1. Introduction
Throughout history, humans have had an intimate relationship with nature, most obviously depending on it for subsistence and production. As modern society emerged, and the human population condensed into urban areas, industrialisation freed many people from reliance on direct consumptive interactions with nature. Indeed, in post-war society, people-nature interactions have fundamentally shifted from direct consumption and exploitation to more mutualistic relationships in which people actively seek out interactions with nature for recreation and enjoyment [
1,
2]. Interacting with nature may therefore be important not only for survival, but also for human quality of life [
3,
4,
5]. Indeed, there is mounting empirical evidence that interacting with nature delivers a range of measurable human benefits [
6,
7,
8], including positive effects on physical health [
9,
10,
11], psychological well-being [
12,
13,
14], cognitive ability [
15] and social cohesion [
16]. Reviews on this topic have been published in the past, but these have generally focused on a specific type of benefit, e.g., [
17], have been limited to a single discipline, e.g., [
18,
19,
20], or have covered the benefits arising from a particular type of interaction, e.g., [
21,
22,
23].
Understanding the benefits of interacting with nature is important for maintaining and improving human well-being in a rapidly urbanising world. For example, evidence that living in close proximity to green spaces delivers health benefits [
24] could be used to design landscapes with broader societal benefits such as reductions in health spending [
18] or crime rates [
25]. However, without a clear view of the quality of evidence, and information on any potential thematic or geographic bias in the available information, it is difficult to come to clear conclusions about which particular features of the environment, including their ecological characteristics, might deliver these benefits.
Our review focuses on three critical questions. First, we explore the geographic distribution of studies into the benefits of interacting with nature. This is an important issue, not least because the amount and type of nature that can be experienced varies enormously across the World. For example, the tropics are much more biodiverse than higher latitudes [
26] and the extent to which natural landscapes have been cleared for human use also shows a strong spatial pattern [
27]. Important changes in the type of biodiversity present accompany the increase in biodiversity toward the tropics. For example, bites from venomous snakes show a very strong bias toward equatorial regions [
28], and zoonotic diseases are similarly geographically biased [
29], suggesting that some of the more important negative aspects of interacting with nature might be overlooked if the research is biased toward high latitudes. Bias in the location of studies could also lead to skewed representation of different human cultures [
30,
31].
Second, we examine the types of benefits studied to understand whether some have received more focus than others. For example, the growing availability of databases of health status or interventions and detailed land maps has facilitated correlational investigation of access to green space with health outcomes such as morbidity, e.g., [
10,
24]. In contrast, less tangible benefits such as spiritual well-being or social cohesion may be more challenging to study.
Third, we review in some detail the basis for the evidence surrounding each of the identified benefits of people-nature interactions. For a benefit to happen, a setting in which nature can be experienced must exist, and an interaction between humans and nature must occur. However, we are aware of no published typologies of these settings, and few that detail the interactions [
7,
23,
32] or benefits [
7,
33], which hinders a synthesis of the research into the benefits of experiencing nature. Before going on to address the three questions outlined above, we first build typologies of: (i) the settings in which people-nature interactions can occur, (ii) the types of interactions that occur between people and nature, and (iii) the benefits that can arise from these interactions.
4. Conclusions
Our review has identified a typology of three categories of nature-interaction—indirect, incidental and intentional—as well as six key types of benefits that may be experienced from a variety of natural settings. All of the reviewed studies were undertaken in developed countries, mostly Western societies, and there is a clear bias in the literature with respect to cultural and socio-economic differences between geographic regions. It is thus difficult to determine which of the reported benefits of interacting with nature are universal, and which are culturally specific. While it has been hypothesized that humans have an instinctive connection with nature [
3], this connection may manifest itself differently in different cultures owing to different value systems and attachments to natural areas. A mix of theoretical and empirical work may well be needed to further examine this important dimension of the benefits of interaction with nature.
The body of literature is broad and spans several disciplines although the majority has been conducted from within the social sciences. The noticeable lack of contribution from the environmental and biological sciences has meant that we know little about which specific ecological features of the environment might be important for delivering a beneficial response. The sophisticated tools available within ecology for measuring characteristics of the biological component of landscapes, such as species richness, vegetation structure and community composition, could provide fruitful insight into this issue. For example, what type of vegetation structure is needed, and how many species should be planted to maximise the well-being value of an urban green space? To remedy this, we encourage further engagement by ecologists to investigate the extent to which the biological richness of a landscape, as opposed to an often loosely defined “nature”, plays an important role in enhancing beneficial interactions.
Overall, there is good evidence to suggest that natural settings can have multiple beneficial effects. It was clear from the reviewed studies that some types of benefits have been much more heavily studied than others; psychological, cognitive and physiological benefits featured most prominently with fewer studies of social, spiritual and tangible benefits. Given the possible wider societal benefits from increased social cohesion [
4] or the role that spiritual well-being might play in influencing the way people value nature [
94], the latter benefits deserve considered attention in future research.
When drawing conclusions from the existing literature, this review suggests caution is appropriate. There were several general methodological limitations that recurred throughout the body of reviewed literature. Firstly, much of the evidence has been derived from self-report questionnaires, particularly in the studies focused on psychological and social benefits. Secondly, sampling bias may have influenced results in some cases, especially for studies that recruited participants in situ. Thirdly, the reviewed studies were generally conducted over relatively short time frames leaving our understanding of the long-term benefits of interacting with nature unstudied. Lastly, many experimental studies did not include an appropriate control group therefore confounding variables such as age, gender and personal values may have influenced the results.
The summative insight across these studies provides important indication of the potential range of benefits yet there remains the possibility that some or many of the widely accepted benefits of interacting with nature are actually not causally related to nature itself. For example, while the psychological benefits associated with exercising in natural areas have received considerable focus, there is limited evidence to suggest that these interactions have positive psychological and physiological effects. It is clear, though, that whilst exercising in natural environments may not deliver psychological and physiological benefits, natural areas may be important for facilitating exercise, particularly in urban areas. Similarly, there is strong evidence to suggest that natural settings, such as community gardens, can be important for facilitating social contact, though it is unclear whether collaborative activities in these natural settings can actually increase social capital in the wider community.
Interactions with nature can positively influence behaviour, academic performance and social skills in children [
62,
69], something that could be reflected in school curricula (e.g., environmental experience components) and could have broader benefits, such as reducing bullying in schools. Much of the evidence is based on self-reported perceptions of parents and guardians, and the majority of these studies have been undertaken over relatively short timeframes. For example, while childhood interactions with nature may influence attitudes towards the environment in later life [
79], which could have positive implications for future conservation efforts, longitudinal studies will be necessary to more fully evaluate the development of environmental values and behaviours from childhood.
Understanding the benefits of interacting with nature is also important from a sustainability perspective. Unsustainable exploitation of natural resources has resulted in the loss and degradation of species and ecosystems worldwide [
102]. The natural systems that have sustained human livelihoods throughout history have been severely impacted, consequently human quality of life has been inadvertently threatened. The solutions to the current biodiversity crisis are complex and will depend on broad-scale conservation efforts, effective landscape management and innovative urban planning. Strong public support will be necessary to encourage governments to implement effective conservation policies [
102], and positive interactions with nature might be important for influencing an individual’s sympathy for conservation goals [
83]. However, opportunities for these interactions are being reduced as urbanisation increases and the majority of the human population now resides in urban areas [
83,
103]. Therefore, protecting and enhancing biodiversity in these urban areas could be critical for achieving conservation objectives and maintaining human quality of life during this period of major global change.
Overall, this literature review has documented a broad range of the benefits of interacting with nature. It has been shown that interactions with nature can deliver a range of psychological well-being, cognitive, physiological, social, tangible and spiritual benefits and that access to green space and natural areas is important for facilitating activities that are beneficial for human well-being. However, because the evidence is mostly descriptive, little is known about the mechanisms that are important for delivering these benefits and so key questions still remain. What characteristics of natural settings (e.g., biodiversity, level of disturbance, proximity, accessibility) are important for triggering a beneficial interaction? How do these characteristics vary in importance between different cultures, geographic regions and socio-economic groups? These are important directions for future research if we are to make effective, informed decisions regarding the best ways to maximise opportunities for people to interact with nature in a rapidly urbanising world.