overall health effects of nature on a variety of health outcomes including physical, mental, social and cognitive health.

These reviews have largely highlighted the impact of nature on adult populations, reporting positive effects as well as many inconclusive results.

The current review helps to close gaps in the literature related to the impact of nature on children’s and teenagers’ mental health.

What this study adds

This study critically examines current literature focusing on how nature influences children’s and teenagers’ mental health.

It presents a framework for facilitating comparisons among the heterogeneous body of literature by categorising papers into one of three groups based on type of nature interaction: accessibility, exposure and engagement.

The study highlights the need for more rigorous tools to measure nature interactions.

Additionally, it highlights the growth of research focusing on child populations in the last 5 years.

This study concludes that although the findings vary based on mental health outcome and type of nature interaction, it can be argued that nature does have a beneficial influence on children’s and teenagers’ mental health.

Acknowledgments

We would like to thank the Expert Advisory Panel and Systematic Review Team for their guidance and assistance in the completion of this systematic review.

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Contributors JG devised and supervised the project. All authors made substantial contributions to study design, including development of systematic review procedures. ST and DT conducted the literature search and data extraction and independently assessed the methodological quality of included studies and conducted analysis. JG adjudicated in any disagreements in methodological quality assessments and contributed to analysis. ST, DT and JG drafted the original manuscript and WA critically reviewed the manuscript for important intellectual content. All authors have given approval of this final version to be published and agree to be accountable for all aspects of the work. No others fulfil the criteria for authorship.

Funding This systematic review was made possible through funding from The Lawson Foundation. ST and DT received trainee support from the Children’s Health Research Institute through funding from the Children’s Health Foundation.

Disclaimer The funders were not involved in the design or completion of the review.

Competing interests None declared.

Patient consent Not required.

Provenance and peer review Not commissioned; externally peer reviewed.

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A new, nano-scale look at how the SARS-CoV-2 virus replicates in cells may offer greater precision in drug development, a Stanford University team reports in Nature Communications . Using advanced microscopy techniques, the researchers produced what might be some of the most crisp images available of the virus’s RNA and replication structures, which they witnessed form spherical shapes around the nucleus of the infected cell.

“We have not seen COVID infecting cells at this high resolution and known what we are looking at before,” said Stanley Qi , Stanford associate professor of bioengineering in the Schools of Engineering and of Medicine and co-senior author of the paper. “Being able to know what you are looking at with this high resolution over time is fundamentally helpful to virology and future virus research, including antiviral drug development.”

Blinking RNA 

The work illuminates molecular-scale details of the virus’ activity inside host cells. In order to spread, viruses essentially take over cells and transform them into virus-producing factories, complete with special replication organelles. Within this factory, the viral RNA needs to duplicate itself over and over until enough genetic material is gathered up to move out and infect new cells and start the process over again.

The Stanford scientists sought to reveal this replication step in the sharpest detail to date. To do so, they first labeled the viral RNA and replication-associated proteins with fluorescent molecules of different colors. But imaging glowing RNA alone would result in fuzzy blobs in a conventional microscope. So they added a chemical that temporarily suppresses the fluorescence. The molecules would then blink back on at random times, and only a few lit up at a time. That made it easier to pinpoint the flashes, revealing the locations of the individual molecules.

Using a setup that included lasers, powerful microscopes, and a camera snapping photos every 10 milliseconds, the researchers gathered snapshots of the blinking molecules. When they combined sets of these images, they were able to create finely detailed photos showing the viral RNA and replication structures in the cells. “We have highly sensitive and specific methods and also high resolution,” said Leonid Andronov, co-lead author and Stanford chemistry postdoctoral scholar. “You can see one viral molecule inside the cell.”

The resulting images, with a resolution of 10 nanometers, reveal what might be the most detailed view yet of how the virus replicates itself inside of a cell. The images show magenta RNA forming clumps around the nucleus of the cell, which accumulate into a large repeating pattern. “We are the first to find that viral genomic RNA forms distinct globular structures at high resolution,” said Mengting Han, co-lead author and Stanford bioengineering postdoctoral scholar.

Video showing the different colored fluorescent labels blinking on and off, revealing more precise locations for individual molecules. | Leonid Andronov, Moerner Laboratory

The clusters help show how the virus evades the cell’s defenses, said W. E. Moerner , the paper’s co-senior author and Harry S. Mosher Professor of Chemistry in the School of Humanities and Sciences. “They’re collected together inside a membrane that sequesters them from the rest of the cell, so that they’re not attacked by the rest of the cell.”

Nanoscale drug testing 

Compared to using an electron microscope, the new imaging technique can allow researchers to know with greater certainty where virus components are in a cell thanks to the blinking fluorescent labels. It also can provide nanoscale details of cell processes that are invisible in medical research conducted through biochemical assays. The conventional techniques “are completely different from these spatial recordings of where the objects actually are in the cell, down to this much higher resolution,” said Moerner. “We have an advantage based on the fluorescent labeling because we know where our light is coming from.” 

Seeing exactly how the virus stages its infection holds promise for medicine. Observing how different viruses take over cells may help answer questions such as why some pathogens produce mild symptoms while others are life-threatening. The super-resolution microscopy can also benefit drug development. “This nanoscale structure of the replication organelles can provide some new therapeutic targets for us,” said Han. “We can use this method to screen different drugs and see its influence on the nanoscale structure.”

Indeed, that’s what the team plans to do. They will repeat the experiment and see how the viral structures shift in the presence of drugs like Paxlovid or remdesivir. If a candidate drug can suppress the viral replication step, that suggests the drug is effective at inhibiting the pathogen and making it easier for the host to fight the infection. 

The researchers also plan to map all 29 proteins that make up SARS-CoV-2 and see what those proteins do across the span of an infection. “We hope that we will be prepared to really use these methods for the next challenge to quickly see what’s going on inside and better understand it,” said Qi.

For more information

Acknowledgements: Additional Stanford co-authors include postdoctoral scholar Yanyu Zhu, PhD student Ashwin Balaji, former PhD student Anish Roy, postdoctoral scholar Andrew Barentine, research specialist Puja Patel, and Jaishree Garhyan, director of the In Vitro Biosafety Level-3 Service Center . Moerner is also a member of Stanford Bio-X and the Wu Tsai Neurosciences Institute, and a faculty fellow of Sarafan ChEM-H . Qi is also a member of Bio-X, the Cardiovascular Institute , the Maternal & Child Health Research Institute (MCHRI), the Stanford Cancer Institute, and the Wu Tsai Neurosciences Institute, an institute scholar at Sarafan ChEM-H , and a Chan Zuckerberg Biohub – San Francisco Investigator.

This research was funded by the National Institute of General Medical Sciences of the National Institutes of Health. We also acknowledge use of the Stanford University Cell Sciences Imaging Core Facility.

Taylor Kubota, Stanford University: [email protected]

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Home / Healthy Aging / The mental health benefits of nature: Spending time outdoors to refresh your mind

The mental health benefits of nature: Spending time outdoors to refresh your mind

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Like many others at the height of COVID-19 lockdowns, I was suddenly working remotely, socially distancing from family and friends, and leaving the house only for trips to the grocery store. I craved the ability to get out and escape the overbearing presence screens had in my life.

That ‘ s when I discovered my love of camping. Weekend camping trips let me take advantage of the gorgeous freshwater springs, trails and nature preserves in my area.

I felt the difference almost immediately — out in the woods I wasn’t scrambling for my phone or thinking about work deadlines. My attention span seemed to lengthen and level out. I relaxed. I came home feeling rested and a little more cheerful, and these trips became a way to manage the stress of the pandemic.

Aside from a nice weekend getaway, what I was actually experiencing were the benefits of nature on my mental health — something researchers and healthcare providers have long noted.

“There are many studies that demonstrate how spending time in nature can improve mood, lower anxiety, and improve cognition and memory,” says Mayo Clinic nurse practitioner Jodie M. Smith, APRN., C.N.P., D.N.P., M.S.N. “Making time for nature is important in order for us to maintain resiliency and promote self-care in a world that demands a lot from us.”

Below, Smith discusses exactly why nature is so good for your mental health.

How does nature benefit mental health?

First and foremost, Smith says that nature can be an effective tool to manage stress .

“Stress stimulates our sympathetic nervous system , which is responsible for increasing our blood pressure, heart rate and blood sugar in order to react to a stimulus that is causing us stress,” says Smith.

And while not all stress is bad — for example, stress can motivate you to meet a work deadline or keep an eye on your kids at the pool — prolonged or chronic exposure to stress can chip away at your emotional and mental well-being.

But nature may be able to combat stress and its effects. For example, one study showed that exposure to nature can regulate the sympathetic nervous system in as little as five minutes.

“This means that we can get an almost immediate benefit from stepping outside,” says Smith. And doing so on a recurrent basis may prevent cumulative effects from stress, which could mean a lower risk for chronic disease, illness and mortality .”

In addition to alleviating stress, Smith says research indicates that exposure to nature can be an effective coping strategy for those with chronic mental health conditions, including depression, anxiety, post-traumatic stress disorder (PTSD) and attention-deficit/hyperactivity disorder (ADHD) .

Prolonged immersion in nature and nature-based therapy programs have shown promise as a way of managing PTSD.

Even for those without serious mental health conditions, nature may help you manage emotions like loneliness , irritability and possibly even road rage .

Finally, there is evidence that nature exposure is associated with better cognitive function — like memory, attention, creativity and sleep quality .

But perhaps the best part is that nature makes it easy to soak in these benefits.

“Being present in nature doesn’t ask or require anything of us, so it frees up our mind to think more deeply and clearly about things,” says Smith.

Next time you’re outside, take a moment to listen, touch, smell. Notice the environment around you and simply be present.

What if I live in the city without much nature around?

According to the World Health Organization (WHO), over 55% of people live in urban areas — a number that is expected to rise to 68% by 2050. Increasing urbanization can bring unique health challenges, as WHO estimates that the majority of city-dwellers experience inadequate housing, transportation, sanitation and waste management, as well as low air quality. Combined with the lack of green space in many cities — or open, often walkable areas with plants, natural landscape and water — accessing nature isn’t always as simple as just going outside.

“Cities can be very energetic and exciting but also can contribute to both conscious and unconscious stress from the sensory overload and challenges of maneuvering in those spaces,” says Smith. “If you live in an urban environment, exploring to find even a small natural reprieve can be extremely beneficial.”

If you are unable to fully immerse yourself in nature — like by taking a weekend camping trip — you can still carve out opportunities in your area. This might look like finding a small park near your workplace, taking a moment to sit under a large tree, or taking the time to find a pond or body of water.

“Taking a purposeful five-minute break during the day to refresh your mind in this type of environment can provide a benefit and can be justified by knowing that we will feel better and more productive afterward,” says Smith.

Technology, too, represents a significant distraction — and barrier — to quality time outside and unplugged. Texts, email and social media require a lot of attention , which can take you out of the moment. Instead, Smith recommends leaving your phone behind when seeking green space.

“Slow down, go outside, notice what’s around you,” says Smith. “Listen to the birds and the wind and the crackling of the leaves under your feet, and you really will notice a benefit in your well-being.”

How can I interact with nature if I’m stuck inside all day?

In addition to simply spending more time outdoors, there are several strategies to get more green space into your daily life.

First, consider how you can enjoy nature even if you’re stuck inside. Although it’s not a replacement for fully immersive, outdoor green space, you can still engage your senses by listening to recorded bird songs or a rainstorm instead of music, bringing lush plants into your home and office, decorating with pictures of natural beauty, or using a diffuser with natural scents.

“(These strategies) can improve relaxation and work satisfaction through the same mechanisms that being outdoors can provide,” says Smith.

On a wider scale, you may consider working with your neighbors to plan a community garden, joining or coordinating a walking or bird watching club, and advocating for high-quality parks and environmental centers in your town or city.

How much nature do I need?

Some research suggests that even very quick visits outdoors can be beneficial. But there are indications that certain amounts and types of outdoor time may have greater impacts on well-being. A 2021 study , for example, found that the 20- to 90-minute sessions in nature were most beneficial for mental health, with gardening, nature-based therapy and exercise in green spaces being the most effective for adults.

One large survey found that people who spent at least two hours a week in nature — whether in one longer outing or in multiple smaller chunks of time — were more likely to positively describe their health and well-being than were people who spent no time in nature. If that seems unattainable, Smith recommends that you aim for 15 minutes each day.

“There are added benefits that can come from prolonged immersion, so each week try to spend an hour outside doing something you enjoy, and each month try to spend a half day [outside],” says Smith.

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Brain development and the nature versus nurture debate

Affiliation.

• 1 Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA. [email protected]
• PMID: 21489380
• DOI: 10.1016/B978-0-444-53884-0.00015-4

Over the past three decades, developmental neurobiologists have made tremendous progress in defining basic principles of brain development. This work has changed the way we think about how brains develop. Thirty years ago, the dominant model was strongly deterministic. The relationship between brain and behavioral development was viewed as unidirectional; that is, brain maturation enables behavioral development. The advent of modern neurobiological methods has provided overwhelming evidence that it is the interaction of genetic factors and the experience of the individual that guides and supports brain development. Brains do not develop normally in the absence of critical genetic signaling, and they do not develop normally in the absence of essential environmental input. The fundamental facts about brain development should be of critical importance to neuropsychologists trying to understand the relationship between brain and behavioral development. However, the underlying assumptions of most contemporary psychological models reflect largely outdated ideas about how the biological system develops and what it means for something to be innate. Thus, contemporary models of brain development challenge the foundational constructs of the nature versus nurture formulation in psychology. The key to understanding the origins and emergence of both the brain and behavior lies in understanding how inherited and environmental factors are engaged in the dynamic and interactive processes that define and guide development of the neurobehavioral system.

Copyright © 2011 Elsevier B.V. All rights reserved.

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Article contents

Nature and nurture as an enduring tension in the history of psychology.

• Hunter Honeycutt Hunter Honeycutt Bridgewater College, Department of Psychology
• https://doi.org/10.1093/acrefore/9780190236557.013.518
• Published online: 30 September 2019

Nature–nurture is a dichotomous way of thinking about the origins of human (and animal) behavior and development, where “nature” refers to native, inborn, causal factors that function independently of, or prior to, the experiences (“nurture”) of the organism. In psychology during the 19th century, nature-nurture debates were voiced in the language of instinct versus learning. In the first decades of the 20th century, it was widely assumed that that humans and animals entered the world with a fixed set of inborn instincts. But in the 1920s and again in the 1950s, the validity of instinct as a scientific construct was challenged on conceptual and empirical grounds. As a result, most psychologists abandoned using the term instinct but they did not abandon the validity of distinguishing between nature versus nurture. In place of instinct, many psychologists made a semantic shift to using terms like innate knowledge, biological maturation, and/or hereditary/genetic effects on development, all of which extend well into the 21st century. Still, for some psychologists, the earlier critiques of the instinct concept remain just as relevant to these more modern usages.

The tension in nature-nurture debates is commonly eased by claiming that explanations of behavior must involve reference to both nature-based and nurture-based causes. However, for some psychologists there is a growing pressure to see the nature–nurture dichotomy as oversimplifying the development of behavior patterns. The division is seen as both arbitrary and counterproductive. Rather than treat nature and nurture as separable causal factors operating on development, they treat nature-nurture as a distinction between product (nature) versus process (nurture). Thus there has been a longstanding tension about how to define, separate, and balance the effects of nature and nurture.

• nature–nurture
• development
• nativism–empiricism
• innate–learned
• behavioral genetics
• epigenetics

Nature and Nurture in Development

The oldest and most persistent ways to frame explanations about the behavioral and mental development of individuals is to distinguish between two separate sources of developmental causation: (a) intrinsic, preformed, or predetermined causes (“nature”) versus (b) extrinsic, experiential, or environmental causes (“nurture”). Inputs from these two sources are thought to add their own contribution to development (see Figure 1 ).

Figure 1. The traditional view of nature and nurture as separate causes of development. In the traditional view, nature and nurture are treated as independent causal influences that combine during development to generate outcomes. Note that, during development, the effects of nature and nurture (shown in horizontal crossing lines) remain independent so that their effects on outcomes are theoretically separable.

Because some traits seem to derive more from one source than the other, much of the tension associated with the nature–nurture division deals with disagreements about how to balance the roles of nature and nurture in the development of a trait.

Evidence of Nature in Development

Evidence to support the nature–nurture division usually derives from patterns of behavior that suggest a limited role of environmental causation, thus implying some effect of nature by default. Table 1 depicts some common descriptors and conditions used to infer that some preference, knowledge, or skill is nature based.

Table 1. Common Descriptors and Associated Conditions for Inferring the Effects of Nature on Development

It is important to reiterate that nature-based causation (e.g., genetic determination) is inferred from these observations. Such inferences can generate tension because each of the observations listed here can be explained by nurture-based (environmental) factors. Confusion can also arise when evidence of one descriptor (e.g., being hereditary) is erroneously used to justify a different usage (e.g., that the trait is unlearned).

The Origins of Nature Versus Nurture

For much of recorded history, the distinction between nature and nurture was a temporal divide between what a person is innately endowed with at birth, prior to experience (nature), and what happens thereafter (nurture). It was not until the 19th century that the temporal division was transformed into a material division of causal influences (Keller, 2010 ). New views about heredity and Darwinian evolution justified distinguishing between native traits and genetic causes from acquired traits and environmental causes. More so than before, the terms nature and nurture were often juxtaposed in an opposition famously described by Sir Francis Galton ( 1869 ) as that between “nature versus nurture.”

Galton began writing about heredity in the mid-1860s. He believed we would discover laws governing the transmission of mental as well as physical qualities. Galton’s take on mental heredity, however, was forged by his desire to improve the human race in a science he would later call “eugenics.” In the mid- 19th century , British liberals assumed humans were equivalent at birth. Their social reform efforts were geared to enhancing educational opportunities and improving living conditions. Galton, a political conservative, opposed the notion of natural equality, arguing instead that people were inherently different at birth (Cowan, 2016 ), and that these inherited mental and behavioral inequalities were transmitted through lineages like physical qualities. Because Galton opposed the widely held Lamarckian idea that the qualities acquired in one’s lifetime could modify the inherited potential of subsequent generations, he believed long-lasting improvement of the human stock would only come by controlling breeding practices.

To explain the biological mechanisms of inheritance, Galton joined a growing trend in the 1870s to understand inheritance as involving the transmission of (hypothetical) determinative, germinal substances across generations. Foreshadowing a view that would later become scientific orthodoxy, Galton believed these germinal substances to be uninfluenced by the experiences of the organism. His theory of inheritance, however, was speculative. Realizing he was not equipped to fully explicate his theory of biological inheritance, Galton abandoned this line of inquiry by the end of that decade and refocused his efforts on identifying statistical laws of heredity of individual differences (Renwick, 2011 ).

Historians generally agree that Galton was the first to treat nature (as heredity) and nurture (everything else) as separate causal forces (Keller, 2010 ), but the schism gained biological legitimacy through the work of the German cytologist Auguste Weismann in the 1880s. Whereas Galton’s theory was motivated by his political agenda, Weismann was motivated by a scientific, theoretical agenda. Namely, Weismann opposed Lamarckian inheritance and promoted a view of evolution driven almost entirely by natural selection.

Drawing upon contemporary cytological and embryological research, Weismann made the case that the determinative substances found in the germ cells of plants and animals (called the “germ-plasm”) that are transmitted across generations were physically sequestered very early in embryogenesis and remained buffered from the other cells of the body (“somato-plasm”). This so-called, Weismann’s barrier meant that alterations in the soma that develop in the lifetime of the organism through the use or disuse of body parts would not affect the germinal substances transmitted during reproduction (see Winther, 2001 , for review). On this view, Lamarckian-style inheritance of acquired characteristics was not biologically possible.

Galton and Weismann’s influence on the life sciences cannot be overstated. Their work convinced many to draw unusually sharp distinctions between the inherited (nature) and the acquired (nurture). Although their theories were met with much resistance and generated significant tension in the life sciences from cytology to psychology, their efforts helped stage a new epistemic space through which to appreciate Mendel’s soon to be rediscovered breeding studies and usher in genetics (Muller-Wille & Rheinberger, 2012 ).

Ever since, psychology has teetered between nature-biased and nurture-biased positions. With the rise of genetics, the wedge between nature–nurture was deepened in the early to mid- 20th century , creating fields of study that focused exclusively on the effects of either nature or nurture.

The “Middle Ground” Perspective on Nature–Nurture

Twenty-first-century psychology textbooks often state that the nature–nurture debates have been resolved, and the tension relaxed, because we have moved on from emphasizing nature or nurture to appreciating that development necessarily involves both nature and nurture. In this middle-ground position, one asks how nature and nurture interact. For example, how do biological (or genetic) predispositions for behaviors or innate knowledge bias early learning experiences? Or how might environmental factors influence the biologically determined (maturational) unfolding of bodily form and behaviors?

Rejection of the Nature–Nurture Divide

For some, the “middle-ground” resolution is as problematic as “either/or” views and does not resolve a deeper source of tension inherent in the dichotomy. On this view, the nature–nurture divide is neither a legitimate nor a constructive way of thinking about development. Instead, developmental analysis reveals that the terms commonly associated with nature (e.g., innate, genetic, hereditary, or instinctual) and nurture (environmental or learned) are so entwined and confounded (and often arbitrary) that their independent effects cannot be meaningfully discussed. The nature–nurture division oversimplifies developmental processes, takes too much for granted, and ultimately hinders scientific progress. Thus not only is there a lingering tension about how to balance the effects of nature and nurture in the middle-ground view, but there is also a growing tension to move beyond the dichotomous nature–nurture framework.

Nativism in Behavior: Instincts

Definitions of instinct can vary tremendously, but many contrast (a) instinct with reason (or intellect, thought, will), which is related to but separable from contrasting (b) instinct with learning (or experience or habit).

Instinct in the Age of Enlightenment

Early usages of the instinct concept, following Aristotle, treated instinct as a mental, estimative faculty ( vis aestimativa or aestimativa naturalis ) in humans and animals that allowed for the judgments of objects in the world (e.g., seeing a predator) to be deemed beneficial or harmful in a way that transcends immediate sensory experience but does not involve the use of reason (Diamond, 1971 ). In many of the early usages, the “natural instinct” of animals even included subrational forms of learning.

The modern usage of instincts as unlearned behaviors took shape in the 17th century . By that point it was widely believed that nature or God had implanted in animals and humans innate behaviors and predispositions (“instincts”) to promote the survival of the individual and the propagation of the species. Disagreements arose as to whether instincts derived from innate mental images or were mindlessly and mechanically (physiologically) generated from innately specified bodily organization (Richards, 1987 ).

Anti-Instinct Movement in the Age of Enlightenment

Challenges to the instinct concept can be found in the 16th century (see Diamond, 1971 ), but they were most fully developed by empiricist philosophers of the French Sensationalist tradition in the 18th century (Richards, 1987 ). Sensationalists asserted that animals behaved rationally and all of the so-called instincts displayed by animals could be seen as intelligently acquired habits.

For Sensationalists, instincts, as traditionally understood, did not exist. Species-specificity in behavior patterns could be explained by commonalities in physiological organization, needs, and environmental conditions. Even those instinctual behaviors seen at birth (e.g., that newly hatched chicks peck and eat grain) might eventually be explained by the animal’s prenatal experiences. Erasmus Darwin ( 1731–1802 ), for example, speculated that the movements and swallowing experiences in ovo could account for the pecking and eating of grain by young chicks. The anti-instinct sentiment was clearly expressed by the Sensationalist Jean Antoine Guer ( 1713–1764 ), who warned that instinct was an “infantile idea” that could only be held by those who are ignorant of philosophy, that traditional appeals to instincts in animals not only explained nothing but served to hinder scientific explanations, and that nothing could be more superficial than to explain behavior than appealing to so-called instincts (Richards, 1987 ).

The traditional instinct concept survived. For most people, the complex, adaptive, species-specific behaviors displayed by naïve animals (e.g., caterpillars building cocoons; infant suckling behaviors) appeared to be predetermined and unlearned. Arguably as important, however, was the resistance to the theological implications of Sensationalist philosophy.

One of the strongest reactions to Sensationalism was put forward in Germany by Herman Samuel Reimarus ( 1694–1768 ). As a natural theologian, Reimarus, sought evidence of a God in the natural world, and the species-specific, complex, and adaptive instincts of animals seemed to stand as the best evidence of God’s work. More so than any other, Reimarus extensively catalogued instincts in humans and animals. Rather than treat instincts as behaviors, he defined instincts as natural impulses (inner drives) to act that were expressed perfectly, without reflection or practice, and served adaptive goals (Richards, 1987 ). He even proposed instincts for learning, a proposal that would resurface in the mid- 20th century , as would his drive theory of instinct (Jaynes & Woodward, 1974 ).

Partly as a result of Reimarus’ efforts, the instinct concept survived going into the 19th century . But many issues surrounding the instinct concept were left unsettled. How do instincts differ from reflexive behaviors? What role does learning play in the expression of instincts, if any? Do humans have more or fewer instincts than animals? These questions would persist well into the first decades of the 20th century and ultimately fuel another anti-instinct movement.

Instinct in the 19th Century

In the 19th century , the tension about the nature and nurture of instincts in the lifetime of animals led to debates about the nature and nurture of instincts across generations . These debates dealt with whether instincts should be viewed as “inherited habits” from previous generations or whether they result from the natural selection. Debating the relative roles of neo-Lamarckian use-inheritance versus neo-Darwinian natural selection in the transmutation of species became a significant source of tension in the latter half of the 19th century . Although the neo-Lamarckian notion of instincts as being inherited habits was rejected in the 20th century , it has resurged in recent years (e.g., see Robinson & Barron, 2017 ).

Darwinian evolutionary theory required drawing distinctions between native and acquired behaviors, and, perhaps more so than before, behaviors were categorized along a continuum from the purely instinctive (unlearned), to the partially instinctive (requiring some learning), to the purely learned. Still, it was widely assumed that a purely instinctive response would be modified by experience after its first occurrence. As a result, instinct and habit were very much entangled in the lifetime of the organism. The notion of instincts as fixed and unmodifiable would not be widely advanced until after the rise of Weismann’s germ-plasm theory in the late 19thcentury .

Given their importance in evolutionary theory, there was greater interest in more objectively identifying pure instincts beyond anecdotal reports. Some of the most compelling evidence was reported by Douglas Spalding ( 1844–1877 ) in the early 1870s (see Gray, 1967 ). Spalding documented numerous instances of how naïve animals showed coordinated, seemingly adaptive responses (e.g., hiding) to objects (e.g., sight of predators) upon their first encounter, and he helped pioneer the use of the deprivation experiment to identify instinctive behaviors. This technique involved selectively depriving young animals of seemingly critical learning experiences or sensory stimulation. Should animals display some species-typical action following deprivation, then, presumably, the behavior could be labeled as unlearned or innate. In all, these studies seemed to show that animals displayed numerous adaptive responses at the very start, prior to any relevant experience. In a variety of ways, Spalding’s work anticipated 20th-century studies of innate behavior. Not only would the deprivation experiment be used as the primary means of detecting native tendencies by European zoologists and ethologists, but Spalding also showed evidence of what would later be called imprinting, critical period effects and evidence of behavioral maturation.

Reports of pure instinct did not go unchallenged. Lloyd Morgan ( 1896 ) questioned the accuracy of these reports in his own experimental work with young animals. In some cases, he failed to replicate the results and in other cases he found that instinctive behaviors were not as finely tuned to objects in the environment as had been claimed. Morgan’s research pointed to taking greater precision in identifying learned and instinctive components of behavior, but, like most at the turn of the 20th century , he did not question that animal behavior involved both learned and instinctive elements.

A focus on instinctive behaviors intensified in the 1890s as Weismann’s germ-plasm theory grew in popularity. More so than before, a sharp distinction was drawn between native and acquired characteristics, including behavior (Johnston, 1995 ). Although some psychologists continued to maintain neo-Lamarckian notions, most German (Burnham, 1972 ) and American (Cravens & Burnham, 1971 ) psychologists were quick to adopt Weismann’s theory. They envisioned a new natural science of psychology that would experimentally identify the germinally determined, invariable set of native psychological traits in species and their underlying physiological (neural) basis. However, whereas English-speaking psychologists tended to focus on how this view impacted our understanding of social institutions and its social implications, German psychologists were more interested in the longstanding philosophical implications of Weismann’s doctrine as it related to the differences (if any) between man and beast (Burnham, 1972 ).

Some anthropologists and sociologists, however, interpreted Weismann’s theory quite differently and used it elevate sociology as its own scientific discipline. In the 1890s, the French sociologist Emil Durkheim, for example, interpreted Weismann’s germinal determinants as a generic force on human behavior that influenced the development of general predispositions that are molded by the circumstances of life (Meloni, 2016 ). American anthropologists reached similar conclusions in the early 20th century (Cravens & Burnham, 1971 ). Because Weismann’s theory divorced biological inheritance from social inheritance, and because heredity was treated as a generic force, sociologists felt free to study social (eventually, “cultural”) phenomena without reference to biological or psychological concerns.

Anti-Instinct Movement in the 1920s

Despite their differences, in the first two decades of the 20th century both psychologists and sociologists generally assumed that humans and animals had some native tendencies or instincts. Concerns were even voiced that instinct had not received enough attention in psychology. Disagreements about instincts continued to focus on (the now centuries old debates of) how to conceptualize them. Were they complex reflexes, impulses, or motives to act, or should instinct be a mental faculty (like intuition), separate from reasoning and reflex (Herrnstein, 1972 )?

In America, the instinct concept came under fire following a brief paper in 1919 by Knight Dunlap titled “Are There Any Instincts?” His primary concern dealt with teleological definitions of instincts in which an instinct referred to all the activities involved in obtaining some end-state (e.g., instincts of crying, playing, feeding, reproduction, war, curiosity, or pugnacity). Defined in this way, human instincts were simply labels for human activities, but how these activities were defined was arbitrarily imposed by the researchers. Is feeding, for instance, an instinct, or is it composed of more basic instincts (like chewing and swallowing)? The arbitrariness of classifying human behavior had led to tremendous inconsistencies and confusion among psychologists.

Not all of the challenges to instinct dealt with its teleological usage. Some of the strongest criticisms were voiced by Zing-Yang Kuo throughout the 1920s. Kuo was a Chinese animal psychologist who studied under Charles Tolman at the University of California, Berkeley. Although Kuo’s attacks on instinct changed throughout the 1920s (see Honeycutt, 2011 ), he ultimately argued that all behaviors develop in experience-dependent ways and that appeals to instinct were statements of ignorance about how behaviors develop. Like Dunlap, he warned that instincts were labels with no explanatory value. To illustrate, after returning to China, he showed how the so-called rodent-killing instinct in cats often cited by instinct theorists is not found in kittens that are reared with rodents (Kuo, 1930 ). These kittens, instead, became attached to the rodents, and they resisted attempts to train rodent-killing. Echoing the point made by Guer, Kuo claimed that appeals to instinct served to stunt scientific inquiry into the developmental origins of behavior.

But Kuo did not just challenge the instinct concept. He also argued against labeling behaviors as “learned.” After all, whether an animal “learns” depends on the surrounding environmental conditions, the physiological and developmental status of the animal, and, especially, the developmental (or experiential) history of that animal. Understanding learning also required developmental analysis. Thus Kuo targeted the basic distinction between nature and nurture, and he was not alone in doing so (e.g., see Carmichael, 1925 ), but his call to reject it did not spread to mainstream American psychologists.

By the 1930s, the term instinct had fallen into disrepute in psychology, but experimental psychologists (including behaviorists) remained committed to a separation of native from acquired traits. If anything, the dividing line between native and acquired behaviors became more sharply drawn than before (Logan & Johnston, 2007 ). For some psychologists, instinct was simply rebranded in the less contentious (but still problematic) language of biological drives or motives (Herrnstein, 1972 ). Many other psychologists simply turned to describing native traits as due to “maturation” and/or “heredity” rather than “instinct.”

Fixed Action Patterns

The hereditarian instinct concept received a reboot in Europe in the 1930s with the rise of ethology led by Konrad Lorenz, Niko Tinbergen, and others. Just as animals inherit organs that perform specific functions, ethologists believed animals inherit behaviors that evolved to serve adaptive functions as well. Instincts were described as unlearned (inherited), blind, stereotyped, adaptive, fixed action patterns, impervious to change that are initiated (released) by specific stimuli in the environment.

Ethologists in 1930s and 1940s were united under the banner of innateness. They were increasingly critical of the trend by American psychologists (i.e., behaviorists) to focus on studying on how a limited number of domesticated species (e.g., white rat) responded to training in artificial settings (Burkhardt, 2005 ). Ethologists instead began with rich descriptions of animal behavior in more natural environments along with detailed analyses of the stimulus conditions that released the fixed action patterns. To test whether behavioral components were innate, ethologists relied primarily on the deprivation experiment popularized by Spalding in the 19th century . Using these methods (and others), ethologists identified numerous fascinating examples of instinctive behaviors, which captured mainstream attention.

In the early 1950s, shortly after ethology had gained professional status (Burkhardt, 2005 ), a series of challenges regarding instinct and innateness were put forth by a small cadre of North American behavioral scientists (e.g., T. C. Schneirla, Donald Hebb, Frank Beach). Arguably the most influential critique was voiced by comparative psychologist Daniel Lehrman ( 1953 ), who presented a detailed and damning critique of deprivation experiments on empirical and logical grounds. Lehrman explained that deprivation experiments isolate the animal from some but not all experiences. Thus deprivation experiments simply change what an animal experiences rather than eliminating experience altogether, and so they cannot possibly determine whether a behavior is innate (independent of experience). Instead, these experiments show what environmental conditions do not matter in the development of a behavior but do not speak to what conditions do matter .

Lehrman went on to argue that the whole endeavor to identify instinctive or innate behavior was misguided from the start. All behavior, according to Lehrman, develops from a history of interactions between an organism and its environment. If a behavior is found to develop in the absence of certain experiences, the researcher should not stop and label it as innate. Rather, research should continue to identify the conditions under which the behavior comes about. In line with Kuo, Lehrman repeated the warning that to label something as instinctive (or inherited or maturational) is a statement of ignorance about how that behavior develops and does more to stunt than promote research.

Lehrman’s critique created significant turmoil among ethologists. As a result, ethologists took greater care in using the term innate , and it led to new attempts to synthesize or re-envision learning and instinct .

Some of these attempts focused on an increased role for learning and experience in the ontogeny of species-typical behaviors. These efforts spawned significant cross-talk between ethologists and comparative psychologists to more thoroughly investigate behavioral development under natural conditions. Traditional appeals to instinct and learning (as classical and operant conditioning) were both found to be inadequate for explaining animal behavior. In their stead, these researchers focused more closely on how anatomical, physiological, experiential, and environmental conditions influenced the development of species-typical behaviors.

Tinbergen ( 1963 ) was among those ethologists who urged for greater developmental analysis of species-typical behaviors, and he included it as one of his four problems in the biological study of organisms, along with causation (mechanism), survival value (function), and evolution. Of these four problems, Tinbergen believed ethologists were especially well suited to study survival value, which he felt had been seriously neglected (Burkhardt, 2005 ).

The questions of survival value coupled with models of population genetics would gain significant momentum in the 1960s and 1970s in England and the United States with the rise of behavioral ecology and sociobiology (Griffiths, 2008 ). But because these new fields seemed to promote some kind of genetic determinism in behavioral development, they were met with much resistance and reignited a new round of nature–nurture debates in the 1970s (see Segerstrale, 2000 ).

However, not all ethologists abandoned the instinct concept. Lorenz, in particular, continued to defend the division between nature and nurture. Rather than speaking of native and acquired behaviors, Lorenz later spoke of two different sources of information for behavior (innate/genetic vs. acquired/environmental), which was more a subtle shift in language than it was an actual change in theory, as Lehrman later pointed out.

Some ethologists followed Lorenz’s lead and continued to maintain more of a traditional delineation between instinct and learning. Their alternative synthesis viewed learning as instinctive (Gould & Marler, 1987 ). They proposed that animals have evolved domain-specific “instincts to learn” that result from the its genetic predispositions and innate knowledge. To support the idea of instincts for learning, ethologists pointed to traditional ethological findings (on imprinting and birdsong learning), but they also drew from the growing body of work in experimental psychology that seemed to indicate certain types of biological effects on learning.

Biological Constraints and Preparedness

While ethology was spreading in Europe in the 1930s–1950s, behaviorism reigned in the United States. Just as ethologists were confronted with including a greater role of nurture in their studies, behaviorists were challenged to consider a greater role of nature.

Behaviorists assumed there to be some behavioral innateness (e.g., fixed action patterns, unconditioned reflexes, primary reinforcers and drives). But because behaviorists focused on learning, they tended to study animals in laboratory settings using biologically (or ecologically) irrelevant stimuli and responses to minimize any role of instinct (Johnston, 1981 ). It was widely assumed that these studies would identify general laws of learning that applied to all species regardless of the specific cues, reinforcers, and responses involved.

Challenges to the generality assumption began to accumulate in the 1960s. Some studies pointed to failures that occurred during conditioning procedures. Breland and Breland ( 1961 ), for example, reported that some complex behaviors formed through operant conditioning would eventually become “displaced” by conditioned fixed action patterns in a phenomenon they called “instinctive drift.” Studies of taste-aversion learning (e.g., Garcia & Koelling, 1966 ) also reported the failure of rats to associate certain events (e.g., flavors with shock or audiovisual stimuli with toxicosis).

Other studies were pointing to enhanced learning. In particular, it was found that rats could form strong conditioned taste aversions after only a single pairing between a novel flavor and illness. (This rapid “one trial learning” was a major focus in the research from Niko Tinbergen’s ethological laboratory.) Animals, it seemed, had evolved innate predispositions to form (or not form) certain associations.

In humans, studies of biological constraints on learning were mostly limited to fear conditioning. Evidence indicated that humans conditioned differently to (biologically or evolutionarily) fear-relevant stimuli like pictures of spiders or snakes than to fear-irrelevant stimuli like pictures of mushrooms or flowers (Ohman, Fredrikson, Hugdahl, & Rimmö, 1976 ).

These findings and others were treated as a major problem in learning theory and led to calls for a new framework to study learning from a more biologically oriented perspective that integrated the evolutionary history and innate predispositions of the species. These predispositions were described as biological “constraints” on, “preparedness,” or “adaptive specializations” for learning, all of which were consistent with the “instincts to learn” framework proposed by ethologists.

By the 1980s it was becoming clear that the biological preparedness/constraint view of learning suffered some limitations. For example, what constraints count as “biological” was questioned. It was well established that there were general constraints on learning associated with the intensity, novelty, and timing of stimuli. But, arbitrarily it seemed, these constraints were not classified as “biological” (Domjan & Galef, 1983 ). Other studies of “biological constraints” found that 5- and 10-day old rats readily learned to associated a flavor with shock (unlike in adults), but (like in adults) such conditioning was not found in 15-day-old rats (Hoffman & Spear, 1988 ). In other words, the constraint on learning was not present in young rats but developed later in life, suggesting a possible role of experience in bringing about the adult-like pattern.

Attempts to synthesize these alternatives led to numerous calls for more ecologically oriented approaches to learning not unlike the synthesis between ethology and comparative psychology in the 1960s. All ecological approaches to learning proposed that learning should be studied in the context of “natural” (recurrent and species-typical) problems that animals encounter (and have evolved to encounter) using ecologically meaningful stimuli and responses. Some argued (e.g., Johnston, 1981 ) that studies of learning should take place within the larger context of studying how animals develop and adapt to their surround. Others (Domjan & Galef, 1983 ) pointed to more of a comparative approach in studying animal learning in line with behavioral ecology that takes into account how learning can be influenced by the possible selective pressures faced by each species. Still, how to synthesize biological constraints (and evolutionary explanations) on learning with a general process approach remains a source of tension in experimental psychology.

Nativism in Mind: Innate Ideas

Nativism and empiricism in philosophy.

In the philosophy of mind, nature–nurture debates are voiced as debates between nativists and empiricists. Nativism is a philosophical position that holds that our minds have some innate (a priori to experience) knowledge, concepts, or structure at the very start of life. Empiricism, in contrast, holds that all knowledge derives from our experiences in the world.

However, rarely (if ever) were there pure nativist or empiricist positions, but the positions bespeak a persistent tension. Empiricists tended to eschew innateness and promote a view of the mental content that is built by general mechanisms (e.g., association) operating on sensory experiences, whereas nativists tend to promote a view of mind that contains domain-specific, innate processes and/or content (Simpson, Carruthers, Laurence, & Stich, 2005 ). Although the tension about mental innateness would loosen as empiricism gained prominence in philosophy and science, the strain never went away and would intensify again in the 20th century .

Nativism in 20th Century Psychology: The Case of Language Development

In the first half of the 20th century , psychologists generally assumed that knowledge was gained or constructed through experience with the world. This is not to say that psychologists did not assume some innate knowledge. The Swiss psychologist Jean Piaget, for example, believed infants enter the world with some innate knowledge structures, particularly as they relate to early sensory and motor functioning (see Piaget, 1971 ). But the bulk of his work dealt with the construction of conceptual knowledge as children adapt to their worlds. By and large, there were no research programs in psychology that sought to identify innate factors in human knowledge and cognition until the 1950s (Samet & Zaitchick, 2017 )

An interest in psychological nativism was instigated in large part by Noam Chomsky’s ( 1959 ) critique of B. F. Skinner’s book on language. To explain the complexity of language, he argued, we must view language as the knowledge and application of grammatical rules. He went on to claim that the acquisition of these rules could not be attributed to any general-purpose, learning process (e.g., reinforcement). Indeed, language acquisition occurs despite very little explicit instruction. Moreover, language is special in terms of its complexity, ease, and speed of acquisition by children and in its uniqueness to humans. Instead, he claimed that our minds innately contain some language-specific knowledge that kick-starts and promotes language acquisition. He later claimed this knowledge can be considered some sort of specialized mental faculty or module he called the “language acquisition device” (Chomsky, 1965 ) or what Pinker ( 1995 ) later called the “language instinct.”

To support the idea of linguistic nativism, Chomsky and others appealed to the poverty of the stimulus argument. In short, this argument holds that our experiences in life are insufficient to explain our knowledge and abilities. When applied to language acquisition, this argument holds children’s knowledge of language (grammar) goes far beyond the limited, and sometimes broken, linguistic events that children directly encounter. Additional evidence for nativism drew upon the apparent maturational quality of language development. Despite wide variations in languages and child-rearing practices across the world, the major milestones in language development appear to unfold in children in a universal sequence and timeline, and some evidence suggested a critical period for language acquisition.

Nativist claims about language sparked intense rebuttals by empiricist-minded psychologists and philosophers. Some of these retorts tackled the logical limitations of the poverty of stimulus argument. Others pointed to the importance of learning and social interaction in driving language development, and still others showed that language (grammatical knowledge) may not be uniquely human (see Tomasello, 1995 , for review). Nativists, in due course, provided their own rebuttals to these challenges, creating a persistent tension in psychology.

Extending Nativism Beyond Language Development

In the decades that followed, nativist arguments expanded beyond language to include cognitive domains that dealt with understanding the physical, psychological, and social worlds. Developmental psychologists were finding that infants appeared to be much more knowledgeable in cognitive tasks (e.g., on understanding object permanence) and skillful (e.g., in imitating others) than had previously been thought, and at much younger ages. Infants also showed a variety of perceptual biases (e.g., preference for face-like stimuli over equally complex non-face-like stimuli) from very early on. Following the standard poverty of the stimulus argument, these findings were taken as evidence that infants enter the world with some sort of primitive, innate, representational knowledge (or domain-specific neural mechanisms) that constrains and promotes subsequent cognitive development. The nature of this knowledge (e.g., as theories or as core knowledge), however, continues to be debated (Spelke & Kinzler, 2007 ).

Empiricist-minded developmental psychologists responded by demonstrating shortcomings in the research used to support nativist claims. For example, in studies of infants’ object knowledge, the behavior of infants (looking time) in nativist studies could be attributed to relatively simple perceptual processes rather than to the infants’ conceptual knowledge (Heyes, 2014 ). Likewise, reports of human neonatal imitation not only suffered from failures to replicate but could be explained by simpler mechanisms (e.g., arousal) than true imitation (Jones, 2017 ). Finally, studies of perceptual preferences found in young infants, like newborn preferences for face-like stimuli, may not be specific preferences for faces per se but instead may reflect simpler, nonspecific perceptual biases (e.g., preferences for top-heavy visual configurations and congruency; Simion & Di Giorgio, 2015 ).

Other arguments from empiricist-minded developmental psychologists focused on the larger rationale for inferring innateness. Even if it is conceded that young infants, like two-month-olds, or even two-day-olds, display signs of conceptual knowledge, there is no good evidence to presume the knowledge is innate. Their knowledgeable behaviors could still be seen as resulting from their experiences (many of which may be nonobvious to researchers) leading up to the age of testing (Spencer et al., 2009 ).

In the 21st century , there is still no consensus about the reality, extensiveness, or quality of mental innateness. If there is innate knowledge, can experience add new knowledge or only expand the initial knowledge? Can the doctrine of innate knowledge be falsified? There are no agreed-upon answers to these questions. The recurring arguments for and against mental nativism continue to confound developmental psychologists.

Maturation Theory

The emergence of bodily changes and basic behavioral skills sometimes occurs in an invariant, predictable, and orderly sequence in a species despite wide variations in rearing conditions. These observations are often attributed to the operation of an inferred, internally driven, maturational process. Indeed, 21st-century textbooks in psychology commonly associate “nature” with “maturation,” where maturation is defined as the predetermined unfolding of the individual from a biological or genetic blueprint. Environmental factors play a necessary, but fundamentally supportive, role in the unfolding of form.

Preformationism Versus Epigenesis in the Generation of Form

The embryological generation of bodily form was debated in antiquity but received renewed interest in the 17th century . Following Aristotle, some claimed that embryological development involved “epigenesis,” defined as the successive emergence of form from a formless state. Epigenesists, however, struggled to explain what orchestrated development without appealing to Aristotelean souls. Attempts were made to invoke to natural causes like physical and chemical forces, but, despite their best efforts, the epigenesists were forced to appeal to the power of presumed, quasi-mystical, vitalistic forces (entelechies) that directed development.

The primary alternative to epigenesis was “preformationism,” which held that development involved the growth of pre-existing form from a tiny miniature (homunculus) that formed immediately after conception or was preformed in the egg or sperm. Although it seems reasonable to guess that the invention and widespread use of the microscope would immediately lay to rest any claim of homuncular preformationism, this was not the case. To the contrary, some early microscopists claimed to see signs of miniature organisms in sperm or eggs, and failures to find these miniatures were explained away (e.g., the homunculus was transparent or deflated to the point of being unrecognizable). But as microscopes improved and more detailed observations of embryological development were reported in the late 18th and 19th centuries , homuncular preformationism was finally refuted.

From Preformationism to Predeterminism

Despite the rejection of homuncular preformationism, preformationist appeals can be found throughout the 19th century . One of the most popular preformationist theories of embryological development was put forth by Ernst Haeckel in the 1860s (Gottlieb, 1992 ). He promoted a recapitulation theory (not original to Haeckel) that maintained that the development of the individual embryo passes through all the ancestral forms of its species. Ontogeny was thought to be a rapid, condensed replay of phylogeny. Indeed, for Haeckel, phylogenesis was the mechanical cause of ontogenesis. The phylogenetic evolution of the species created the maturational unfolding of embryonic form. Exactly how this unfolding takes place was less important than its phylogenetic basis.

Most embryologists were not impressed with recapitulation theory. After all, the great embryologist Karl Ernst von Baer ( 1792–1876 ) had refuted strict recapitulation decades earlier. Instead, there was greater interest in how best to explain the mechanical causes of development ushering in a new “experimental embryology.” Many experimental embryologists followed the earlier epigenesists by discussing vitalistic forces operating on the unorganized zygote. But it soon became clear that the zygote was structured, and many people believed the zygote contained special (unknown) substances that specified development. Epigenesis-minded experimental embryologists soon warned that the old homuncular preformationism was being transformed into a new predetermined preformationism.

As a result, the debates between preformationism and epigenesis were reignited in experimental embryology, but the focus of these debates shifted to the various roles of nature and nurture during development. More specifically, research focused on the extent to which early cellular differentiation was predetermined by factors internal to cells like chromosomes or cytoplasm (preformationism, nature) or involved factors (e.g., location) outside of the cell (epigenesis, nurture). The former emphasized reductionism and developmental programming, whereas the latter emphasized some sort of holistic, regulatory system responsive to internal and external conditions. The tension between viewing development as predetermined or “epigenetic” persists into the 21st century .

Preformationism gained momentum in the 20th century following the rediscovery of Mendel’s studies of heredity and the rapid rise of genetics, but not because of embryological research on the causes of early differentiation. Instead, preformationism prevailed because it seemed embryological research on the mechanisms of development could be ignored in studies of hereditary patterns.

The initial split between heredity and development can be found in Galton’s speculations but is usually attributed to Weismann’s germ-plasm theory. Weismann’s barrier seemed to posit that the germinal determinants present at conception would be the same, unaltered determinants transmitted during reproduction. This position, later dubbed as “Weismannism,” was ironically not one promoted by Weismann. Like nearly all theorists in the 19th century , he viewed the origins of variation and heredity as developmental phenomena (Amundson, 2005 ), and he claimed that the germ-plasm could be directly modified in the lifetime of the organism by environmental (e.g., climactic and dietary) conditions (Winther, 2001 ). Still, Weismann’s theory treated development as a largely predetermined affair driven by inherited, germinal determinants buffered from most developmental events. As such, it helped set the stage for a more formal divorce between heredity and development with the rise of Mendelism in the early 20th century .

Mendel’s theory of heredity was exceptional in how it split development from heredity (Amundson, 2005 ). More so than in Weismann’s theory, Mendel’s theory assumed that the internal factors that determine form and are transmitted across generations remain unaltered in the lifetime of the organism. To predict offspring outcomes, one need only know the combination of internal factors present at conception and their dominance relations. Exactly how these internal factors determined form could be disregarded. The laws of hereditary transmission of the internal factors (e.g., segregation) did not depend on the development or experiences of the organism or the experiences the organism’s ancestors. Thus the experimental study of heredity (i.e., breeding) could proceed without reference to ancestral records or embryological concerns (Amundson, 2000 ). By the mid-1920s, the Mendelian factors (now commonly called “genes”) were found to be structurally arranged on chromosomes, and the empirical study of heredity (transmission genetics) was officially divorced from studies of development.

The splitting of heredity and development found in Mendel’s and Weismann’s work met with much resistance. Neo-Lamarckian scientists, especially in the United States (Cook, 1999 ) and France (Loison, 2011 ), sought unsuccessfully to experimentally demonstrate the inheritance of acquired characteristics into the 1930s.

In Germany during the 1920s and 1930s, resistance to Mendelism dealt with the chromosomal view of Mendelian heredity championed by American geneticists who were narrowly focused on studying transmission genetics at the expense of developmental genetics. German biologists, in contrast, were much more interested in the broader roles of genes in development (and evolution). In trying to understand how genes influence development, particularly of traits of interest to embryologists, they found the Mendelian theory to be lacking. In the decades between the world wars, German biologists proposed various expanded views of heredity that included some form of cytoplasmic inheritance (Harwood, 1985 ).

Embryologists resisted the preformationist view of development throughout the early to mid- 20th century , often maintaining no divide between heredity and development, but their objections were overshadowed by genetics and its eventual synthesis with evolutionary theory. Consequently, embryological development was treated by geneticists and evolutionary biologists as a predetermined, maturational process driven by internal, “genetic” factors buffered from environmental influence.

Maturation Theory in Psychology

Maturation theory was applied to behavioral development in the 19th century in the application of Haeckel’s recapitulation theory. Some psychologists believed that the mental growth of children recapitulated the history of the human race (from savage brute to civilized human). With this in mind, many people began to more carefully document child development. Recapitulationist notions were found in the ideas of many notable psychologists in the 19th and early 20th centuries (e.g., G. S. Hall), and, as such, the concept played an important role in the origins of developmental psychology (Koops, 2015 ). But for present purposes what is most important is that children’s mental and behavioral development was thought to unfold via a predetermined, maturational process.

With the growth of genetics, maturational explanations were increasingly invoked to explain nearly all native and hereditary traits. As the instinct concept lost value in the 1920s, maturation theory gained currency, although the shift was largely a matter of semantics. For many psychologists, the language simply shifted from “instinct versus learning” to “maturation versus practice/experience” (Witty & Lehman, 1933 ).

Initial lines of evidence for maturational explanations of behavior were often the same as those that justified instinct and native traits, but new embryological research presented in the mid-1920s converged to show support for strict maturational explanations of behavioral development. In these experiments (see Wyman, 2005 , for review), spanning multiple laboratories, amphibians (salamanders and frogs) were exposed to drugs that acted as anesthetics and/or paralytics throughout the early stages of development, thus reducing sensory experience and/or motor practice. Despite the reduced sensory experiences and being unable to move, these animals showed no delays in the onset of motor development once the drugs wore off.

This maturational account of motor development in amphibians fit well with contemporaneous studies of motor development in humans. The orderly, invariant, and predictable (age-related) sequential appearance of motor skills documented in infants reared under different circumstances (in different countries and across different decades) was seen as strong evidence for a maturational account. Additional evidence was reported by Arnold Gessell and Myrtle McGraw, who independently presented evidence in the 1920s to show that the pace and sequence of motor development in infancy were not altered by special training experiences. Although the theories of these maturation theorists were more sophisticated when applied to cognitive development, their work promoted a view in which development was primarily driven by neural maturation rather than experience (Thelen, 2000 ).

Critical and Sensitive Periods

As the maturation account of behavioral development gained ground, it became clear that environmental input played a more informative role than had previously been thought. Environmental factors were found to either disrupt or induce maturational changes at specific times during development. Embryological research suggested that there were well-delineated time periods of heightened sensitivity in which specific experimental manipulations (e.g., tissue transplantations) could induce irreversible developmental changes, but the same manipulation would have no effect outside of that critical period.

In the 1950s–1960s a flurry of critical period effects were reported in birds and mammals across a range of behaviors including imprinting, attachment, socialization, sensory development, bird song learning, and language development (Michel & Tyler, 2005 ). Even though these findings highlighted an important role of experience in behavioral development, evidence of critical periods was usually taken to imply some rigid form of biological determinism (Oyama, 1979 ).

As additional studies were conducted on critical period effects, it became clear that many of the reported effects were more gradual, variable, experience-dependent, and not necessarily as reversible as was previously assumed. In light of these reports, there was a push in the 1970s (e.g., Connolly, 1972 ) to substitute “sensitive period” for “critical period” to avoid the predeterminist connotations associated with the latter and to better appreciate that these periods simply describe (not explain) certain temporal aspects of behavioral development. As a result, a consensus emerged that behaviors should not be attributed to “time” or “age” but to the developmental history and status of the animal under investigation (Michel & Tyler, 2005 ).

Heredity and Genetics

In the decades leading up to and following the start of the 20th century , it was widely assumed that many psychological traits (not just instincts) were inherited or “due to heredity,” although the underlying mechanisms were unknown. Differences in intelligence, personality, and criminality within and between races and sexes were largely assumed to be hereditary and unalterable by environmental intervention (Gould, 1996 ). The evidence to support these views in humans was often derived from statistical analyses of how various traits tended to run in families. But all too frequently, explanations of data were clouded by pre-existing, hereditarian assumptions.

Human Behavioral Genetics

The statistical study of inherited human (physical, mental, and behavioral) differences was pioneered by Galton ( 1869 ). Although at times Galton wrote that nature and nurture were so intertwined as to be inseparable, he nevertheless devised statistical methods to separate their effects. In the 1860s and 1870s, Galton published reports purporting to show how similarities in intellect (genius, talent, character, and eminence) in European lineages appeared to be a function of degree of relatedness. Galton considered, but dismissed, environmental explanations of his data, leading him to confirm his belief that nature was stronger than nurture.

Galton also introduced the use of twin studies to tease apart the relative impact of nature versus nurture, but the twin method he used was markedly different from later twin studies used by behavioral geneticists. Galton tracked the life history of twins who were judged to be very similar or very dissimilar near birth (i.e., by nature) to test the power of various postnatal environments (nurture) that might make them more or less similar over time. Here again, Galton concluded that nature overpowers nurture.

Similar pedigree (e.g., the Kallikak study; see Zenderland, 2001 ) and twin studies appeared in the early 1900s, but the first adoption study and the modern twin method (which compares monozygotic to dizygotic twin pairs) did not appear until the 1920s (Rende, Plomin, & Vandenberg, 1990 ). These reports led to a flurry of additional work on the inheritance of mental and behavioral traits over the next decade.

Behavioral genetic research peaked in the 1930s but rapidly lost prominence due in large part to its association with the eugenics movement (spearheaded by Galton) but also because of the rise and eventual hegemony of behaviorism and the social sciences in the United States. Behavioral genetics resurged in the 1960s with the rising tide of nativism in psychology, and returned to its 1930s-level prominence in the 1970s (McGue & Gottesman, 2015 ).

The resurgence brought with a new statistical tool: the heritability statistic. The origins of heritability trace back to early attempts to synthesize Mendelian genetics with biometrics by Ronald Fisher and others. This synthesis ushered in a new field of quantitative genetics and it marked a new way of thinking about nature and nurture. The shift was to no longer think about nature and nurture as causes of traits in individuals but as causes of variation in traits between populations of individuals. Eventually, heritability came to refer to the amount of variance in a population sample that could be statistically attributed to genetic variation in that sample. Kinship (especially twin) studies provided seemingly straightforward ways of partitioning variation in population trait attributes into genetic versus environmental sources.

Into the early 21st century , hundreds of behavioral genetic studies of personality, intelligence, and psychopathology were reported. With rare exceptions, these studies converge to argue for a pervasive influence of genetics on human psychological variation.

These studies have also fueled much controversy. Citing in part behavioral genetic research, the educational psychologist Arthur Jensen ( 1969 ) claimed that the differences in intelligence and educational achievement in the United States between black and white students appeared to have a strong genetic basis. He went on to assume that because these racial differences appeared hereditary, they were likely impervious to environmental (educational) intervention. His article fanned the embers of past eugenics practices and ignited fiery responses (e.g., Hirsch, 1975 ). The ensuing debates not only spawned a rethinking of intelligence and how to measure it, but they ushered in a more critical look at the methods and assumptions of behavioral genetics.

Challenges to Behavioral Genetics

Many of the early critiques of behavioral genetics centered on interpreting the heritability statistic commonly calculated in kinship (family, twin, and adoption) studies. Perhaps more so than any other statistic, heritability has been persistently misinterpreted by academics and laypersons alike (Lerner, 2002 ). Contrary to popular belief, heritability tells us nothing about the relative impact of genetic and environmental factors on the development of traits in individuals. It deals with accounting for trait variation between people, not the causes of traits within people. As a result, a high heritability does not indicate anything about the fixity of traits or their imperviousness to environmental influence (contra Jensen), and a low heritability does not indicate an absence of genetic influence on trait development. Worse still, heritability does not even indicate anything about the role of genetics in generating the differences between people.

Other challenges to heritability focused not on its interpretation but on its underlying computational assumptions. Most notably, heritability analyses assume that genetic and environmental contributions to trait differences are independent and additive. The interaction between genetic and environmental factors were dismissed a priori in these analyses. Studies of development, however, show that no factor (genes, hormones, parenting, schooling) operates independently, making it impossible to quantify how much of a given trait in a person is due to any causal factor. Thus heritability analyses are bound to be misleading because they are based on biologically implausible and logically indefensible assumptions about development (Gottlieb, 2003 ).

Aside from heritability, kinship studies have been criticized for not being able to disentangle genetic and environmental effects on variation. It had long been known that that in family (pedigree) studies, environmental and genetic factors are confounded. Twin and adoption studies seemed to provide unique opportunities to statistically disentangle these effects, but these studies are also deeply problematic in assumptions and methodology. There are numerous plausible environmental reasons for why monozygotic twin pairs could resemble each other more than dizygotic twin pairs or why adoptive children might more closely resemble their biological than their adoptive parents (Joseph & Ratner, 2013 ).

A more recent challenge to behavioral genetics came from an unlikely source. Advances in genomic scanning in the 21st century made it possible in a single study to correlate thousands of genetic polymorphisms with variation in the psychological profiles (e.g., intelligence, memory, temperament, psychopathology) of thousands of people. These “genome-wide association” studies seemed to have the power and precision to finally identify genetic contributions to heritability at the level of single nucleotides. Yet, these studies consistently found only very small effects.

The failure to find large effects came to be known as the “missing heritability” problem (Maher, 2008 ). To account for the missing heritability, some behavioral geneticists and molecular biologists asserted that important genetic polymorphisms remain unknown, they may be too rare to detect, and/or that current studies are just not well equipped to handle gene–gene interactions. These studies were also insensitive to epigenetic profiles (see the section on Behavioral Epigenetics), which deal with differences in gene expression. Even when people share genes, they may differ in whether those genes get expressed in their lifetimes.

But genome-wide association studies faced an even more problematic issue: Many of these studies failed to replicate (Lickliter & Honeycutt, 2015 ). For those who viewed heritability analyses as biologically implausible, the small effect sizes and failures to replicate in genome-wide association studies were not that surprising. The search for independent genetic effects was bound to fail, because genes simply do not operate independently during development.

Behavioral Epigenetics

Epigenetics was a term coined in the 1940s by the developmental biologist Conrad Waddington to refer to a new field of study that would examine how genetic factors interact with local environmental conditions to bring about the embryological development of traits. By the end of the 20th century , epigenetics came to refer to the study of how nongenetic, molecular mechanisms physically regulate gene expression patterns in cells and across cell lineages. The most-studied mechanisms involve organic compounds (e.g., methyl-groups) that physically bind to DNA or the surrounding proteins that package DNA. The addition or removal of these compounds can activate or silence gene transcription. Different cell types have different, stable epigenetic markings, and these markings are recreated during cell division so that cells so marked give rise to similar types of cells. Epigenetic changes were known to occur during developmental periods of cellular differentiation (e.g., during embryogenesis), but not until 2004 was it discovered that these changes can occur at other periods in the life, including after birth (Roth, 2013 )

Of interest to psychologists were reports that different behavioral and physiological profiles (e.g., stress reactivity) of animals were associated with different epigenetic patterns in the nervous system (Moore, 2015 ). Furthermore, these different epigenetic patterns could be established or modified by environmental factors (e.g., caregiving practices, training regimes, or environmental enrichment), and, under certain conditions, they remain stable over long periods of time (from infancy to adulthood).

Because epigenetic research investigates the physical interface between genes and environment, it represents an exciting advance in understanding the interaction of nature and nurture. Despite some warnings that the excitement over behavioral epigenetic research may be premature (e.g., Miller, 2010 ), for many psychologists, epigenetics underscores how development involves both nature and nurture.

For others, what is equally exciting is the additional evidence epigenetics provides to show that the genome is an interactive and regulated system. Once viewed as the static director of development buffered from environment influence, the genome is better described as a developing resource of the cell (Moore, 2015 ). More broadly, epigenetics also points to how development is not a genetically (or biologically) predetermined affair. Instead, epigenetics provides additional evidence that development is a probabilistic process, contingent upon factors internal and external to the organism. In this sense, epigenetics is well positioned to help dissolve the nature–nurture dichotomy.

Beyond Nature–Nurture

In the final decades of the 20th century , a position was articulated to move beyond the dichotomous nature–nurture framework. The middle-ground position on nature–nurture did not seem up to the task of explaining the origins of form, and it brought about more confusion than clarity. The back-and-forth (or balanced) pendulum between nature- and nurture-based positions throughout history had only gone in circles. Moving forward would require moving beyond such dichotomous thinking (Johnston, 1987 ).

The anti-dichotomy position, referred to as the Developmentalist tradition, was expressed in a variety of systems-based, metatheoretical approaches to studying development, all of which extended the arguments against nature–nurture expressed earlier by Kuo and Lehrman. The central problem with all nativist claims according to Developmentalists is a reliance on preformationism (or predeterminism).

The problem with preformationism, they argue, besides issues of evidence, is that it is an anti-developmental mindset. It presumes the existence of the very thing(s) one wishes to explain and, consequently, discourages developmental analyses. To claim that some knowledge is innate effectively shuts down research on the developmental origins of that knowledge. After all, why look for the origins of conceptual knowledge if that knowledge is there all along? Or why search for any experiential contributions to innate behaviors if those behaviors by definition develop independently of experience? In the words of Developmentalists Thelen and Adolph ( 1992 ), nativism “leads to a static science, with no principles for understanding change or for confronting the ultimate challenge of development, the source of new forms in structure and function” (p. 378).

A commitment to maturational theory is likely one of the reasons why studies of motor development remained relatively dormant for decades following its heyday in the 1930–1940s (Thelen, 2000 ). Likewise, a commitment to maturational theory also helps explain the delay in neuroscience to examine how the brain physically changes in response to environmental conditions, a line of inquiry that only began in the 1960s.

In addition to the theoretical pitfalls of nativism, Developmentalists point to numerous studies that show how some seemingly native behaviors and innate constraints on learning are driven by the experiences of animals. For example, the comparative psychologist Gilbert Gottlieb ( 1971 ) showed that newly hatched ducklings display a naïve preference for a duck maternal call over a (similarly novel) chicken maternal call (Gottlieb, 1971 ), even when duck embryos were repeatedly exposed to the chicken call prior to hatching (Gottlieb, 1991 ). It would be easy to conclude that ducklings have an innate preference to approach their own species call and that they are biologically constrained (contraprepared) in learning a chicken call. However, Gottlieb found that the naïve preference for the duck call stemmed from exposure to the duck embryos’ own (or other) vocalizations in the days before hatching (Gottlieb, 1971 ). Exposure to these vocalizations not only made duck maternal calls more attractive, but it hindered the establishment of a preference for heterospecific calls. When duck embryos were reared in the absence of the embryonic vocalizations (by devocalizing embryos in ovo ) and exposed instead to chicken maternal calls, the newly hatched ducklings preferred chicken over duck calls (Gottlieb, 1991 ). These studies clearly showed how seemingly innate, biologically based preferences and constraints on learning derived from prenatal sensory experiences.

For Developmentalists, findings like these suggest that nativist explanations of any given behavior are statements of ignorance about how that behavior actually develops. As Kuo and Lehrman made clear, nativist terms are labels, not explanations. Although such appeals are couched in respectable, scientific language (e.g., “X is due to maturation, genes, or heredity”), they argue it would be more accurate simply to say that “We don’t know what causes X” or that “X is not due to A, B, or C.” Indeed, for Developmentalists, the more we unpack the complex dynamics about how traits develop, the less likely we are to use labels like nature or nurture (Blumberg, 2005 ).

On the other hand, Developmentalists recognize that labeling a behavior as “learned” also falls short as an explanatory construct. The empiricist position that knowledge or behavior is learned does not adequately take into account that what is learned and how easily something is learned depends on (a) the physiological and developmental status of the person, (b) the nature of the surrounding physical and social context in which learning takes place, and the (c) experiential history of the person. The empiricist tendency to say “X is learned or acquired through experience” can also short-circuit developmental analyses in the same way as nativist claims.

Still, Developmentalists appreciate that classifying behaviors can be useful. For example, the development of some behaviors may be more robust, reliably emerging across a range of environments and/or remaining relatively resistant to change, whereas others are more context-specific and malleable. Some preferences for stimuli require direct experience with those stimuli. Other preferences require less obvious (indirect) types of experiences. Likewise, it can still be useful to describe some behaviors in the ways shown in Table 1 . Developmentalists simply urge psychologists to resist the temptation to treat these behavioral classifications as implying different kinds of explanations (Johnston, 1987 ).

Rather than treat nature and nurture as separate developmental sources of causation (see Figure 1 ), Developmentalists argue that a more productive way of thinking about nature–nurture is to reframe the division as that between product and process (Lickliter & Honeycutt, 2015 ). The phenotype or structure (one’s genetic, epigenetic, anatomical, physiological, behavioral, and mental profile) of an individual at any given time can be considered one’s “nature.” “Nurture” then refers to the set of processes that generate, maintain, and transform one’s nature (Figure 2 ). These processes involve the dynamic interplay between phenotypes and environments.

Figure 2. The developmentalist alternative view of nature–nurture as product–process. Developmentalists view nature and nurture not as separate sources of causation in development (see Figure 1 ) but as a distinction between process (nurture) and product (nature).

It is hard to imagine any set of findings that will end debates about the roles of nature and nurture in human development. Why? First, more so than other assumptions about human development, the nature–nurture dichotomy is deeply entrenched in popular culture and the life sciences. Second, throughout history, the differing positions on nature and nurture were often driven by other ideological, philosophical, and sociopolitical commitments. Thus the essential source of tension in debates about nature–nurture is not as much about research agendas or evidence as about basic differences in metatheoretical positions (epistemological and ontological assumptions) about human behavior and development (Overton, 2006 ).

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Urgent need for action now for increasing threat from invasive alien species

While invasive alien species have long been recognised as a major threat to nature and people, urgent action now is needed to tackle this global issue. This is the critical evaluation by the 88 authors, representing 101 organisations from 47 countries, of 'Curbing the major and growing threats from invasive alien species is urgent and achievable' published in Nature, Ecology & Evolution, including lead author Professor Helen Roy from the UK Centre for Ecology & Hydrology and the University of Exeter.

Focused on the main findings of the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES) thematic assessment report on invasive alien species and their control*, the paper also highlights that the impacts of invasive alien species observed today are likely to underestimate the magnitude of future impacts. Also, the interactions among biodiversity drivers are key as no driver acts in isolation.

Co-chair of the IPBES IAS assessment and lead author, Professor Helen Roy from the UKCEH and the University of Exeter, said: "The paper brought together the entire expert team of the IAS assessment, with this diverse group spanning many disciplines with perspectives from around the world drawing the same conclusion about the need for urgent action on the major and growing threat of invasive alien species.

"With the number of invasive alien species set to rise, the IPBES invasive alien species assessment provides the evidence-base and options to inform immediate and ongoing action. To achieve this there is a need for collaboration, communication and cooperation, not only across borders but within countries."

Professor Peter Stoett from Ontario Tech University, co-chair of the IPBES IAS assessment, added: "Interdisciplinarity is key to the success of IPBES assessments. It was wonderful to see social science and humanities experts interacting with invasion biologists and other natural scientists, in a community-building process that will inform policy decisions moving forward."

The threats posed by invasive alien species are expected to continue to rise. Every year, approximately two hundred new alien species are now being introduced globally by human activities to regions they had not been recorded before. Even without the introduction of new species by human activities, already established alien species will continue to naturally expand their geographic ranges and spread into new countries and regions, with many causing negative impacts. Simple extrapolations from the impacts of invasive alien species observed today are likely to underestimate the magnitude of future impacts.

Interactions among drivers of biodiversity loss are amplifying biological invasions with no driver acting in isolation. Climate change is a major driver facilitating the establishment and spread of invasive alien species into previously inhospitable regions. For example, climate warming is enabling aquatic and terrestrial invasive alien species to establish and spread poleward, including into the Arctic and Antarctic regions. Also, in some mountainous regions, climate change, acting together with other drivers of biodiversity loss, has allowed invasive alien species to extend their ranges into higher elevations twice as fast as native species.

The IPBES invasive species assessment provided the first comprehensive synthesis of evidence globally concluding that the threat of biological invasions is major but can be mitigated with urgent cross-sectorial cooperative and collaborative action. Co-developing management actions with multiple stakeholders including government and private sector stakeholders, and Indigenous Peoples and local communities will be critical to achieving success in addressing biological invasions.

Aníbal Pauchard, co-chair of the IPBES IAS assessment and Professor at the University of Concepción, Chile, highlights the importance of inclusion within the assessment: "This is not only the most comprehensive global assessment on invasive alien species to date, but also the selection of experts and the evidence gathering was done under the highest standards of inclusivity, resulting in a report which provides critical insights for all stakeholders."

Coordinating bodies such as the Non-Native Species Secretariat can ensure effective collaboration among diverse stakeholder groups. Indeed, management actions in response to incursions of the Asian hornet ( Vespa velutina ) in the UK have involved multiple stakeholders coming together to ensure rapid flow of information following detection of the species leading to effective control of nests.

The paper recognises that the engagement of the general public through awareness raising campaigns, education and community science platforms also contributes to establishing shared responsibilities in managing biological invasions. Community science initiatives, supported by digital identification tools are important for the rapid detection of invasive alien species. Records submitted by the public through the Asian Hornet Watch app in the UK are making a major contribution to Vespa velutina (Asian hornet) early warning and rapid response.

• Invasive Species
• New Species
• Exotic Species
• Environmental Awareness
• Environmental Policies
• Land Management
• Ocean Policy
• Invasive species
• Biodiversity Action Plan
• United Nations Development Programme
• Water hyacinth
• Purple loosestrife
• Sustainable land management
• Unified neutral theory of biodiversity

Story Source:

Materials provided by UK Centre for Ecology & Hydrology . Note: Content may be edited for style and length.

Journal Reference :

• Helen E. Roy, Aníbal Pauchard, Peter J. Stoett, Tanara Renard Truong, Laura A. Meyerson, Sven Bacher, Bella S. Galil, Philip E. Hulme, Tohru Ikeda, Sankaran Kavileveettil, Melodie A. McGeoch, Martin A. Nuñez, Alejandro Ordonez, Sebataolo J. Rahlao, Evangelina Schwindt, Hanno Seebens, Andy W. Sheppard, Vigdis Vandvik, Alla Aleksanyan, Michael Ansong, Tom August, Ryan Blanchard, Ernesto Brugnoli, John K. Bukombe, Bridget Bwalya, Chaeho Byun, Morelia Camacho-Cervantes, Phillip Cassey, María L. Castillo, Franck Courchamp, Katharina Dehnen-Schmutz, Rafael Dudeque Zenni, Chika Egawa, Franz Essl, Georgi Fayvush, Romina D. Fernandez, Miguel Fernandez, Llewellyn C. Foxcroft, Piero Genovesi, Quentin J. Groom, Ana Isabel González, Aveliina Helm, Ileana Herrera, Ankila J. Hiremath, Patricia L. Howard, Cang Hui, Makihiko Ikegami, Emre Keskin, Asuka Koyama, Stanislav Ksenofontov, Bernd Lenzner, Tatsiana Lipinskaya, Julie L. Lockwood, Dongang C. Mangwa, Angeliki F. Martinou, Shana M. McDermott, Carolina L. Morales, Jana Müllerová, Ninad Avinash Mungi, Linus K. Munishi, Henn Ojaveer, Shyama N. Pagad, Nirmalie P. K. T. S. Pallewatta, Lora R. Peacock, Esra Per, Jan Pergl, Cristina Preda, Petr Pyšek, Rajesh K. Rai, Anthony Ricciardi, David M. Richardson, Sophie Riley, Betty J. Rono, Ellen Ryan-Colton, Hanieh Saeedi, Bharat B. Shrestha, Daniel Simberloff, Alifereti Tawake, Elena Tricarico, Sonia Vanderhoeven, Joana Vicente, Montserrat Vilà, Wycliffe Wanzala, Victoria Werenkraut, Olaf L. F. Weyl, John R. U. Wilson, Rafael O. Xavier, Sílvia R. Ziller. Curbing the major and growing threats from invasive alien species is urgent and achievable . Nature Ecology & Evolution , 2024; DOI: 10.1038/s41559-024-02412-w

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REVIEW article

The human–nature relationship and its impact on health: a critical review.

• Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK

Within the past four decades, research has been increasingly drawn toward understanding whether there is a link between the changing human–nature relationship and its impact on people’s health. However, to examine whether there is a link requires research of its breadth and underlying mechanisms from an interdisciplinary approach. This article begins by reviewing the debates concerning the human–nature relationship, which are then critiqued and redefined from an interdisciplinary perspective. The concept and chronological history of “health” is then explored, based on the World Health Organization’s definition. Combining these concepts, the human–nature relationship and its impact on human’s health are then explored through a developing conceptual model. It is argued that using an interdisciplinary perspective can facilitate a deeper understanding of the complexities involved for attaining optimal health at the human–environmental interface.

Introduction

During the last century, research has been increasingly drawn toward understanding the human–nature relationship ( 1 , 2 ) and has revealed the many ways humans are linked with the natural environment ( 3 ). Some examples of these include humans’ preference for scenes dominated by natural elements ( 4 ), the sustainability of natural resources ( 5 , 6 ), and the health benefits associated with engaging with nature ( 7 – 9 ).

Of these examples, the impacts of the human–nature relationship on people’s health have grown with interest as evidence for a connection accumulates in research literature ( 10 ). Such connection has underpinned a host of theoretical and empirical research in fields, which until now have largely remained as separate entities.

Since the late nineteenth century a number of descriptive models have attempted to encapsulate the dimensions of human and ecosystem health as well as their interrelationships. These include the Environment of Health ( 11 ), the Mandala of Health ( 12 ), the Wheel of Fundamental Human Needs ( 13 ), the Healthy Communities ( 14 ), the One Health ( 15 ), and the bioecological systems theory ( 16 ). Each, however, have not fully incorporated all relevant dimensions, balancing between the biological, social, and spatial perspectives ( 17 , 18 ). In part this is due to the challenges of the already complex research base in relation to its concept, evidence base, measurement, and strategic framework. Further attention to the complexities of these aspects, interlinkages, processes, and relations is required for a deeper sense of understanding and causal directions to be identified ( 19 ).

This article reviews the interconnectivities between the human–nature relationship and human health. It begins by reviewing the each of their concepts and methodological approaches. These concepts will be converged to identify areas of overlap as well as existing research on the potential health impacts in relation to humanity’s degree of relationship to nature and lifestyle choices. From this, a developing conceptual model is proposed, to be inclusive of the human-centered perspective of health, viewing animals and the wider environment within the context of their relationship to humans. The model combines theoretical concepts and methodological approaches from those research fields examined in this review, to facilitate a deeper understanding of the intricacies involved for improving human health.

Defining the Human–Nature Relationship

It is beyond the scope of this paper to review the various connections at the intersect of humanity and the natural environment. Instead, I summarize key concepts and approaches from those four research fields (Evolutionary Biology, Social Economics, Evolutionary Psychology, and Environmentalism) outlined below, which have paid most attention to studying this research area. I then summarize areas of convergence between these connections in an attempt to describe the human–nature relationship, which will serve as background to this review.

It is anticipated that through drawing on these different fields of knowledge, a deeper level of understanding can be brought to the growing issue of humanity’s relationship with nature and its impact on health. This is because examining the human–nature relationship from a single disciplinary perspective could lead to partial findings that neglect other important sources as well as the complexities that exist between interlinkages, causal directions, processes, and relations.

Evolutionary Biology

Evolutionary biology is a branch of research that shortly followed Darwin’s ( 20 ) Theory of Evolution. It concerns the adaptive nature of variation in all animal and plant life, shaped by genetic architecture and developmental processes over time and space ( 21 ). Since its emergence over a century ago, the field has made some significant advances in scientific knowledge, but with intense debate still remaining among its central questions, including the rate of evolutionary change, the nature of its transitional processes (e.g., natural selection) ( 22 ). This in part owes to the research field’s interdisciplinary structure, formulated on the foundations of genetics, molecular biology, phylogeny, systematics, physiology, ecology, and population dynamics, integrating a diverging range of disciplines thus producing a host of challenging endeavors ( 23 , 24 ). Spanning each of these, human evolution centers on humanity’s life history since the lineage split from our ancestral primates and our adaptive synergy with nature.

In the last four decades, evolutionary biology has focused much attention on the cultural–genetic interaction and how these two inherent systems interrelate in relation to lifestyle and dietary choices [ Culturgen Evolution ( 25 ); Semi-Independent ( 26 ); Dual-Inheritance model ( 27 )]. Some of the well-known examples include humans’ physiological adaptation to agricultural sustenance ( 28 ), the gradual increase in lactose tolerance ( 29 ) as well as the susceptibility of allergic diseases (e.g., asthma and hay fever) in relation to decreasing microbial exposure ( 30 ).

This coevolutionary perspective between human adaptation and nature has been further conceptualized by Gual and Norgaard ( 31 ) as embedding three integrated systems (biophysical, biotic, and cultural). In this, culture is both constrained and promoted by the human genetics via a dynamic two-way interaction. However, bridging the gap between these research fields continues to generate much controversy, particularly as the nature of these evolutionary development processes differs widely (e.g., internal and external factors). This ongoing discussion is fueled by various scholars from multiple disciplines. Some have argued that one cannot assume all evolutionary mechanisms can be carried over into other areas ( 32 , 33 ), where genomes cannot evolve as quickly to meet modern lifestyle and dietary requirements ( 34 ). Conversely, others believe that humans have not entirely escaped the mechanisms of biological evolution in response to our cultural and technological progressions ( 35 ).

Evolutionary Psychology

Evolutionary psychology is a recently developed field of study, which has grown exponentially with interest since the 1980s. It centers on the adaptation of psychological characteristics said to have evolved over time in response to social and ecological circumstances within humanity’s ancestral environments ( 36 – 38 ). This reverse engineering approach to understanding the design of the human mind was first kindled by evolutionary theorist Charles Darwin ( 20 ) in the last few pages of Origin of Species ;

In the distant future … Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation [p. 447].

As such, evolutionary psychology is viewed by some to offer a metatheory that dissolves the traditional boundaries held in psychology (e.g., cognitive, social, personality, and development). Within this metatheory, all psychological theories implicitly believed by some to unify under this umbrella ( 37 ). However, the application of evolution to the study of psychology has not been without controversial debate in areas relating to cognitive adaptation, testability of hypotheses, and the uniformity of human nature ( 39 ).

During the past few decades, the field has presented numerous concepts and measures to describe human connectedness to nature. These include Deep Ecology ( 40 ), Extinction of Experience ( 41 ), Inclusion of Nature in Self ( 42 ), and Connectedness to Nature ( 43 ). However, the Biophilia hypothesis ( 44 ) remains the most substantially contributed to theory and argues for the instinctive esthetic preference for natural environments and subconscious affiliation for other living organisms. Supportive findings include humans’ preference for scenes dominated by natural elements ( 4 ), improved cognitive functioning through connectivity with nature ( 45 ) as well as instinctive responses to specific natural stimuli or cues (e.g., a common phobia of snakes) ( 46 ). More recently, evidence is emerging to suggest that connectivity to nature can generate positive impacts on one’s health, increasing with intensity and duration ( 47 ).

The underpinning of the Biophilia hypothesis centers on humanity’s source of attachment to nature beyond those on the surface particulars. Instead, it reflects thousands of years of evolutionary experience closely bonding with other living organisms ( 44 ). Such process is mediated by the rules of prepared and counter-prepared learning that shape our cognitive and emotional apparatus; evolving by natural selection via a cultural context ( 48 ). This innate value for nature is suggested to be reflected in the choices we make, experiences expressed as well as our longstanding actions to maintain our connection to nature ( 49 ). Nevertheless, many have gone on to recognize the research field’s need for revision and further evidentiary support through empirical analysis ( 50 ). Similarly, as other researchers have argued, these innate values should be viewed in complementary to other drivers and affinities from different sources that can also be acquired (e.g., technology and urban landscapes). This is because at the commonest level, as Orr ( 51 ) explains, humanity can learn to love what becomes familiar, a notion also reflected in the Topophilia (“love of place”) hypothesis ( 52 ).

Social Economics

Social economics is a metadiscipline in which economics is embedded in social, political, and cultural behaviors. It examines institutions, choice behavior, rationality as well as values in relation to markets ( 53 ). Owing to its diverse structure, the human–nature relationship has been explored in various contexts. These include the reflections of society’s values and identities in natural landscapes ( 54 ), condition of placelessness ( 55 ), and humanity’s growing ecosynchronous tendencies ( 56 ) as well as how the relationship has evolved with historical context ( 57 – 59 ). While the dynamics of human and nature coupled systems has become a growing interdisciplinary field of research, past work within social economics has remained more theoretical than empirically based ( 59 ).

The connection between the start of industrialized societies and the dynamically evolving human–nature relationship has been discussed by many ( 60 ), revealing a host of economic–nature conflicts. One example includes those metaphorically outlined in the frequently cited article “ The Tragedy of the Commons .” In this, it argues that the four laws of ecology are counter intuitive with the four laws of capitalism ( 5 , 6 ). Based on this perspective, the human–nature relationship is simplified to one of exchange value, where adverse costs to the environment are rarely factored into the equation ( 6 ). However, this is not to say that humanity’s increasing specialization and complexity in most contemporary societies are distinct from nature but still depend on nature to exert ( 61 ).

Central to the tenets outlined in Tragedy of the Commons is the idea of “gradually diminishing freedom” where a population can increasingly exceed the limits of its resources if avoidance measures are not implemented (e.g., privatization or publicly owned property with rights of entry) ( 5 , 62 ). Yet, such avoidance measures can be seen to reflect emerging arguments in the field of environmental justice, which researches the inequalities at the intersection between environmental quality, accessibility, and social hierarchies ( 63 ). These arguments derive from the growing evidence that suggests the human–nature relationship is seemingly disproportionate to those vulnerable groups in society (e.g., lack of green spaces and poor air quality), something public health researchers believe to be a contributing factor to health inequities ( 64 ). As such, conflicts between both private and collective interests remain a challenge for future social economic development ( 65 ). This was explored more fully in Ostrom’s ( 66 ) research on managing a common pool of resources.

Environmentalism

Environmentalism can be broadly defined as an ideology or social movement. It focuses on fundamental environmental concerns as well as associated underlying social, political, and economic issues stemming from humanity’s interactions affecting the natural environment ( 67 , 68 ). In this context, the human–nature relationship has been explored through various human-related activities, from natural resource extraction and environmental hazards to habitat management and restoration. Within each of these reflects a common aspect of “power” visible in much of the literature that centers on environmental history ( 69 ). Some examples included agricultural engineering ( 70 ), the extinction of animals through over hunting ( 71 ) as well as the ecological collapse on Easter Island from human overexploitation of natural resources, since disproven ( 72 – 74 ). Yet, in the last decade, the field’s presupposed dichotomy between humans and nature in relation to power has been critically challenged by Radkau ( 75 ) who regards this perspective as misleading without careful examination. Instead, they propose the relationship to be more closely in synchrony.

Power can be characterized as “ A person, institution, physical event or idea … because it has an impact on society: It affects what people do, think and how they live ” ( 76 ). Though frequently debated in other disciplines, in the context of the human–nature relationship, the concept of “power” can be exerted by both nature and humanity. In regards to nature’s power against humanity, it has the ability to sustain society as well as emphasize its conditional awareness, environmental constraints, and fragilities ( 77 ). In contrast, humanity’s power against nature can take the form of institutions, artifacts, practices, procedures, and techniques ( 70 ). In the context of this review, it focuses on nature’s powers against humanity.

It has been argued that human power over nature has altered and weakened in dominance ( 75 ) since the emergence of Rachel Carson’s book Silent Spring in 1962, and later concepts of Gaia ( 78 ), Deep Ecology ( 40 ), and Sustainable Development ( 79 ). Instead, humanity’s power toward nature has become one of a moral sense of protectionism or the safeguarding of the environment ( 80 ). This conservative behavior (e.g., natural defenses, habitat management, and ecological restoration) can be termed “Urgent Biophilia” ( 81 ) and is the conscious urge to express affinity for nature pending an environmental disaster. As Radkau ( 69 ) suggests, with warnings of climatic change, biodiversity loss, and depletions in natural resources, this poses a threat to humanity. As such, this will eventually generate a turning point where human power is overwhelmed by the power of nature, bringing nature and power into a sustainable balance. Nonetheless, as many also highlight, humanity’s responses to environmental disasters can directly impinge on an array of multi-causalities of intervening variables (e.g., resource depletion and social economics) and the complexity of outcomes ( 82 ).

An Interdisciplinary Perspective of the Human–Nature Relationship

Through exploring the key concepts found in evolutionary biology, social economics, evolutionary psychology, and environmentalism, this has enabled a broader understanding of the various ways humans are connected to the natural environment. Each should not be viewed as separate entities, but rather that they share commonalities in terms of mutual or conjoint information and active research areas where similarities can occur (see Table 1 below). For example, there is a clear connection between social economics, evolutionary psychology, and biology in areas of health, lifestyle, and biophilic nature ( 40 , 53 , 81 ) as well as between social economics and the environment in regards to balancing relationships of power ( 5 , 75 ). Similarly, economic–nature conflicts can occur between disciplines evolutionary psychology and social economics in relation to people’s affiliation for nature and industrial growth.

Table 1. A summarized overview of human–nature relationship connections between those research fields explored .

Our understanding of the human–nature relationship and its underlying mechanisms could be further understood from an interdisciplinary perspective. In essence, the human–nature relationship can be understood through the Biophilia concept of humanity’s affiliation with nature as well as related concepts and measures to describe human connectedness to nature ( 49 – 53 ). Equally, Orr’s ( 51 ) perspective that at the commonest level humans can acquire other affinities to or learn to love different elements than those of the natural world (e.g., technology and urban environments) adds to this understanding. Further, while humanity, and indeed nature also, has not entirely escaped change, it cannot be assumed that all have been shaped by evolutionary mechanisms ( 42 , 44 ). Some have been shaped by what Radkau ( 75 ) terms as the power shift between humans and nature, which is evolving, as it has and will keep on doing. As such, the human–nature relationship goes beyond the extent to which an individual believes or feels they are part of nature. It can also be understood as, and inclusive of, our adaptive synergy with nature as well as our longstanding actions and experiences that connect us to nature. Over time, as research and scientific knowledge progresses, it is anticipated that this definition of the human–nature relationship will adapt, featuring the addition of other emerging research fields and avenues.

Defining Health

Conceptualizing “health” has often generated complex debates across different disciplines owing to its multidimensional and dynamic nature ( 83 ). It is, however, beyond the scope of this paper to review the many ways these concepts have been previously explored ( 84 – 86 ). Instead, “health” is reviewed and viewed more generally through the lens of the World Health Organization 1948 definition.

The World Health Organization defined “health” simply as the physical, social, and mental well-being of humanity, in which “health” was widened beyond those biomedical aspects (e.g., disease and illness) to encompass the socioeconomic and psychological domains ( 85 ). This classical definition advocated health’s shift toward a holistic perspective, with emphasis on more positive attributes ( 84 , 87 ) and was not simply “ the mere absence of disease and infirmity ” [( 83 ), p. 1]. It also reflected people’s ambitious outlook after the Second World War, when health and peace were seen as inseparable ( 83 , 84 ). Since then, this shift has seen a major growth in the last 30 years, primarily in areas of positive health and psychology ( 88 – 92 ).

Despite its broad perspective of human health, the definition has also encountered criticism in relation to its description and its overall reflectance of modern society. For instance, the use of the term “completeness” when describing optimal health has been regarded by many as impractical. Instead, Huber et al ( 83 ) propose health to be the “ability to adapt and to self-manage” and invite the continuation of further discussions and proposals of this definition to be characterized as well as measured through its three interrelated dimensions; physical, mental, and social health. Similarly, others have highlighted the need to distinguish health from happiness ( 84 ) or its inability to fully reflect modern transformations in knowledge and development (e.g., technology, medicine, genomics as well as physical and social environments) ( 86 ). As such, there have been calls to reconceptualize this definition, to ensure further clarity and relevance for our adaptive societies ( 83 ).

Broadly, health has been measured through two theoretical approaches; subjective and objective ( 85 ). The subjective approach is based on individual’s perceived physical, emotional, and cognitive experiences or functioning. By contrast, the objective approach measures those variables, which are existing and measurable external to an individual’s internal experience such as living conditions or human needs that enable people to lead a good life (e.g., health markers, education, environment, occupational attainment, and civic involvement) ( 85 ). Together, these approaches provide a more comprehensive picture of a person’s health status, which are applicable across its three health components (physical, mental, and social), as described below.

First, physical health is defined as a healthy organism capable of maintaining physiological fitness through protective or adaptive responses during changing circumstances ( 83 ). While it centers on health-related behaviors and fitness (including lifestyle and dietary choices), physiological fitness is considered one of the most important health markers thought to be an integral measure of most bodily functions involved in the performance of daily physical exercise ( 93 ). These can be measured through various means, with examples including questionnaires, behavioral observations, motion sensors, and physiological markers (e.g., heart rate) ( 94 ).

Second, mental health is often regarded as a broad concept to define, encapsulating both mental illness and well-being. It can be characterized as the positive state of well-being and the capacity of a person to cope with life stresses as well as contribute to community engagement activities ( 83 , 95 ). It has the ability to both determine as well as be determined by a host of multifaceted health and social factors being inextricably linked to overall health, inclusive of diet, exercise, and environmental conditions. As a result, there are no single definitive indicators used to capture its overall measurement. This owes in part to the breadth of methods and tends to represent hedonic (e.g., life satisfaction and happiness) and eudaimonic (e.g., virtuous activity) aspects of well-being, each known to be useful predictors of physical health components ( 96 ).

Third, social health can be generalized as the ability to lead life with some degree of independence and participate in social activities ( 83 ). Indicators of the concept revolve around social relationships, social cohesion, and participation in community activities. Further, such mechanisms are closely linked to improving physical and mental well-being as well as forming constructs, which underline social capital. Owing to its complexity, its measurement focuses on strengths of primary networks or relationships (e.g., family, friends, neighborliness, and volunteering in the community) at local, neighborhood, and national levels ( 97 ).

Current Knowledge on the Human–Nature Relationship and Health

This section summarizes existing theoretical and literature research at the intersection of the human–nature relationship and health, as defined in this review. This has been explored through three Subsections “Physical Health,” “Mental Health,” and “Social Health.” It aims to identify areas of convergence as well as gaps and limitations.

Physical Health

Though it is widely established that healthy eating and regular exercise have major impacts on physical health ( 98 ), within the past 30 years research has also identified that exposure to nature (e.g., visual, multisensory, or by active engagement) is equally effective for regulating our diurnal body rhythms to ensure physical vitality ( 99 ). Such notion stems from Wilson’s ( 44 ) proposed “Three Pillars of Biophilia” experience categories (Nature of Space, Natural Analogs, and Nature in Space), which relate to natural materials and patterns experienced in nature, inducing a positive impact on health ( 9 ). Empirical research in this domain was first carried out by Ulrich ( 46 ) who found that those hospital patients exposed to natural scenery from a window view experienced decreased levels of pain and shorter recovery time after surgery. Following this, research in this academic field has grown exponentially and encompasses a large literature base on nature’s health benefits. These include improvements in neurological and circadian rhythms relating to exposures to natural sunlight ( 100 , 101 ), undergoing “Earthing” or physical contact with the Earth’s surface regulates diurnal body rhythms ( 102 ) as well as walking activities in forest environments reducing blood pressure levels ( 8 ).

In spite of its increasing findings, some have suggested the need for further objective research at the intersect of nature-based parameters and human health ( 9 ). One reason for this is that most studies have yet to be scrutinized to empirical scientific analysis ( 55 , 103 ) owing to the research area’s reliance on self-reported measures with the need for inclusion of more quantitative forms of data (e.g., physiological and biochemical indicators). This presents inherent difficulty in comparing assessment measures or different data types relative to the size and scale of the variables being evaluated ( 9 ). Further, there still remain evidence gaps in data on what activities might increase levels of physical health as well as limited amount of longitudinal datasets from which the frequency, duration, and causal directions could be inferred ( 104 ).

Mental Health

Mental health studies in the context of connecting with nature have also generated a growing research base since the emergence of the Biophilia concept in the mid-1980s ( 45 ). Much of its research within the Evolutionary Psychology discipline examines the recuperative effects of nature on well-being and its beneficial properties following researcher’s arguments of humanity’s affiliation for nature ( 105 ). Supporting research has been well documented in literature during the last few decades. These include “Heraclitean motion” or natural movement ( 14 ), natural sounds ( 106 ), children’s engagement activities within green settings ( 7 , 107 ) as well as esthetic preferences for nature and natural forms ( 4 , 49 ).

Criticisms of this research area center on the inability to decipher causal effects and direction of such benefits and in part relates to its predominant focus on “recuperative measure” than that of detecting its “source” ( 105 ). In light of this, reviewers repeatedly remark on researchers’ tendencies to focus on outcomes of well-being, neglecting the intervening mechanisms that sustain or inhibit well-being ( 108 ). Similarly, further mixed-method approaches and larger sample sizes are needed in this research field. This would enhance existing evidence gaps to enhance existing knowledge of variable interlinkages with other important sources (e.g., physical and social health aspects) as well as the diversity that exists between individuals ( 104 ).

Social Health

In the last two decades, the relationship between people and place in the context of green spaces has received much attention in academic literature in regards to its importance for the vitality of communities and their surrounding environments ( 109 ). As studies have shown, the presence of green space can promote social cohesion and group-based activities, aspects that are crucial for maintaining social ties, developing communities, and increasing individual’s well-being (e.g., horticulture and ecological restoration) ( 110 ). Examples of findings include usage of outdoor space exponentially increases with number and locality of trees ( 111 ), children’s activities in green spaces improves social development ( 7 ) as well as accessibility to green spaces enhances social bonds in communities ( 112 ).

One of the main limitations within this field relates to the generally perceived idea that public green spaces are freely open to everyone in all capacities ( 113 ). This limitation has been, as already, highlighted from the emerging arguments in the field of environmental justice and economic–nature conflicts ( 63 ). As such, many researchers highlight the need to maintain awareness of other barriers that might hinder cohesion and community participation (e.g., semi-public space and social exclusion). Further, there still remains a gap between academic research and local knowledge, which would otherwise lead to more effective interventions. However, without implementing participatory engagement, many studies risk misrepresenting the true social, economic, and political diversity that would increase both our understanding of “real life” problems of concern as well as bringing depth to data collected ( 114 ). Nonetheless, for such approach to be implemented requires sufficient time, cost, and an adequate scale of resources to ensure for aspects of coordination, communication, and data validation ( 115 ).

Impacts of the Human–Nature Relationship on Health

During the past four decades, researchers, health practitioners, and environmentalists alike have begun to explore the potential link between the human–nature relationship and its impact people’s health ( 10 ). This in part owes to the increasing evidence accumulating in research literature centering on the relationships between the following areas: chronic diseases and urbanization, nature connectedness and happiness, health implications of contemporary society’s lifestyle choices as well as the adverse impacts of environmental quality on the health of humans and non-humans alike ( 116 , 117 ).

Such health-related effects that have been alluded to include chronic diseases, social isolation, emotional well-being as well as other psychiatric disorders (e.g., attention deficit disorders and anxiety) and associated physical symptoms ( 7 , 118 ). Reasons for these proposed links have been suggested to stem from various behavioral patterns (e.g., unhealthy diets and indoor lifestyles) associated with consumerism, urbanization, and anthropogenic polluting activities ( 117 , 119 ). Further, these suggested links have been inferred, by some, to be visible in other species (e.g., insects, mice, and amphibians) as a consequence to living in unnatural habitats or enclosures ( 120 – 122 ). Nonetheless, research within this field remains speculative with few counter examples (e.g., some species of wildlife adapting to urban environments), requiring further empirical analysis ( 108 ).

With a growing trend in the number of chronic diseases and psychiatric disorders, costs to the U. K.’s National Health Service (NHS) could rise as the use of prescriptive drugs and medical interventions increases ( 123 ). However, this anticipated trend is considered to be both undesirable and expensive to the already overwhelmed health-care system ( 124 ). In concurrence are the associated impacts on health equity ( 125 , 126 ), equating to further productivity and tax losses every year in addition to a growing gap in health inequalities ( 127 ).

Furthermore, population growth in urbanized areas is expected to impact future accessibility to and overall loss of natural spaces. Not only would this have a direct detrimental effect on the health of both humans and non-humans but equally the functioning and integrity of ecosystem services that sustain our economic productivity ( 128 ). Thereby, costs of sustaining our human-engineered components of social–ecological systems could rise, having an indirect impact on our economic growth and associated pathways connecting to health ( 129 , 130 ). As such, researchers have highlighted the importance of implementing all characteristics when accounting ecosystem services, particularly the inclusion of natural and health-related capital, as well as their intervening mechanisms. This is an area, which at present remains difficult to synthesize owing to fragmented studies from a host of disciplines that are more conceptually rather than empirically based ( 131 ).

Toward an Interdisciplinary Perspective of Human and Ecosystem Health

Since the late nineteenth century, a number of descriptive models have been developed to encapsulate the dimensions of human health and the natural environment as well as their interrelationships ( 17 ). These include the Environment of Health ( 11 ), the Mandala of Health ( 12 ), the Wheel of Fundamental Human Needs ( 13 ), and the Healthy Communities ( 14 ). As VanLeeuwen et al ( 17 ) highlight in their review, each have not fully incorporated all relevant characteristics of ecosystems (e.g., multiple species, trade-offs, and feedback loops, as well as the complex interrelationships between socioeconomic and biophysical environments). Further, the Bioecological systems theory model encapsulates the biopsychological characteristics of an evolving theoretical system for scientific study of human development over time ( 16 , 132 ). However, the model has been suggested by some ( 133 , 134 ) to be static and compartmentalized in nature, emphasizing instead the importance of evolving synergies between biology, culture, and technology.

More recently, the concept “One Health” has gradually evolved and increased with momentum across various disciplines ( 15 ). It is broadly defined as the attainment of optimal health across the human–animal–environmental interfaces at local, national, and global levels. It calls for a holistic and universal approach to researching health, an ideology said to be traceable to pathologist Rudolf Virchow in 1858 ( 18 ). Yet, the concept has received criticisms regarding its prominence toward the more biological phenomena (e.g., infectious diseases) than those of a social science and spatial perspective ( 18 , 135 ). Some have therefore suggested its need to adopt an interdisciplinary approach to facilitate a deeper understanding of the complexities involved ( 13 ).

To address these limitations identified in the above models, a suggested conceptual model has been outlined below (Figure 1 ). It is both inclusive of all relevant characteristics of ecosystems, their continuously evolving synergies with human health as well as a balance between the biological, social, and spatial perspectives. This is achieved through combining the perspective of the human–nature relationship, as summarized in Section “Defining the Human–Nature Relationship” of this review, with those human-centered components of health (physical, mental, and social), as defined by the World Health Organization in 1948 in Section “Defining Health.” It aims to facilitate a deeper understanding of the complexities involved for attaining optimal human health ( 19 ). I will now describe the conceptual model.

Figure 1. Interdisciplinary perspective of human and ecosystem health [image on the inside circle is by Baird ( 136 ) with the background image, added text, and embedded illustrations being the author’s own work] .

First, the outer circle is representative of “nature” that both encompasses and interconnects with the three human-centered components of health (physical, mental, and social). Through this it emphasizes humanity’s interrelationship with the environment. As identified in Section “Defining the Human–Nature Relationship” of this review, the human–nature relationship can be experienced through various biological, ecological, and behavioral connections. For instance, social, political, and economic issues stemming from humanity’s interactions affecting the natural environment (e.g., natural resources, environmental hazards, habitat management, and restoration), as explored in Subsections “Social Economics” and “Environmentalism.”

Second, in the inner circle, the three components of human health (physical, mental, and social) are interconnected through a cohesive triangle to reflect their interdisciplinary and dynamic natures, as outlined in Section “Defining Health.” Further, this cohesive triangle acts on two levels. First, as a single construct of health based on these components combined. Second, the underlying intervening mechanisms that sustain or inhibit health, which can derive from each of these separately ( 105 ). Thereby, it not only focuses on the outcomes or “recuperative measure” of health but also the source of such outcomes and their directions, as highlighted in Section “Mental Health” ( 104 ).

The middle circle represents the interconnected relationship between humanity and the natural environment with relevance to human health (see Current Knowledge on the Human–Nature Relationship and Health). This has been indicated by the two-way arrows and incorporates Gual and Norgaard’s ( 31 ) coevolutionary perspective between human adaptation and the natural environment. In this way, the relationship is continually interconnected via two-way physical and perceptual interactions. These are embedded within three integrated systems (biophysical, biotic, and cultural), with all humanity knows of the world comes through such mediums ( 31 ). As such, the human–nature relationship goes beyond the extent to which an individual believes or feels they are affiliated with nature (e.g., Biophilia concept). It can also be understood as, and inclusive of, our adaptive synergy with nature as well as our longstanding actions and experiences that connect us to nature.

Utilizing this developing conceptual model, methodological approaches can be employed from those research fields explored in this review, enabling a more interdisciplinary framework. The characteristics, descriptions, implications, and practicalities of this are detailed in Table 2 below. The advantage of this is that a multitude of knowledge from both rigorous scientific analysis as well as collaborative participatory research can be combined bringing a greater depth to data collected ( 114 ). This could be achieved through using more mixed-method approaches and adopting a pragmatic outlook in research. In this way, the true social, economic, and political diversity of “real life” as well as the optimal human health at the human–environmental interface can be identified. As such, a more multidimensional perspective of human health would be gained, knowledge that could be implemented to address those issues identified in Section “Impacts of the Human–Nature Relationship on Health” (e.g., improving nature and health ecosystem service accounting). Nonetheless, adopting a pragmatic outlook brings its own challenges, as explored by Onwuegbuzie and Leech ( 137 ), with several researchers proposing frameworks that could be implemented to address these concerns ( 138 , 139 ).

Table 2. A summarized overview of human and ecosystem health from an interdisciplinary perspective .

Summary and Conclusion

One of the imperatives for this article is to review existing theoretical and research literature on the many ways that humans are linked with the natural environment within various disciplines. Although widely discussed across the main four research fields – evolutionary psychology, environmentalism, evolutionary biology, and social economics – there has been comparatively little discussion of convergence between them on defining the human–nature relationship. This paper therefore attempts to redefine the human–nature relationship to bring further understanding of humanity’s relationship with the natural environment from an interdisciplinary perspective. The paper also highlights important complex debates both within and across these disciplines.

The central discussion was to explore the interrelationships between the human–nature relationship and its impact on human health. In questioning the causal relationship, this paper addresses existing research on potential adverse and beneficial impacts in relation to humanity’s degree of relationship to nature and lifestyle choices. The paper also acknowledged current gaps and limitations of this link relative to the different types of health (physical, mental, and social), as characterized by the World Health Organization in 1948. Most of these relate to research at the intersect of nature-based parameters and human health being in its relative infancy. It has also been highlighted that the reorientation of health toward a well-being perspective brings its own challenges to the already complex research base in relation to its concept, measurement, and strategic framework. For a deeper sense of understanding and causal directions to be identified requires further attention to the complexities of these aspects’ interlinkages, processes, and relations.

Finally, a developing conceptual model of human and ecosystem health that is inclusive of the human-centered perspective is proposed. It is based on an interdisciplinary outlook at the intersection of the human–nature relationship and human health, addressing the limitations identified in existing models. To achieve this, it combines theoretical concepts and methodological approaches from those research fields examined in this review, bringing a greater depth to data collected. In attempting this, a balance between both rigorous scientific analysis as well as collaborative participatory research will be required, adopting a pragmatic outlook. In this way, an interdisciplinary approach can facilitate a deeper understanding of the complexities involved for attaining optimal health at the human–environmental interface.

Author Contributions

The author confirms being the sole contributor of this work and approved it for publication.

Conflict of Interest Statement

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Acknowledgments

The author would like to thank the following people for their advice and feedback during the writing of this manuscript: Muki Haklay, Pippa Bark-Williams, Mike Wood, Peter J. Burt, Catherine Holloway, Jenny Mindell, Claire Ellul, Elizabeth H. Boakes, Gianfranco Gliozzo, Chris Spears, Louisa Hooper, and Roberta Antonica. University College London and The Conservation Volunteers sponsored this research.

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Keywords: human health, human–nature relationship, natural environment, interdisciplinary

Citation: Seymour V (2016) The Human–Nature Relationship and Its Impact on Health: A Critical Review. Front. Public Health 4:260. doi: 10.3389/fpubh.2016.00260

Received: 21 July 2016; Accepted: 03 November 2016; Published: 18 November 2016

Reviewed by:

Copyright: © 2016 Seymour. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Valentine Seymour, valentine.seymour.12@ucl.ac.uk

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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Nature-Based Therapy in Individuals with Mental Health Disorders, with a Focus on Mental Well-Being and Connectedness to Nature—A Pilot Study

Lilly joschko.

1 Department of People and Society, The Swedish University of Agricultural Sciences, 234 22 Lomma, Sweden

Anna María Pálsdóttir

Patrik grahn, maximilian hinse.

2 Institute of Social Medicine, Epidemiology and Health Economics, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany

Associated Data

Quantitative data are available by contacting the corresponding author.

In times of social and ecological crises, such as COVID-19 with lockdowns and implementing the impact of climate change, mental health degrades. Being outdoors in nature can be health-promoting, can decrease depression, and increase mental well-being. This pilot study investigated the relationships between nature-based therapy, mental health, and individuals’ connectedness to nature. We hypothesize that nature-based therapy has a positive impact on individual mental health and connectedness to nature. A mixed-method approach was used to evaluate the effectiveness of nature-based therapy for young psychosomatic patients. The results demonstrated improvements in mental well-being and connectedness to nature through therapy. Additionally, depression scores decreased. Patients reported the importance of the therapist setting the space, the supportive environment, the poems that fostered the nature connection, improvement at the soul level, and overall doing something meaningful. Every patient experienced nature-based therapy as effective. To conclude, the study gives a first insight into the processes of nature-based therapy in the German population at work and the effectiveness of nature-based therapy. Further questions, e.g., season effects, longitudinal effects, and whether patients with low connectedness to nature gain more out of the intervention remain unanswered.

1. Introduction

In times of neo-liberalized global capitalism and global warming [ 1 , 2 ], we might face sociological and ecological crises, such as COVID-19, more often. During the COVID-19 pandemic, green and blue outdoor environments (gardens, parks, and water areas) were demonstrated to have beneficial effects on mental health [ 3 ]. Having no access to green and blue spaces increases symptoms of mental health disorders (e.g., depression and anxiety) during lockdown [ 3 ]. In particular, a strict lockdown severity significantly affected mental health, while contact with nature helped people to cope with these impacts [ 3 ]. Moreover, individuals with higher connectedness to nature in times of a pandemic tend to adapt easier and faster to behavioral changes and therefore, respond to the crisis better [ 4 ]. Hence, nature-based therapy could help to cope with mental stressors in future pandemics.

The World Health Organization (WHO) reports that approximately 280 million people are yearly affected by depression [ 5 ]. Depression is characterized by a “[…] depressed mood (feeling sad, irritable, empty) or a loss of pleasure or interest in activities […] poor concentration, feelings of excessive guilt or low self-worth, hopelessness about the future, thoughts about death or suicide, disrupted sleep, changes in appetite or weight, and feeling especially tired or low in energy” [ 5 ]. Additional bodily symptoms (e.g., pain, fatigue, weakness) may appear, which are not due to another medical condition [ 5 ]. There is a gender difference in the diagnosis. Women are approximately twice as likely to experience depression as men [ 6 , 7 ]. Furthermore, the WHO states that depression and anxiety have a significant economic impact. The yearly estimated cost to the global economy is USD 1 trillion in lost productivity because of unemployment [ 8 ].

The prevalence of depression in Germany is approximately 15.7% (2017), with increasing tendencies over the past years [ 6 ]. Costs related to depression in Germany are calculated at approximately €3000–5000 per diagnosed patient for total healthcare costs [ 9 ]. Older individuals appear to cope better with the demands of depression and are less influenced by it [ 10 , 11 ].

Depression and anxiety also affect psychosomatic patients. Indeed, psychosomatic medicine is based on the biopsychosocial model and explores the connections between social and physical external contextual factors and how they affect patients behaviorally, mentally, and biologically [ 5 , 12 , 13 ]. Psychosomatic medicine focuses on diagnoses where mental, behavioral, and somatic processes together affect medical outcomes, and involve different specialties, such as psychiatry, psychology, sociology, occupational medicine, neurology, internal medicine, and psychoneuroimmunology [ 14 ]. Germany has long worked from a biopsychosocial perspective and with psychosomatic approaches [ 15 , 16 ]. A model for psychosomatic medicine was developed that has conceptualized and integrated psychotherapeutic methods in clinical practice in a way to explicate psychosomatic medicine in everyday practice in health and the healthcare system. Several diseases are believed to stem from stress and strain in everyday life, which can be treated with a psychosomatic approach, where stress relief is an important factor in treatments [ 15 ]. Due to their complex disorders, it is difficult to diagnose patients who often have a long period of suffering; moreover, it is expensive for the healthcare system because of the ineffective treatment before the patients receive the treatment they really need. Consequently, the clinical disorder in psychosomatic patients is complex, requiring a holistic approach as a treatment.

Therapy guidelines for depression in Germany include pharmacotherapy, psychotherapy, and non-pharmacological somatic therapeutic interventions, such as electroconvulsive therapy, awake therapy, light therapy, physical training, repetitive transcranial magnetic stimulation, and vagus nerve stimulation [ 17 ]. Additionally, there are complementary treatment methods that are used as therapeutic interventions. One of these complementary treatment methods is nature-based therapy [ 18 , 19 ].

Nature-based therapy, which is based on the supportive environment theory, has an interdisciplinary approach that is biopsychosocial [ 20 , 21 , 22 ]. It is therefore well suited to treat psychosomatic diseases. Nature-based therapy is located and conducted outdoors [ 23 ], where the outdoor setting is of importance. The setup of the place has a tremendous influence on the participants and the therapy outcome [ 24 , 25 ]. The accessibility of the natural environment was highly important to promote a feeling of freedom and means for change in clients in elderly care [ 24 ]. For clients with stress-related mental health disorders (such as depression and burnout), it was most important to have refuge (a secluded place) and serene (peaceful, silent, safe, and secure) spaces for the recovery process [ 26 ].

Overall, natural environments can have a positive impact on health and well-being [ 27 , 28 , 29 ]. Being outdoors in nature can be, in general, health-promoting [ 28 ]. Furthermore, being outdoors can stimulate all the senses [ 23 , 30 , 31 ], increase the feeling of freedom and have a positive effect on the immune system [ 31 ]. Moreover, light and air can increase reflection and self-regulation for patients with depression [ 31 , 32 ]. A close connection with the seasons and their change might serve as a mirror to oneself and it is suggested to promote self-acceptance and self-love [ 31 , 32 ]. More specifically, nature-based therapy (including nature-based rehabilitation and horticultural therapy) has been demonstrated to positively affect individuals with mental health disorders [ 26 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. The research found that nature-based therapy improves patients’ self-esteem and decreases depression [ 40 ]; improves motivation and social interaction [ 41 ]; reduces healthcare consumption [ 39 ]; increases mental well-being, and engagement, and can give participants a sense of meaningfulness [ 21 , 35 ]. Overall, the potential of nature-based therapy is highly promising.

The overall recovery process in nature-based therapy might be influenced by the patients’ connectedness to nature. Connectedness to nature is defined as how strongly individuals feel they belong to nature and their individual emotional and cognitive beliefs about feeling related to nature [ 42 , 43 , 44 ]. Mayer and Frantz [ 42 ] suggest that connectedness to nature is an essential predictor of subjective mental well-being. Therefore, they invented the connectedness to nature scale (CNS) which is “[…] a measure designed to tap an individual’s affective, experiential connection to nature” [ 42 ] (p. 504). Choe, Jorgensen, and Sheffield [ 45 ] found that being in a natural environment, in particular, improves individuals’ connectedness to nature. Other studies investigated the correlation between connectedness to nature and mental well-being. Specifically, Cervinka, Röderer, and Hefler [ 45 ] found in their study ‘Are nature lovers happy?’ that psychological well-being is robustly correlated with connectedness to nature in healthy individuals. Indeed, further research found that connectedness to nature is positively associated with a subjective perception of happiness, well-being, physical and mental health, and life satisfaction [ 42 , 44 , 45 ].

The question arises: which underlying mechanisms drive the relationship between nature connectedness and mental well-being? Research in Japan demonstrated that place attachment had a positive and significant mediating effect on this association [ 46 ]. The relationship between nature connectedness and place attachment and between place attachment and individuals’ well-being was direct and significant. Consequently, their findings suggest that higher levels of well-being associated with nature connectedness are due to the sense of attachment to a place that nature provides [ 46 ]. Palsdottir et al. [ 21 ] found that the first part of nature-based therapeutic activities was about the patients finding a place in the garden (which they called their nature-place) where they could feel safe and de-stressed. For the therapy to work, this process was crucial. Grahn et al. suggest that this type of place attachment is similar to Bowlby and Ainsworth’s theory on human attachment [ 47 , 48 , 49 , 50 ]. The theory they put forward—the Calm and Connection Theory—is about archaic basic neurological systems being activated in natural areas that provide peace and security. Grahn et al. [ 50 ] propose that place attachment to natural environments (which can be described as nature connectedness) provides a possible role for the human oxytocinergic system to function as a physiological mediator for positive and health-promoting effects. Oxytocin promotes various types of social interaction and bonding and results in stress-reducing and healing effects (e.g., anti-inflammatory). Oxytocin is released, according to the theory, in connection with the attachment or bonding to certain natural places, developing in particularly safe and attractive places. Upon release, levels of fear and stress decrease, while levels of trust and well-being as well as health-promoting effects increase. Furthermore, the ability to develop coping skills or psychological development can also be promoted [ 50 ].

Our aim with this study was to investigate the relationships between nature-based therapy, mental health, and individuals’ connectedness to nature. Our hypotheses are as follows:

• Nature-based therapy has a positive impact on individuals’ mental health.
• Nature-based therapy fosters individuals’ connectedness to nature.
• There is a difference in the improvement of psychological well-being in patients with low vs. high connectedness to nature after nature-based therapy.

Does connectedness to nature improve mental well-being?

2. Materials and Methods

This study was conducted at the Gemeinschaftskrankenhaus Havelhöhe (GKH) hospital, Berlin, in the psychosomatic ward as an observational real-world data, prospective, cohort study without a control group. The study was part of a larger study evaluating the anthroposophical complex number in the DRG system (study “EVAL26”, registered under DRKS00020547) [ 51 ]. The study was reviewed and approved by the Ethics Committee of the Charité-Universitätsmedizin Berlin (EA2/089/19 dated 31 September 2019). All study participants gave their written informed consent to participate in the study. The study took place in compliance with professional regulations, the Declaration of Helsinki, and the recommendations of the ICH Guideline for Good Clinical Practice [ 52 , 53 ]. The authors confirm that all ongoing and related trials for this intervention are registered.

Patients of the ward, young adults (from 18 to 27 years), participated in nature-based therapy as a standard practice during their stay. Inclusion criteria were: minimum age of 18 years, ability and consent to participate in the study, and participation in nature-based therapy. Exclusion criteria were lack of understanding of the German language and severe acute or chronic illness, making participation or completion of the questionnaire impossible.

2.1. Design

During the period from May until July, the study took place at the GKH. The study was the subject of the Master’s thesis by the first author at the Swedish University of Agricultural Sciences (SLU). Furthermore, the study uses a mixed methodology approach [ 54 ].

The qualitative methods using a descriptive exploratory methodology were open questions in the questionnaire and participant observations [ 55 , 56 , 57 ]. In this case, the first author was present continuously and involved in the nature-based therapy in the garden at GKH and the transdisciplinary team meetings with the other therapists during the time of the study. This was accomplished to obtain an insider’s perspective by becoming part of the intervention and natural setting of the therapy. The role of the researcher was to explore and inspect to better understand how, and possibly, why, the connectedness to nature and mental well-being was influencing the mental health of the patients. The researcher also offered possibilities to engage in garden activities, shared garden knowledge, had individual talks with the patients, carried out observations, and took care of the data collection; consequently, the researcher had more insight into the different and complex processes at work during the intervention. The researcher is a trained and educated speech and language therapist and has previous experience in providing therapy. Thus, she knew how to approach patients and possessed background knowledge of therapeutic interventions and the patient-therapist relationship.

The quantitative part employs the positivist paradigm as its guiding methodological framework to evaluate and examine the outcome of the nature-based therapy program at the GKH hospital, Germany. Data were collected over a period of 3 months. Standardized questionnaires were answered before and after (as pre- and post-measurement) the participants’ 4-week stay at the hospital.

The quantitative evaluation of the treatment measured change of time at two measurement points: baseline (pre-) and post-testing design (see Figure 1 ). Since the stay at the hospital is not always six weeks, the decision was made to collect data only after the fourth week for each participant. This was to ensure comparability of the data among the participants. Thus, each person who received nature-based therapy filled in the questionnaire on two occasions: the first day of their nature-based therapy as pre-testing (before the intervention) and the second time, after the 4th week of the nature-based therapy as post-testing (after the intervention).

Visualization of the study design about how research was being conducted (including measurement tools, integrative therapy program, and time of the research).

The integrative therapy method at the GKH hospital, in which all patients participate, includes nature-based therapy (3 sessions, each comprising 60 min per week); psychotherapy with the integrative schema therapy approach [ 58 ] (1 session comprising 60 min per week), psychoeducation [ 59 ] (3 sessions, each comprising 50 min per week), music therapy (2 sessions, each comprising 50 min per week), painting/sculpting therapy (3 sessions, each comprising 60 min per week), animal-assisted intervention (4 sessions, each comprising 75 min per week). See Figure 1 . It is recognized that the integrative therapy method, including nature-based therapy, has a good impact on the health of patients. Nevertheless, this study focuses on nature-based therapy; therefore, the measurements chosen for this study focus on nature-based therapy.

2.2. Procedure

Nature-based therapy.

The nature-based therapy program for the psychosomatic patients at the GKH takes place three times a week, with one hour allocated for each session. All sessions take place outside, either in the garden (twice a week) or in the forest (once a week). The therapy garden of the GKH is located on the hospital grounds at a distance of about 150 m from the patients’ house. The hospital is partly surrounded by forest in which the forest therapy units take place. The nature-based therapy takes place in a group setting and comprises a maximum of 12 psychosomatic patients. The group is constantly changing: each week, approximately two participants start their stay at the hospital and two leave the group by ending their stay.

Each nature-based therapy session in the garden starts in the back corner of the garden, hidden underneath huge chestnut trees with everyone sitting on logs in a circle (see Figure 2 ). The trained nature-based therapist quotes a self-written poem matching the topics, which are specific to the patients in the group. The specific issues were discussed in the therapist meetings held by the transdisciplinary team of caregivers. Following this, the nature-based therapist connects the poem’s content with the topics, including, why the patients are here and their struggles. The therapist also added his own wisdom, referring to his coping strategies and everyday uplifting positive thoughts. This is a way to address the patients’ struggles and foster an acceptance of destigmatizing the patients’ diagnoses and disorders. It is also a way to ensure that everyone feels seen, heard, and accepted as they are. Moreover, this approach supports and enhances practices of self-love.

The circle of logs where each nature-based therapy session starts is in the back of the garden. Image by: Lilly Joschko ©.

Each nature-based therapy session in the forest starts with a walk all together from the patients’ house into the forest at the clinic area (approximately a 1.5 km walk). The session starts with an opening circle and poems—the same as in the garden. After, there can be group walks among nature with further poems and sharing rounds, land art tasks (e.g., finding and creating a home in nature where every individual feels safe, inviting the therapist or the other clients), etc. At the end is a gathering circle and walk back to the clinic house together.

Nature-based therapy often uses a tool called nature metaphors. They provide analogies and are a simple way to understand complex reasoning, enhance information processing, cognitive flexibility, and the ability to remember and recall information [ 60 ]. Metaphors teach specific skills, such as cognitive restructuring, cognitive rehearsal, and exposure in an engaging way [ 61 ]. Furthermore, the destigmatization of mental health disorders is necessary to seek and participate in mental health care [ 62 ]. In particular, combining metaphors, cognitive flexibility, and reflection on life issues through nature poems might reduce mental health stigma [ 63 ].

After the opening circle of the therapy session with a poem and wisdom from the therapist, possibilities to engage in gardening work are named by the therapist. The activities are used metaphorically as well. For example, grass that grows along the edges of the flower beds could be pulled out by hand. If someone’s topic were to set clear boundaries, this task would suit them. The participants are always informed that if they see a task that could be performed, and they feel like doing it, they are welcome to perform that task directly. The therapist closes the session under the trees, and everyone chooses a task. Nature-based therapy using the NMBC method (Nature, Mind, Body, Community spirit) [ 64 , 65 ] has the same approach, to some extent. Participants gather at the beginning and end of each session around a fire to share stories and experiences. According to this method, the participants are introduced to various nature experiences and stories about plants and animals, with the intention of opening up the participants’ awareness of nature. By gaining more excellent knowledge of and experiences in nature, place-attachment in a natural environment could be more easily built [ 46 ]. Through storytelling, the participants can also build social cohesion in the group [ 66 ], and it provides new concepts and paradigms for healthy behavior [ 67 ].

During the nature-based therapy session, the therapist does some gardening work as well. Additionally, he keeps an eye on the patients to see if everything is going well. The therapist is always there to answer questions and give advice regarding the tasks. Moreover, he asks the patients if everything is going well and offers the possibility to engage in talks and other tasks, too. At the end of the session, he asks the patients to clean up their space and return the tools they used. Thus, after the one-hour therapy session, everyone goes back together to the psychosomatic house in the clinic where they are staying. In general, the patients are welcome to spend their free time in the garden as well and carry out watering over the weekend when it is a hot day. However, good care is taken to ensure that the tasks are always freely chosen and are performed on a voluntary basis. After the stay of 4–6 weeks, each patient receives a letter from the therapist to take home. There, he or she quotes a poem that suits the feeling and the personal situation of the specific patient. Additionally, the therapist writes some personal words of support and well wishes for them to take home.

Overall, the intervention is an invitation that helped the patients to feel a connection with nature, to use nature as an illustration of transformation, and struggles, as well as a positive example. The analogy is that plants are seeded, grow, die, rest in the winter, and then grow again in the summer.

2.3. Outcomes

Qualitative data were collected via open questions in the questionnaire and participant observations, such as talks during the nature-based therapy with the researcher and the therapist. After each session, the researchers wrote down what they saw, how participants behaved, talks with the clients, little quotes of what they said and which activities they joined, and which poems were cited at the beginning of the session.

All quantitative outcomes were collected with standardized and validated questionnaires. The primary outcome is the subscale ‘mental well-being’ (German “psychologisches Wohlbefinden” (WOHL)), taken from the HEALTH-49 questionnaire [ 68 ]. Secondary outcomes are the connectedness to the nature scale (CNS) [ 42 ] and the Patients Health Questionnaire (PHQ-D) [ 69 ]. In the following sections, each questionnaire is described in detail.

Questionnaires

Demographic data, including age, gender, and diagnosis, were obtained during the baseline of the nature-based therapy. The self-rated questionnaires (baseline- and post-questionnaire) used for this research comprised four standardized, self-completed questionnaires and diagnostic instruments to measure the outcomes of nature-based therapy in terms of connectedness to nature, as well as some questions to evaluate the effectiveness of nature-based therapy as one part of the integrative approach.

WOHL. The subscale ‘mental well-being’ (WOHL) of the HEALTH-49 questionnaire, German version [ 68 , 70 ], was used. The test has been shown to meet the following Q criteria: practicability, dimensionality, reliability, validity, and sensitivity to change (ibid). It consists of five questions, using a 5-point Likert scale from 0 to 4. The higher the sum score, the better the mental health of the patients. The sum score range is from 0 to 20. Cut off is 1.821 and the critical difference is 0.628.

CNS. The Connectedness to nature scale (CNS) [ 42 ] comprises 13 questions, answered on a 7-point Likert scale. In this study, it is used to examine an individual’s connectedness to nature. The scale has been demonstrated to have good psychometric properties, such as validity and reliability. Higher scores on the scale indicated a higher connectedness to nature.

PHQ-D. The German version of the Patients Health Questionnaire (PHQ-D) [ 69 ] was used to classify the diagnoses of the psychosomatic patients. The PHQ-D is a valid, effective, and well-accepted scale. Specifically, it classifies various disorders. The subscales used in this study are for: depression (PHQ-9 [ 71 ]), somatoform disorders (PHQ-15 [ 72 ]), and stress. All three use a 4-point Likert scale. The depression subscale has 9 items and classifies depression with a total score from 0, indicating no depression, to 27, indicating severe depression. A score of five or more indicates mild depression, from 10 to 14 moderate, from 15 to 19 moderate-severe, and above 20 severe depression. The Somatoform disorder subscale has 13 items and uses a total score from 0 to 30. Scores of 5, 10, and 15 represent cutoff points for low, medium, and high somatic symptom severity in the PHQ-15. The stress subscale comprises ten items, with the scores ranging from 0 to 20. The higher the score, the more severe the impairment.

The participants’ self-assessment of the effectiveness of the nature-based therapy was evaluated with the post-questionnaire (for post-testing). It was created for this research to evaluate the effectiveness of nature-based therapy. For this study, eight questions were used to focus on the nature-based therapy that takes place at GKH. They are embedded in the overall “Questionnaire to evaluate the effectiveness of anthroposophical medical complex treatment from the patient’s perspective,” created by the ‘Working Group integrative and anthroposophical medicine,’ from the Institute of Social Medicine, Epidemiology, and Health Economics at the Charité-Universitätsmedizin, in Berlin. The two overall questions about the effectiveness of and satisfaction with nature-based therapy used a 5-pointLikert scale from very (5 points) to not effective (2 points), including not applicable (1 point). The other, more specific, six questions were answered by a 6-pointLikert scale from fully agree (6 points) to disagree (2 points) and not applicable (1 point). The questions focus on positive improvement on mood level, bodily level, soul level, on grievance, on contact with other people, and on coping with problems and illnesses. “Soul level” is a concept used in counseling [ 73 ], psychotherapy [ 74 ], and nursing [ 75 ], as a holistic concept of consciousness and being. Tucakovic [ 75 ] describes being as a function of the soul. A higher degree of soul level can be described as a higher function of a person’s being, presence, or consciousness. The questionnaire will also be used for further investigations for the research institute and the hospital, even after the data collection for this study is completed.

Attention was paid to using simple and clear language in the questionnaire following the guidelines of Statistics Sweden (2004) ‘Design your questions right’ [ 76 ]. Consideration was also taken to double the necessary pre- and post-questions and to not assess further unsuitable questions twice.

2.4. Statistical Analysis

Given that this was a pilot observational study, the sample size was not calculated. All results are considered exploratory. In addition to descriptive results, t -tests were performed for the before/after comparisons of the nature-based therapy outcomes. All outcomes were reported with pre- and post-nature-based therapy results with false discovery rate correction for multiple testing (q value).

Two linear mixed model analyses were performed for the main analysis. The first analysis included a base model with only the treatment effect as a predictor of mental well-being (WOHL subscale). The second model then included the secondary outcomes as predictors (CNS and PHQ subscales).

Both models included the participant’s ID as a random effect (39–41). Two models were used to better differentiate the effect of secondary outcomes (model 2) from the main effect (model 1). In order to investigate the influence of different covariates, such as depression or anxiety disorder, on the success of the AMT, these were included as covariates in the multivariate mixed effect analyses. Fit measures are reported as well (AIC, BIC, RMSE, Sigma, and ICC).

Analyses were conducted using the R Statistical language (version 4.1.0; R Core Team, Vienna, Austria, 2021) with RStudio Version 1.4.1717 on macOS 12.0.1, using the most recent versions of the R packages: tidyverse, lme4, ggstatsplot, ggeffects, sjPlot, gtsummary. A 5% significance level was set for the statistical analyses [ 77 , 78 , 79 , 80 , 81 , 82 ].

2.5. Qualitative Data Analysis

The explorative open questions answered by the patients in the questionnaire and researcher’s field notes (such as observations, quotes, talks with patients from the sessions, and talks and observations from the therapists) were collected and transcribed into one document. This document was treated as one type of data, although the open questions from the questionnaire were given more weight and used as direct citations in the discussion section. The first step was to collect all the material and sort it into different topics: open questions from the questionnaire, observations from the researcher, observations from the therapist, and notes from the notebook regarding poems and talks during the therapy. Thereafter, all the material was translated from German into English. Next was the stage of inductive coding which involved reading and re-reading the material, connecting the emerging topics and themes based on the thematic psychology approach [ 83 ]. The realistic psychology approach was the basis of making meaning out of the bits and pieces collected. A narrative analysis was then written from the researchers’ perspective to provide new meaning by synthesizing the experiences and sessions into a coherent whole [ 84 ]. The key meanings, themes, and ideas obtained from the qualitative data analysis were triangulated with the results of the quantitative analysis in the discussion. It is acknowledged that the researcher’s perspective is highly important and a lot of reflection is needed to observe as objectively as possible [ 55 ]. The narrative approach is also influenced by symbolic interactionism, which investigates how meanings are constructed by individuals (in this case, the patients) within their social and personal world [ 85 ]. An additional point of view is given to pluralistic knowledge, which means that we shift the paradigm toward multidimensional mechanisms that take place at the same time [ 86 ]. It is not about one factor that influenced the health of the patients; rather, it is about finding out the different mechanisms at work during nature-based therapy, as experienced by the patients.

3.1. Sample Description

A total of 20 patients (18–27 years old) participated in the study. One person dropped out during the baseline collection, after giving their consent to participate in the study. Thereafter, 19 participants remained (see Figure 3 ).

CONSORT flow-diagram: transparent records of participants for the study.

Specifically, 16 female and three male patients took part in the baseline data collection (see Table 1 ). Their average age was 21 years. Not all patients concluded their four–six-week rehabilitation program because they broke the house and/or COVID-19 regulations. Consequently, three female participants did not take part in the post-testing, since they had to leave the hospital earlier.

Demographic data (age and gender) of the patients divided into the baseline and post-testing conditions.

All patients received a diagnosis of depression (mild–severe) with the German version of the patient’s health questionnaire (PHD-Q) [ 69 ]. Most patients (63%) were deemed to have a pronounced and severe depression (n = 12). Other additional diagnoses are somatoform disorders, insomnia, acrophobia, anxiety disorders, social phobia, post-traumatic stress disorder (PTSD), anorexia, obsessive-compulsive disorders, panic disorder, and bulimia. Patients in the psychosomatic clinic at the GKH can be admitted either by their general practitioner (resident physician) or by their own request.

3.2. Quantitative Results

To evaluate the effect of the nature-based therapy, the paired t -test was performed (results, see Table 2 ). The paired t -test tested the difference between the mean of the baseline and post-condition of mental well-being (WOHL) and for all the secondary outcomes. The paired t -test, testing the difference between the WOHL baseline (1.05) and WOHL post-testing (1.60; mean difference = 0.55), suggests that the effect is statistically significant and large ( p < 0.001; Cohen’s d = −1.04, see Table 2 ). The difference of 0.55 measured here is below the critical difference of 0.68 that is given by the author for clinical relevance.

Paired samples t -test of the baseline and post-testing comparison.

The difference between the CNS baseline (3.91) and mean CNS post-testing (4.37; mean difference = 0.45, p = 0.010) suggests that the effect is statistically significant and medium (Cohen’s d = −0.74, see Table 2 ).

The paired t -test, testing the difference in depression between the PHQ-9 baseline (16.94) and the PHQ-9 post-testing (12.94; mean difference = 3.31), suggests that the effect is statistically significant and medium ( p = 0.044; Cohen’s d = 0.55, see Table 2 ). Even if the effect for depression is just statistically significant here and the mean score changes from moderate-severe at baseline to moderate in post-testing, the reduction of 3.31 points in the PHQ-9 is not a clinically relevant reduction in the depression scores.

PHQ scores for the subscales for stress and somatoform disorders are both non-significant differences with small and very small effects (see Table 2 ).

For our main analysis, the effect of nature-based therapy on mental well-being, we fitted two linear mixed models (estimated using REML and nloptwrap optimizer) to predict mental well-being (WOHL) with treatment in model 1. Both models included patients’ ID as a random effect. The total explanatory power of base model 1 predicting mental well-being only by treatment is substantial (conditional R 2 = 0.61), and the part related to the fixed effects alone (marginal R 2 ) is 0.21. The model’s intercept, corresponding to treatment = baseline, is at 1.05 (95% CI [0.80, 1.31], t(31) = 8.41, p < 0.001). The effect of treatment [post] within this base model 1 is statistically significant and positive (beta = 0.55, 95% CI [0.28, 0.82], t(31) = 4.12, p < 0.001; Std. beta = 0.92, 95% CI [0.46, 1.37]). As could also be seen from the pre/post comparisons of the measured outcomes, base model 1 of the liner mixed effect analysis reflects the result. The inpatient stay has a positive effect on the mental well-being of the patients, measured with the subscale WOHL of the HEALTH-49.

To distinguish the effect of nature-based therapy more specifically, we included the effect of connectedness to nature with the other secondary outcomes in our second linear mixed model predicting mental well-being (see Table 3 and Figure 4 ). While having patients’ ID as a random effect included (estimated using REML and nloptwrap optimizer), all others are fixed effects predicting mental well-being (WOHL) with treatment, CNS, PHQ-9, PHQ stress scale, and somatoform disorders (PHQ-15). The second model’s total explanatory power is substantial (conditional R 2 = 0.74, Table 3 ), and the part related to the fixed effects alone (marginal R 2 ) is 0.35. The model’s intercept, corresponding to treatment = baseline, CNS = 0, PHQD = 0, PHQS = 0, and PHQSO = 0, is at −0.21 (see Table 3 ). Within this second model, the effect of Treatment [post] is statistically significant and positive (beta = 0.46, p = 0.003; see Table 3 ). This effect suggests that treatment was effective in helping patients gain a higher mental well-being score in the WOHL subscale of HEALTH-49 during their inpatient stay in the GKH hospital (see Table 3 ). Patients’ connectedness to nature (beta = −0.13, p = 0.191), the depression score measured with the PHQ-9 (beta = −0.03, p = 0.265), and the stress scale from PHQ-D (beta = −0.04, p = 0.194) are statistically non-significant and negative. The effect of somatoform disorder (PHQ-15) is statistically non-significant and positive (beta = 0.00, p = 0.895). All secondary outcomes have no statistically significant effect on predicting mental well-being in this group of patients. Patients’ connectedness to nature increased during their stay in the hospital (see Table 2 ), but it has a non-significant and very small negative effect in predicting mental well-being. All secondary outcomes have no noteworthy correlations with all other outcomes, thus having no impact on the linear mixed effect analysis and additionally also no noticeable interactions. Despite all this, the secondary outcomes contribute to an overall improved second model (Chisq = 11.432, df = 4, p = 0.022, AIC = 54.691, BIC = 67.134, LogLik = −19.346).

Linear mixed effects analysis. Model 2 predicting mental well-being (WOHL) by Treatment, Connectedness to Nature (CNS), and PHQ-D subscales for depression, somatoform disorders, and stress.

Linear Mixed Effects Analysis. Model 2 predicting mental well-being (WOHL) by Treatment, Connectedness to Nature Scale (CNS), and PHQ-D subscales (PHQ-9, PHQ-15, and stress).

Random effect: patients’ ID. Fixed effects: Treatment, Connectedness to Nature Scale (CNS), Depression (PHQ-9), Stress (PHQ-D), and Somatoform Disorders (PHQ-15). Standardized parameters were obtained by fitting the model on a standardized version of the dataset. 95% Confidence Intervals (CIs) and p -values were computed using a Wald t-distribution approximation.

The ’Evaluation of the nature-based therapy from the patient’s perspective’ was filled in by 15 participants. All participants experienced the nature-based therapy as effective (see Figure 5 ). Specifically, 86.66% experienced the nature-based therapy as satisfactory, while 53.32% witnessed the nature-based therapy as supportive, and self-reported an improvement in their condition. Furthermore, 40% experienced an improvement on a bodily level, 93.33% encountered enhancement on a mood level, and everyone experienced improvement on a soul level. Moreover, 46.66% felt an enrichment in their well-being, while 53.33% experienced that their contact with other people had improved. In addition, 86.66% encountered development in coping with problems and illnesses. Interestingly, in this part of the questionnaire, most individuals (87%) felt they had improved in coping with problems and illness through nature-based intervention (see Figure 5 ).

Experienced effectiveness, satisfaction, and improvements from nature-based therapy based on the self-rated post-testing questionnaire.

3.3. Qualitative Results

Patients described that they felt safe in the garden because of the environment and the therapist and researcher who was setting up the place. The therapist was described as being empathetic, accepting the patients as they were in the moment when they sought help, meeting them with unconditional valuation, and fostering their connection to themselves while fostering their nature connection. The therapist created an environment where everyone felt safe, seen, heard, inspired, encouraged to explore, and truly accepted as they were. It was not about performance; rather, it was about being. It was about re-connecting with oneself, i.e., connecting with one’s own feelings, learning self-acceptance, and self-love out of the numbness they experienced before. One client said, “Normally, I withdraw in nature. I felt connected, but now, it makes me realize that this blunt feeling is there.” There were no expectations about how they should be, what had to be included in the session, or what had to be accomplished.

Nature-based therapy was about the process of doing, exploring the slowness, re-connection to oneself, and feelings in general, but also joy. The patients could choose what tasks they wanted to do themselves, individually and at their own pace. This atmosphere of acceptance and openness was facilitated by the staff and the environment. The therapist said, “Through nature-based therapy, the patients learn acceptance with impermanence. Change in the garden and in the self.” Additionally, the therapist encouraged the patients at the beginning of each session to reflect on the topic of the poem. This was achieved indirectly—without a task or any demands. It was achieved with a high degree of freedom. It was achieved through inspiration from the poem and the experiences the therapist shared from his own life. The therapist’s calm attitude and the garden revealed fascination and recreation. The therapist acted as the door opener for the clients to look at nature and themselves in a more reflective, metaphorical, and accepting way, being in the here and now, mindful through linking nature with human behavior. For example, one poem was about walking through the thicket and bushwhack and mosquito infestation. Along the way, losing courage, getting lost, not knowing the way, back or forth, becoming afraid. However, in the end, arriving in passing. After quoting the poem, the therapist said, “It is a challenge to be here, but it is also an invitation to change; it can always be the next step to leave the thicket, to arrive. It is worth going further”. With these words, he heartened the patients; he was full of acceptance, courage, and love. He destigmatized their choice to go to the psychosomatic clinic because they felt lost.

The activity for the day was to sow seeds, which can be interpreted as inspiration for change—the next step to leave the thicket. The process of recovery and starting something new. The seeds of inspiration. This special interplay of so many layers of reinforced recovery was described by one patient as: “Especially important and formative for me were and are the talks at the beginning where many topics are conveyed, particularly empathetically and skillfully, which are sometimes general, but formulated so that everyone can take something for themselves. I was able to rethink many things and took away a lot of courage and confirmation. The honesty, attentiveness, empathy, courage that I always encountered have enriched me very much.”

The poems and the gardening work have been seen as repetitive to reflect on one’s own topics from psychotherapy, possibly directly making changes to one’s behavior. One patient wrote: “I particularly remember the silence after a poem, where everyone was completely with themselves for a moment.”

Through this holistic approach in the garden, the therapist fostered the participants’ connectedness to nature. Some had none; they never felt a connection to nature; and they never stopped to just look at nature, to be there, to use the time to reflect. Some were also afraid of being in nature because they did not feel safe outside at all. However, through the therapy, one patient told me that from now on she would take time for herself in nature. To sit and relax. Just watching the green space, doing nothing, and potentially thinking about the therapy and the garden at the hospital.

Many patients asked for a plant they could take home with them—to have something life-like from the clinic. A visible change, a trophy, a memory of lessons learned. To remember to integrate them into their everyday life. Patients often said, “The plant will remind me to take care of not only the plant but also myself.” It is a way to remember self-care, self-love, and self-acceptance. Furthermore, patients developed a curiosity and a new interest in plants. They approached the researcher and the therapist to ask about the names of the plants and used their limited online time to research the plants and their needs.

Overall, nature-based therapy helped patients to trust in change and the small changes that are within us—not directly visible. Taking plants or a tree pit from therapy, (which was connected to a poem and wisdom that everything we learn is stored within us) with them fostered their transfer effect. It allowed them to transfer lessons learned from the therapy into their everyday life at home. One patient wrote: “When I go home and I have the feeling that I didn’t learn anything, or I fall back into my old habits—the words of the therapist and caregivers come to use and I carry them with me—consciously or unconsciously. I created new rings as well, and they won’t disappear.”

4. Discussion

Our aim was to investigate the relationships between nature-based therapy, mental health, and individuals’ connectedness to nature. Specifically, the first hypothesis was to investigate if nature-based therapy has a positive impact on individuals’ mental health. The results from the WOHL support our hypothesis that there is a change over time in mental well-being in psychosomatic patients through nature-based therapy (see Table 2 ). Receiving nature-based therapy increased mental well-being significantly. Although not clinically relevant, the results also showed that self-reported symptoms of depression decreased significantly, as measured by the PHQ-9. The severity of the diagnoses of depression decreased: through their therapy program (including nature-based therapy), the depression scores decreased. During the baseline, 12 individuals had pronounced and severe depression. At the post-testing, seven individuals continued to have pronounced and heavy depression scores. These results indicate that nature-based therapy might decrease depression severity. On the whole, the following three scores: depressiveness, somatoform disorders, and stress decreased through the treatment. From baseline to post-testing, the mean for all three scores decreased. Thus, it is assumed that the therapy all patients received, including nature-based therapy, might have a positive effect on these three disorders. These changes might be due to the treatment the patients received in nature, but might also be a side effect from the other therapy sessions and activities that clients received. There was no evaluation of the overall complex treatment the clients received; therefore, there is no conclusion about which treatment helped whom the most. This could be further investigated. However, results from the participants’ self-assessment questionnaire on the effectiveness of nature-based therapy showed that they considered the therapy to be effective, not least regarding mood. This effectiveness of nature-based therapy goes in line with the findings from other nature-based intervention studies [ 21 , 36 , 38 , 39 , 87 , 88 , 89 , 90 , 91 , 92 ].

Our second hypothesis was to investigate if nature-based therapy has a positive impact on individuals’ connectedness to nature. The results from the connectedness to nature scale (CNS) support our hypothesis that there is a change over time regarding connectedness to nature in psychosomatic patients through nature-based therapy (see Table 2 ). Receiving nature-based therapy increased connectedness to nature significantly. The natural environment itself and the therapy together could have fostered this connectedness. The Calm and Connection Theory posits that environments and situations that trigger a release of oxytocin can lead to promoting connectedness to a natural environment. Studies have found that for nature-based therapy to work, participants first need to find a place they like, where they can find security and want to return to. They also need to find opportunities for meaningful activities where they feel they can accomplish something, feel satisfaction, and joy and that they can grow [ 20 , 21 ]. According to the Calm and Connection Theory, these conditions provide an opportunity for a release of oxytocin, which reduces stress levels, while levels of trust and well-being increase, which, in turn, promotes attachment, or connectedness, to the place [ 50 ]. According to the Supportive Environment Theory [ 21 ], nature-based therapy must include three supportive environments: a physical environment, a social environment, and a cultural environment. The cultural environment is conveyed through language and activities, as well as through symbols in the environment, for example, in the expression of the surrounding nature and how the garden is designed. The supportive environments should also include a gradient so that they support people with very poor coping resources to those with growing resources. Moreover, the therapy must be led by a person with great empathy and sensitivity to the participants’ needs [ 21 ]. If nature-based therapy is carried out with such conditions, health-promoting effects, social ability, and the ability to develop coping skills will be promoted [ 50 ]. Studies also show that in such nature-based therapy settings, patients experienced nature-based rehabilitation as a meaningful occupation [ 67 ] and the place as a restorative environment [ 26 ]. The restorative environment was experienced as very important for their recovery process. This was also true for the offered activities, which were adaptable to the individual needs of the patients. They could be passively engaged (inner involvement) or actively outgoing [ 26 ]. A similar structure was offered in the nature-based therapy program that the current study investigated.

Themes from the qualitative interviews showed that the participants considered that the nature-based activities and the setting itself caused health-promoting effects. Different gardening activities were offered, and everyone was allowed to be themselves, to show their inner self—be authentic and engage in the activity they liked. The therapy program might have fostered the individuals’ meaningfulness and connection. One patient wrote what she liked in the nature-based therapy was, “The feeling of doing something and above all doing something meaningful and good, which helps me and nature”.

“Meaningfulness, in contrast to depression, is understood as a developmental motive, referring to a human’s need of being in the world and experiencing a sense of purpose in life” [ 45 ] (p. 385).

Finding meaning in life is important for one’s well-being and might be one of the most important aspects of living [ 93 ], and it is the core of the concept of salutogenesis [ 94 , 95 ]. Garden activities can give meaning [ 21 , 35 , 88 , 94 , 95 , 96 ]. This might have an evolutionary explanation [ 97 ], since back in the day, gardening was necessary for survival, as it provided food for one’s social group or family. The results from the current study on improvements in well-being (see Table 2 ) and the effectiveness of the nature-based therapy (see Figure 5 ) support the findings from the literature. The majority of patients indicated that their contact with other people has improved during the nature-based therapy (see Figure 5 ). The explanation for an increased connectedness might be the therapy group setting, where people feel connected as a group. They do activities together, knowing they are not alone with their disorder. Feeling accepted by others and experiencing social and natural connectedness can support people with mental health problems to integrate socially and improve their communication skills through shared reflection [ 19 , 23 , 50 , 96 ]. Therefore, some of the benefits of nature-based therapy might arise from it increasing social cohesion. Additionally, this might be a transfer effect, since the nature connection improved and through this, the general ability to connect with other people as well. Through the different nature-based therapy sessions, it was tremendous to see the patients grow as well as the plants. Most of them were quiet in the beginning, withdrawn like a seed in the ground. However, with more time in the rehabilitation process, they started being more outgoing, and they started to sprout and grow. They asked for activities to start, chose themselves what they wanted to do in the garden, and found the individual projects they were happy to work on—started blooming. They found motivation in doing gardening work, even if they did not like it from the beginning. One client said, “I would never have thought so, but garden activities are really great, and I like doing them.” These observations from the researcher are congruent with the findings from Pálsdóttir et al. [ 21 ]. The researcher found that initially the clients are more withdrawn, and later on show active participation. This effect might be explained by a quote from Berger: “We never look at just one thing; we are always looking at the relation between things and ourselves” [ 98 ]. He describes that nature might have served as a mirror for patients during nature-based therapy. One patient said that the cycles from nature reminded them that they also need time for themselves to retreat. These results are also found in other studies, where events in nature are interpreted symbolically by participants in nature-based therapy and lead to reflections on their own choices in life [ 20 , 21 ]. Moreover, results from the participants’ self-assessment questionnaire on the effectiveness of nature-based therapy showed that they considered the therapy to be effective in learning how to cope with problems and illness (see Figure 5 ). A main theme in the qualitative interviews was also that the participants experienced a higher self-efficacy and self-acceptance through nature-based intervention. The nature-based therapist was highly praised for being empathetic, and reciting interesting poems, and can be seen to have been an eye opener for many. Patients experienced this as valuable since they discovered new interests, experienced self-efficiency, and became inspired to change. One patient said, “I realized that I can be a creator. Through sowing seeds, I realized that I can create and nurture new things with my hands. Influence other lives”. Thus, self-efficiency and self-acceptance might lead to a positive mindset, which is associated with health and well-being (lower levels of inflammation) [ 99 ]. This is consistent with the findings from Pálsdóttir, Grahn, and Persson [ 88 ]. In their research, nature-based rehabilitation led to a positive change in their perceived values of everyday occupation, inspiration for transformation, and a more sustainable lifestyle. Additionally, being outside and being exposed to more light/brightness might lead to increased self-awareness [ 32 ]. Through psychoeducation (part of the integrative therapy program), the clients learn mindfulness practice, which might be an influencing factor in the nature-based therapy as well. The participants learned to be present in the here and now, and thus being able to experience the qualities of nature. This has been shown to be effective in other therapy settings [ 59 , 64 , 65 , 100 ]. It is interesting to look at the finding that everyone felt an improvement on the soul level through nature-based therapy (see Figure 5 ). To our knowledge, no studies have investigated an improvement on people’s soul level in nature-based therapy yet. However, attention has been paid to the connection between people’s soul, their health, and being in nature and gardens [ 101 ]. It is unclear what each patient understood as ‘soul improvement.’ This study makes a connection between spirituality and soul, and we refer to the definition by Brown, Carney, Parrish, and Klem as “[…] a sense of connectedness to a higher power and openness to the infinite beyond human existence and experience” [ 102 ] (pp. 110–111). Research investigating spirituality in mental health found a reduction in mental and emotional illness in individuals with high spirituality [ 102 ]. The World Health Organization has discussed the existential dimension of health, which they define to be based on eight components: spiritual connection, meaning and purpose in life, the experience of awe and wonder, wholeness and integration, spiritual strength, inner peace, hope and optimism, and faith [ 103 ]. Melder [ 103 ] found that people’s contact with nature was one of four factors most often mentioned as meaning-making by the subjects, and this can be linked to a stronger existential dimension in life [ 103 ]. An explanation might be the biophilia hypothesis, which states that human beings come from nature, have an urge to be in nature, and to (re-) connect to nature [ 97 ]. Furthermore, this might be explained by the findings of Sahlin et al. [ 104 ], namely that activities in the garden allowed patients to practice doing one thing at a time, not rushing through things, and allowing oneself to take breaks [ 104 ]. Moreover, belonging to a social context, since the patients were with other patients with similar diagnoses in the same therapy program and sessions, might have been experienced as supportive, too. Additionally, the transdisciplinary therapist team with the holistic approach might have been vital for developing strategies and tools to better face and manage everyday demands. Altogether, this might lead to an improvement on the soul level—a holistic approach and understanding oneself through connection with nature and others and having a place in the world.

Something we need to highlight is the importance of the therapist. Sometimes a skilled therapist is needed to help in the rehabilitation process, to be a catalyst, and open one’s eyes, as the participants sometimes put it. Sahlin et al. [ 104 , 105 ] mention that the botanist in the rehabilitation garden of Gröna Rehab in Gothenburg allows the participants to discover nature during walks in the nearby nature reserve. Each participant has their own magnifying glass to help them. The botanist invites participants to use it and discover through the magnifying glass the nuances and riches hidden in flowers, mosses, butterflies, etc. They experience a grandeur, awe, and wonder in nature that touches them deeply and involves their own situation on an existential level. It includes a forgiving attitude toward both the environment and themselves, gives them hope, and starts new coping strategies [ 104 , 105 ]. In the same way, the therapist in this study helps the participants to look at nature in a new way, such as by interpreting annual rings symbolically. Experiencing the greatness and beauty, being deeply touched, and feeling trust in nature, an awe, a connection, and perhaps love, can, according to some controlled studies, give the participants strength and courage, as well as give new perspectives on themselves and existence [ 106 , 107 ]. Oxytocin is sometimes called the hormone of love, and the Calm and Connection Theory suggests that the oxytocinergic system is activated in a very powerful way when a person feels security, attraction to, and connectedness to natural environments, which affects the individual on a deeper level [ 50 ]. Accordingly, this awe, attraction to, and perhaps the love of the natural environment can, mediated by the oxytocinergic system, lead the persons to transcend their way of being and thinking, about both their selves and existence. It can lead to a change in their internal working model (that is, their routine ways of feeling, thinking, and acting), making them understand how to deal with life. This, in turn, leads to improvements in one’s physical and mental health [ 91 , 108 , 109 ].

With our third hypothesis, we intended to investigate whether there is a difference in the improvement of psychological well-being in patients with low or high connectedness to nature after nature-based therapy. Does connectedness to nature improve mental well-being? The question as to whether a nature lover (means higher connectedness to nature at the beginning of the therapy) recovers better from nature-based therapy remains unanswered. No statistically significant differences were found in the comparison. Connectedness to nature had no influence in predicting WOHL in the linear mixed effect analysis. Thus, there was no evidence for the third hypothesis, namely that there would be a difference in the improvement between individuals scoring low/high on connectedness to nature through nature-based therapy. These results might be due to a very small sample size, resulting in low statistical power. Nevertheless, a trend is visible when comparing WOHL in the baseline and post-testing. This could be investigated through further research. It is possible that individuals scoring low on connectedness to nature have a bigger chance of improvement than the ones already scoring high on connectedness to nature.

More females (13–16, ≙ 81–84%) than males (3 ≙ 15–18%) participated in the two measurements (baseline and post-testing) (see Table 1 ). This is consistent with the disease contribution among gender. More females than males have a diagnosis of depression [ 7 ].

The frequency of participation in nature-based therapy might have influenced the outcome (dose-respond relationship). Since individual psychotherapy sessions took place during nature-based therapy, sometimes patients could not attend nature-based therapy. Furthermore, the length of stay varied among the patients (some stayed four, some up to six weeks). Nevertheless, the frequency of attendance was recorded per patient. This was evaluated, revealing that there were no big differences in the participation of nature-based therapy from patients during their stay. They attended between 9–12 sessions during their stay.

It is essential to focus on young individuals’ health and well-being as the older they get, the more established (unhealthy) their routines become, resulting in a lifestyle that may be unhealthy [ 10 ]. Additionally, the costs of healthcare increase if those with long-term problems are not treated directly [ 9 ]. Moreover, in young adults, severe depression can lead to suicide, the fourth leading cause of death in 15–29year-olds [ 5 ]. Helping individuals at an early stage of depression might lead to a more fulfilled life for them and may lead to an uplifting snowball effect for their (social) surrounding. Furthermore, healthcare costs might stay low when the root cause of a problem is treated directly [ 9 ]. Consequently, less time might be needed to treat the other side effects that may be leading to unhealthy habits.

Limitations

This study gives the first insights into nature-based therapy within the integrative therapy program at the GKH for psychosomatic patients, but many questions remain unanswered.

This study is a pilot study with a pre/post-testing design without a control group. This study design was deliberately chosen for a pilot study because it is not possible and reasonable to separate nature-based therapy as a single element at this stage. Due to the limited design of the study, it is not possible to highlight the nature-based therapy and its independent effect without the other therapy elements of the integrative therapy program. Furthermore, many other confounders can explain the effects found. In this case, to investigate an apparent effect of the nature-based therapy, the control group would receive all parts except the nature-based therapy. Andrews [ 110 ] maintained that the randomized controlled trial design is demanding to use in rehabilitation research and that other strategies can provide equally safe or safer results. In addition, Graham et al. [ 111 ] suggest smaller projects with a clear focus on individual participants as a good research strategy in rehabilitation research. Because they have many benefits, it has been recommended to use quasi-natural experiments more often in rehabilitation research. Among other things, ethical problems are reduced, and the result gives a fairer picture of how real rehabilitation works [ 112 , 113 ]. It would, therefore, be useful to conduct further studies with a more sophisticated study design including a control group, preferably as natural experiments as a form of randomization. The weather influenced the nature-based intervention. During the time of data collection, through mixed methods from May until August, the temperature was warm, with mainly sunny days during the therapy. It remains unclear how the weather influenced the outcome of this research. Further investigations in that direction are needed in future research.

Every person’s perspective with regard to their individual, cultural and geographical backgrounds, including mental state of mind, physical ability, emotional awareness and regulation ability, gender, family background, socio-economic factors, character (e.g., extrovert vs. introvert), as well as possible stigma for the disorders and individual’s spirituality influences the nature-based therapy. Additionally, past experiences with gardens, forests, and nature, and time spent in nature (before and after the therapy) have to be considered. The influencing factor of each person being an individual and therefore the group climate must be considered. The group climate questionnaire [ 114 ] could be used in further research to reveal more insights into the group processes and dynamics in group therapy at work. The time an individual spent at a place and the place attachment that occurs should be considered to influence the outcome, too. Moreover, investigating how the participants use the garden (also on their own, when there is no therapy) would give more insights into the processes (place attachment) and understanding who experienced what as a supportive environment.

The influence of the therapist, the offered activities (the therapy program), as well as the design and organization of the garden, the season, and the time during the day when the nature-based therapy takes place, have to be considered. These circumstances make it particularly difficult to compare the different nature-based therapy sessions and programs.

It is suggested that further studies on nature-based therapy have a longer duration [ 114 ] and investigate the underlying influencing factors from connectedness to nature (the feeling of connectedness within the group, spirituality, and meaningfulness of the activity in the garden).

Further research could also investigate the different qualities of the two places (the forest and the garden) of the nature-based therapy taking place at the GKH. Research suggests that both places have different qualities, and the combination is suggested to be promising for therapy outcomes [ 89 , 115 , 116 ]. Nevertheless, these are expectations that might apply to the places at GKH as well. The perception of these places needs further evaluation in further research with, for example, the PSD [ 21 ], the evaluation tool suggested by Bengtsson and Grahn [ 25 ] or Tudaor [ 117 ], since currently, there is no evaluation from the clients’ perspective at the GKH.

Nature-based therapy might have fostered the transfer effect from the clinic to everyday life. The qualitative results revealed that some patients took a trophy home, a plant, a tree pit, and a poem from the therapist. This could lead to a longitudinal positive effect on mental health in patients and should be investigated in further studies via a follow-up study design. Additionally, this could provide further explanation on how sustainable/stable these effects of mental health and connectedness to nature are. Did the transfer of the integrative therapy program into everyday life happen? A longitudinal multiple assessment design with follow-up assessments is suggested (e.g., one baseline before attending the intervention, a follow-up at the GKH, and one assessment after the last intervention at the GKH, and follow-up assessments at home after one month, six and 12 months after the intervention—to also be able to investigate the long-term effects of the therapy approach). A control group without nature-based therapy but including all other therapy elements is also suggested.

No gender-specific results could be revealed since mainly women participated in this research, and one trans person (not visible in the gender questionnaire).

5. Conclusions

This research gives insight into the influences of the integrative therapy program with a focus on nature-based therapy on the health and well-being of psychosomatic patients. The aim was to better understand how connectedness to nature influences mental well-being and to develop nature-based therapy programs. Another aim was to promote the health effects that these little garden spaces have on patients. Indeed, the results of this study indicate that nature-based therapy as part of the integrative treatment can be an effective treatment for psychosomatic disorders. Furthermore, the results show that connectedness to nature and mental well-being are connected in psychosomatic patients, and both significantly improve over time. Effectiveness, satisfaction, and improvements on the mood and soul level, well-being, contact with other people, and coping with problems and ill health from the patients’ perspective are reported.

To conclude, this data contributes to the positive effect of integrative therapy concepts and that it is possibly influenced by nature-based therapy. Moreover, it highlights the need for such therapy to be a publicly funded service, accessible and beneficial for all. To our current knowledge, no studies were found that investigated connectedness to nature in the German population, nor in the context of nature-based intervention in psychosomatic patients. To promote the conclusions from this study, further research, for example, with a mixed methodology (interviews as a qualitative approach), a bigger sample size, a control group (RCT), and a longer period of time (ideally, several years), with focus on a cumulative, specific investigation on all therapy elements from the integrative therapy, is needed. Especially, it is important to find out who benefits the most from nature-based therapy (patients with initially low/high connectedness to nature). Moreover, the qualities of the natural environment where the nature-based therapy takes place have to be taken into account from the patients’ perspective as well.

Acknowledgments

Our gratitude to all the participants who shared their experience from the NBI as well as the nature-based therapist and the psychosomatic therapist and the medical team. Our sincere gratitude to the reviewers for their valuable comments on the manuscript. We acknowledge financial support from the Open Access Publication Fund of Charité—Universitätsmedizin Berlin and the German Research Foundation (DFG).

Funding Statement

This research received no external funding.

Author Contributions

Conceptualization, L.J., A.M.P., P.G. and M.H.; Methodology, L.J., A.M.P., P.G. and M.H.; Validation, A.M.P., P.G. and M.H.; Formal analysis, L.J. and M.H.; Investigation, L.J.; Resources, M.H.; Data curation, L.J., A.M.P. and M.H.; Writing—original draft, L.J.; Writing—review & editing, L.J., A.M.P., P.G. and M.H.; Visualization, L.J. and M.H.; Supervision, A.M.P., P.G. and M.H.; Project administration, M.H. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki, and it was approved by the Ethical Committee of Charité-Universitätsmedizin Berlin for studies involving humans. This study is part of the overall study ‘Evaluation der Anthroposophischen komplexziffer im DRG System (EVAL 26)’ (English translation: ‘Evaluation of the anthroposophical complex digit in the DRG system’ (EVAL 26)) with the ethic vote number EA2/089/19 from 31 May 2019.

Informed Consent Statement

Written and informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Conflicts of interest.

The authors declare no conflict of interest.

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Guest Essay

The Long-Overlooked Molecule That Will Define a Generation of Science

By Thomas Cech

Dr. Cech is a biochemist and the author of the forthcoming book “The Catalyst: RNA and the Quest to Unlock Life’s Deepest Secrets,” from which this essay is adapted.

From E=mc² to splitting the atom to the invention of the transistor, the first half of the 20th century was dominated by breakthroughs in physics.

Then, in the early 1950s, biology began to nudge physics out of the scientific spotlight — and when I say “biology,” what I really mean is DNA. The momentous discovery of the DNA double helix in 1953 more or less ushered in a new era in science that culminated in the Human Genome Project, completed in 2003, which decoded all of our DNA into a biological blueprint of humankind.

DNA has received an immense amount of attention. And while the double helix was certainly groundbreaking in its time, the current generation of scientific history will be defined by a different (and, until recently, lesser-known) molecule — one that I believe will play an even bigger role in furthering our understanding of human life: RNA.

You may remember learning about RNA (ribonucleic acid) back in your high school biology class as the messenger that carries information stored in DNA to instruct the formation of proteins. Such messenger RNA, mRNA for short, recently entered the mainstream conversation thanks to the role they played in the Covid-19 vaccines. But RNA is much more than a messenger, as critical as that function may be.

Other types of RNA, called “noncoding” RNAs, are a tiny biological powerhouse that can help to treat and cure deadly diseases, unlock the potential of the human genome and solve one of the most enduring mysteries of science: explaining the origins of all life on our planet.

Though it is a linchpin of every living thing on Earth, RNA was misunderstood and underappreciated for decades — often dismissed as nothing more than a biochemical backup singer, slaving away in obscurity in the shadows of the diva, DNA. I know that firsthand: I was slaving away in obscurity on its behalf.

In the early 1980s, when I was much younger and most of the promise of RNA was still unimagined, I set up my lab at the University of Colorado, Boulder. After two years of false leads and frustration, my research group discovered that the RNA we’d been studying had catalytic power. This means that the RNA could cut and join biochemical bonds all by itself — the sort of activity that had been thought to be the sole purview of protein enzymes. This gave us a tantalizing glimpse at our deepest origins: If RNA could both hold information and orchestrate the assembly of molecules, it was very likely that the first living things to spring out of the primordial ooze were RNA-based organisms.

That breakthrough at my lab — along with independent observations of RNA catalysis by Sidney Altman at Yale — was recognized with a Nobel Prize in 1989. The attention generated by the prize helped lead to an efflorescence of research that continued to expand our idea of what RNA could do.

In recent years, our understanding of RNA has begun to advance even more rapidly. Since 2000, RNA-related breakthroughs have led to 11 Nobel Prizes. In the same period, the number of scientific journal articles and patents generated annually by RNA research has quadrupled. There are more than 400 RNA-based drugs in development, beyond the ones that are already in use. And in 2022 alone, more than $1 billion in private equity funds was invested in biotechnology start-ups to explore frontiers in RNA research.

What’s driving the RNA age is this molecule’s dazzling versatility. Yes, RNA can store genetic information, just like DNA. As a case in point, many of the viruses (from influenza to Ebola to SARS-CoV-2) that plague us don’t bother with DNA at all; their genes are made of RNA, which suits them perfectly well. But storing information is only the first chapter in RNA’s playbook.

Unlike DNA, RNA plays numerous active roles in living cells. It acts as an enzyme, splicing and dicing other RNA molecules or assembling proteins — the stuff of which all life is built — from amino acid building blocks. It keeps stem cells active and forestalls aging by building out the DNA at the ends of our chromosomes.

RNA discoveries have led to new therapies, such as the use of antisense RNA to help treat children afflicted with the devastating disease spinal muscular atrophy. The mRNA vaccines, which saved millions of lives during the Covid pandemic, are being reformulated to attack other diseases, including some cancers . RNA research may also be helping us rewrite the future; the genetic scissors that give CRISPR its breathtaking power to edit genes are guided to their sites of action by RNAs.

Although most scientists now agree on RNA's bright promise, we are still only beginning to unlock its potential. Consider, for instance, that some 75 percent of the human genome consists of dark matter that is copied into RNAs of unknown function. While some researchers have dismissed this dark matter as junk or noise, I expect it will be the source of even more exciting breakthroughs.

We don’t know yet how many of these possibilities will prove true. But if the past 40 years of research have taught me anything, it is never to underestimate this little molecule. The age of RNA is just getting started.

Thomas Cech is a biochemist at the University of Colorado, Boulder; a recipient of the Nobel Prize in Chemistry in 1989 for his work with RNA; and the author of “The Catalyst: RNA and the Quest to Unlock Life’s Deepest Secrets,” from which this essay is adapted.

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The joy of birdwatching: Research shows it can improve mental health and foster a sense of wellbeing

The mental health benefits of being in nature have long been acknowledged, whether through activities like listening to birdsong or taking a walk in the park.

While birdwatchers are often portrayed as boring , it turns out that twitchers have been onto something all along. A study published in 2024 shows that even half an hour of bird watching could make us happier, healthier and help foster a deeper connection with nature.

We already know that listening to birds throughout the day positively impacts our wellbeing. Even hearing birds indoors, through an open window can boost our emotional state, albeit in the short-term.

The study suggests that not only can birdwatching offer even more benefits than just listening to birdsong, it’s more effective at increasing wellbeing and reducing stress than going on a nature walk.

So, why is birdwatching so good for us?

Biophilia could be a big part of it. Biophilia is the belief that humans have an affinity with nature – some would argue that we should see ourselves as part of nature – so being in natural surroundings makes us feel well. But biodiversity could play a role too.

‍ Research suggests that biodiversity is a natural medicine for humans that can help reduce stress and encourage physical activity.

My research, though, focuses on positive psychology and nature. I explore which resources are fundamental to improving wellbeing and help people go beyond feeling “good enough” mentally to flourishing – the highest level of wellbeing. My research, then, could help explain why birdwatching is so beneficial for mental health.

Twitching with happiness

Birdwatching can boost positive emotions – the foundation of wellbeing. Research shows that conscious experiences of emotions affect wellbeing more positively. For example, a study asked participants to either count how many birds they had seen, or rate their joy upon seeing each bird species – both groups reported wellbeing boosts.

However, the joyful group experienced the most remarkable improvement, suggesting that participants’ awareness of positive emotions while birdwatching may have boosted the activity’s benefits.

But birding can be awesome as well as joyful. Research suggests that experiencing awe of nature can be transformational for human wellbeing. “ Noticing ” is an essential aspect of awe. Noticing means that our full attention is on the birds rather than ourselves. Being in nature and noticing wildlife, then, requires us to immerse ourselves in the activity, which can improve mental and physical health .

The birds and the bees

Unlike the “boring birder” stereotype so popular in TV and film, birdwatching is not a dull, passive activity. It is an engaging pursuit that captivates the mind. Recently, my colleague and I conducted research on the impact of bees on the mental health of beekeepers and their families.

We found parallels between beekeepers and birdwatchers: both experienced a deep engagement and profound sense of tranquillity through hours of observing their subject.

Like birdwatchers, beekeepers can become so absorbed in their observations that they lose track of time and surroundings, enveloped entirely in the hive’s dynamics. This immersion triggers a psychological flow crucial for overall mental wellbeing.

Psychological flow is a state of deep absorption in an activity. It’s characterised by intense concentration, a seamless sense of involvement and a feeling of mastery. This mental state is not only a sign of enhanced performance, but also a key to overall wellbeing. It’s often compared to being “in the zone”, a state where we feel our best and perform at our peak.

One of the reasons that birdwatching is so good for us is that it can produce this experience of psychological flow. Twitchers become fully engrossed in identifying bird species, deciphering their behaviours, and observing their actions. This flow state emerges organically, fuelled by curiosity, heightened concentration and sustained engagement. After being “in the flow” birdwatchers can experience a rush of endorphins and a profound sense of satisfaction and wellbeing.

Our study found a strong bond between beekeepers and their bees, similar to “ positivity resonance ” – a deep emotional and physiological connection with another living entity, often resulting in feelings of joy and satisfaction.

This resonance, we found, significantly bolsters beekeepers’ happiness and overall wellbeing, fostering a profound sense of harmony in the beekeeper and a sense of unity with the bees. Observing birds could promote a similar experience for birdwatchers.

Recent research on the beekeepers and birdwatchers, then, confirms the power of nature-centred therapies for improving mental health. So, grab your binoculars and step into nature for a twitching session and a wellbeing boost. Embrace the journey and savour every moment.

This article was written by Jolanta Burke from the RCSI University of Medicine and Health Sciences and was originally published on The Conversation .

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U of G Arboretum Awarded For Conserving Ontario’s Natural History 

A beloved community and research landmark, the University of Guelph’s Arboretum is the 2024 recipient of Ontario Nature ‘s Natural History Award .  

The award honours individuals and groups that have made a significant impact toward protecting nature in Ontario and promoting conservation biology. 

The Arboretum has been an internationally renowned site of this work for more than 50 years, offering free admission and extensive community programming, with a mission to serve as an outdoor learning resource for campus and the community. 

Arboretum Director Justine Richardson accepted the honour at the Ontario Nature’s Conservation Awards on June 1 at the Evergreen Resort in the Saugeen Bruce Peninsula. 

“The Arboretum has grown in 50 years to become an essential green space,” says Richardson. “As we look at the urgencies of climate change, biodiversity loss, our obligation to Indigenous communities and the mental and physical well-being and connection to nature for our people, I believe the Arboretum has a role to play in today’s major issues.”  

The Arboretum was nominated by Nature Guelph , a local charity focused on environmental education and community conservation initiatives.  

“There are many organizations in Ontario with broadly similar goals of engaging the public with nature, but the Arboretum stands out for the variety, depth and reach of its activities,” the organization said in its nomination. 

‘Generations of decision-makers’ support Arboretum’s conservation efforts  

The Edna and Frank C. Miller English Garden

Historically rooted in the 1880s, when the Ontario Agricultural College began its studies on woody plants, the Arboretum was officially established in 1970 as a “living laboratory” for research, education, outreach and conserving biodiversity for future generations.  

Today, it encompasses 400 acres rich in biodiversity and is one of the most visited parts of campus, with 100,000 annual visitors enjoying its plant collections ,  walking trails , gardens , natural woodlands, wetlands and meadows . The forested areas include some of the oldest and most unique heritage forests in the city of Guelph. 

Since the late 1970s, Arboretum staff have worked with landowners to document the status of rare woody plant species in Ontario to advise on preservation. Today, more than 30 species of threatened or endangered woody plants are archived in the Arboretum’s grounds and gene banks. These gene banks take pressure off wild populations and support the plants’ ability to naturally regenerate.  

For instance, the Elm Recovery Project , which began at the Arboretum in 1998, has had a significant impact by identifying and testing a biodiverse set of American elm trees for tolerance to Dutch Elm disease.  Now entering its second generation of tested elms, the project represents the long-term commitment that tree research requires and aims to reintroduce biodiverse populations of disease-tolerant trees to the Ontario landscape. 

The Arboretum’s most recent addition to its gene banks is red mulberry trees . As only 200 to 300 red mulberry understory trees are left in the province, the Arboretum is working with landowners and organizational partners to test and propagate them. This will establish a long-term seed orchard and contribute to species recovery.   

Similarly, the Arboretum’s seed collection program protects rare and threatened seeds and plants and is used in international conservation efforts. The overall collection now numbers over 1,700 taxa of woody plants. 

Arboretum inspires community to preserve natural environments 

The Arboretum’s demonstration gardens , including the Japanese, English and Italian Gardens, showcase artistic and cultural diversity while informing visitors of different plantings that provide food, cover and shelter for wildlife. 

Richardson adds the Arboretum is a critical location to support the mental health of students during stressful times during the semester and also serves as a site of experiential learning.  

A number of citizen science projects track and observe wildlife species. This contributes to scientific research data and also connects students with the community in educational training programs. 

Other initiatives include the Arboretum’s annual “ Arb Expo & Plant Sale ,” which brings the community together to showcase horticulture and nature to over a thousand visitors. For over 30 years, this has provided native, locally sourced plants to the public, and offers a family-friendly forum to make connections, tour the university facilities and take home a plant for one’s own garden. 

“Generations of decision-makers have supported the space,” says Richardson. “My hope is that the Arboretum continues to grow and to provide a healthy space for the trees and wildlife and the people who access it.” 

She adds: “Thank you to Ontario Nature, Nature Guelph and to the many people who have made and still make this place so special, including our passionate staff who are so knowledgeable, our dedicated volunteers, donors and community supporters, as well as the faculty, staff and students who use the Arboretum for teaching and research every day.” 

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Nature journaling encourages people to slow down and look at the world in curiosity, wonder

Nature journaling is a practice that has been around for centuries.

While the movement has taken off in the United States, a new organisation in Australia hopes more people will head outside with a pencil case and notebook and record what they see.

The Australian Association of Nature Journaling is holding its inaugural conference at the Queensland Museum this week.

Founding president Julia Landford said nature journaling encouraged people to see the world around them differently.

"Here in Australia, it's a relatively new practice," Ms Landford said.

"Nature journaling is a wonderful way to look more closely at nature.

"That includes actually stopping and taking the time to see what's going on around us.

"It might be looking at a flowering plant and following its progress over a number of seasons to see how the flowers become seeds and how that whole life cycle occurs for that plant."

How to get started

To get started with nature journaling, Ms Landford says all you need is a small pencil case and a visual art diary.

She said a lack of art skills or access to wilderness was not a barrier.

"You can be doing it in your own backyard or on your back verandah and some pot plants," she said.

"Just start drawing what you see and have a really close look at what you're looking at.

"You don't have to be a perfect artist to be able to do this. It's for you, your interests and building those memories of the places you're visiting."

Ms Landford said it was not limited to drawing or painting.

"Nature journaling is also about thinking and operating as a scientist and as a citizen scientist and starting to ask questions about ecology and about the environments that we see around us," she said.

"Be curious, pay attention, notice things differently, have that sense of wonder about what's going on around us, spend more time outdoors and use all of your senses."

Just 'have a go'

Tasmanian artist and nature journaler Keith Davis said he has journaled on and off all his life.

"More recently during [the] COVID [pandemic] I got to sharing some nature journaling stuff on social media platforms and that generated some interest," he said.

He said he hoped sharing his journals might encourage more people to reconnect with nature.

"Anyone can start a journaling practice, there's no hard and fast rules. You can do it your own way, you can personalise it," he said.

"I often hear people say, 'I can't draw so I couldn't do it', but you don't have to be an artist.

"The more you practice, the more you improve."

He recommended to get started by spending time in nature and slowing down.

"It doesn't matter if your sketches are a bit rough."

Mr Davis captures basic information about where he is, the season and weather conditions.

"I find it very peaceful and relaxing, I really enjoy it, even if I only do it for a short time," he said.

The benefits

Ms Landford teaches nature journaling through her Canberra-based arts and environmental education organisation.

She set up the national association about a year ago after a trip to the United States to visit John Muir Laws who created a movement around nature journaling.

She said she wanted people across Australia to be able to connect and share their work and ideas.

Ms Landford said because nature journaling involves eye, hand and brain connections to record memories, they become embedded in a much different way than just taking a photo.

"If you take a photo with your mobile phone, you're just pressing a button. But if you're doing a drawing, it actually changes the way our brains and our memory process that experience.

"And it embeds those experiences as memories and those memories then help us to access and understand much better what it is that we're seeing and where we were back at that time."

She said nature helps reduce high blood pressure, heart disease and stress and anxiety.

"There's an enormous amount of research that demonstrates the benefits of exposure to the natural world, as well as the benefits of just slowing down and taking time out from our busy lives," she said.

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