Perspective

Living in cities, naturally

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Science  20 May 2016:
Vol. 352, Issue 6288, pp. 938-940
DOI: 10.1126/science.aaf3759

Abstract

Natural features, settings, and processes in urban areas can help to reduce stress associated with urban life. In this and other ways, public health benefits from, street trees, green roofs, community gardens, parks and open spaces, and extensive connective pathways for walking and biking. Such urban design provisions can also yield ecological benefits, not only directly but also through the role they play in shaping attitudes toward the environment and environmental protection. Knowledge of the psychological benefits of nature experience supports efforts to better integrate nature into the architecture, infrastructure, and public spaces of urban areas.

Crowding, noise, and other stressful urban conditions increase the risk of mental disorders such as anxiety and depression (1). However, urban areas also have environmental assets that support mental health. For example, parks, green spaces, street trees, and community gardens can facilitate physical activity, social contacts, and stress reduction (1, 2). How can psychological benefits from encounters with natural features and processes offset the psychological costs of other urban living conditions? Answers to this question will help improve the quality of life of today’s growing urban populations (2, 3) (Fig. 1).


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Fig. 1

Together with ecological benefits such as climate change mitigation and the protection of biological diversity, the renaturing of cities opens opportunities for people to engage with features and processes of the natural world; for example, when tending plants in a community garden.

PHOTO: © BOHEMIAN NOMAD PICTUREMAKERS/CORBIS

In his classic work on urban psychology, Stanley Milgram opened on a positive note, arguing that “cities have great appeal because of their variety, eventfulness, possibility of choice, and the stimulation of an intense atmosphere that many individuals find a desirable background to their lives” (4). He also saw that cities offer “unparalleled possibilities” for face-to-face contact and communication (4). Yet, when considering how psychology can contribute to understanding the experience of living in a city, he turned to the negative; he highlighted overload as a psychological concept useful for linking objective urban circumstances such as high population density to observable behaviors such as incivility. Such contrasting perspectives continue to inform psychological research on urban life.

Urban-rural differences in mental disorders

Numerous studies have suggested that urban living conditions undermine mental health, whereas conditions in rural areas support health. Peen et al. (5) performed a meta-analysis of 21 studies, done after 1985, that investigated the prevalence of mood disorders among non-institutionalized adults in relatively affluent countries. They found that the odds of mood disorder were 28% higher in the urban areas than in the rural areas; however, the results were highly heterogeneous, perhaps because “rural” and “urban” were defined differently in different studies. They recognized the problem with integrating results when urban settings in some studies resemble rural settings in others.

Judd et al. (6) have argued that binary urban and rural categories are insufficient. Numerous environmental factors can affect the stress that people experience in urban and rural settings and, thus, the prevalence of disorders such as anxiety and depression. These include, for example, residential density, housing quality, air quality, transportation options, access to health and welfare services, and access to parks and green spaces. All of these factors might play a role in whether a given individual develops a disorder, but they may do so in different ways in different combinations. Together with individual vulnerabilities and broader contextual characteristics, research must consider the independent and combined effects of these factors in order to elucidate how specific urban conditions may undermine or support mental health.

Findings of urban-rural differences in mental disorders might be taken as warnings about the consequences of urbanization, but there is a risk of confusing cause and effect. The social, political, and economic forces that drive urbanization in a particular society may also generate mental illness through other mechanisms. For example, in some countries, many people have left rural areas for urban ones under threat of violence; this appears to have boosted the prevalence of major depressive disorder (7). Poor conditions in the spontaneous settlements they create may exacerbate the effects of victimization, disruption of social relations, and loss of traditional occupations, but urbanization itself is not the initial cause of disorder.

Psychological benefits of nature experience

Research on the experience of nature also suggests that urban living conditions can undermine mental health, whereas relatively natural conditions can support it. The term “nature” means different things in different contexts. Recognizing personal and cultural aspects of the experience of nature, psychological research considers how different people encounter nature in diverse contexts, from viewing indoor plants in urban offices to walking in wilderness areas.

A significant portion of this research concerns the restorative effects of nature experience, such as regaining the ability to concentrate and reducing blood pressure after intensive mental work (3, 8). Theories about restoration describe how encounters with nature involve psychological distance from everyday demands and interested engagement with environmental features and processes. These components of restorative experience have counterparts in many analyses of why people engage in outdoor recreation, done in the United States and elsewhere since the early 1960s (8). Complementing what people have long said they seek through outdoor recreation and substantiating theoretical claims, laboratory and field experiments have repeatedly shown that spending time in natural environments or viewing scenes of nature can quickly help people to lift their mood, improve their ability to direct attention, and reduce physiological arousal to a greater degree than do urban streets and other comparison conditions (2, 8).

As in studies of urban-rural differences in mental disorders, comparisons of single examples of urban and natural environments have been criticized for neglecting relevant forms of variation (8). Experimental evidence regarding plausible mechanisms has nonetheless encouraged large observational studies on urban green space and health. Such studies consider plausible cumulative effects of green space and greenery near an urban home. Most such studies focus on quantity, but some have also used quality indicators (9). Most of the observational studies have used a cross-sectional design, but recent longitudinal studies have enabled stronger inferences regarding beneficial effects of access or proximity to nature. For example, using 5 consecutive years of data for each of 1064 participants in the British Household Panel Survey, Alcock et al. (10) showed that those who relocated from a less green (58% local area coverage) to a more green (74%) urban area showed improved mental health over the next 3 years. In contrast, those who moved from more (74%) to less (59%) green urban areas showed a decline in mental health before the move, followed by a return to the pre-move baseline.

Much research on nature experience assumes that too few generations have passed for natural selection to shift the adaptedness of affective and cognitive functioning from the conditions of hominid evolution (8), and that humans are therefore poorly adapted to living in urban environments, broadly defined. This natural-urban antithesis neglects the fact that urban environments include settings that are supportive of human functioning; noisy, polluted, car-filled streets lined by anonymous towers are not representative of all urban possibilities. This false antithesis also neglects reasons why people gathered in cities millennia ago, and the consequences of that move for the interplay of natural selection and sociocultural development. Here too, the environmental categories and the urbanization process need closer examination.

The design of cities and human-nature relations

Psychological research has substantiated long-standing reasoning about parks and green spaces as health resources for urban populations (8, 11, 12). This reasoning has guided the creation of parks in many cities, such as Central Park in New York and Mount Royal Park in Montreal. Extending such precedents, researchers, design professionals, citizen groups, and others are working together to create sustainable urban fabrics in our increasingly urbanized world. These efforts—under banners such as green urbanism, green infrastructure, biophilic design, and renaturing—seek a better synthesis of natural processes and ecosystem functions with architecture and urban infrastructure through acts of creation, preservation, and ecological restoration. Such efforts are needed for psychological as well as ecological purposes. The evidence mentioned above and more like it warn against assuming that people can simply adapt to increasing urban density and its concomitants without negative consequences for health and well-being.

By providing opportunities for people to experience nature in cities and to experience cities as natural, such efforts can shape attitudes toward the environment (Fig. 2). People in increasingly large and dense urban areas may have few or no contacts with the natural world in everyday life. Environmental generational amnesia refers to the psychological process whereby each generation constructs a conception of what is environmentally normal based on the natural world encountered in childhood (13). A problem arises insofar as the amount of environmental degradation increases across generations, but each generation tends to take that degraded condition as the nondegraded condition: the normal experience. This helps to explain inaction on environmental problems; people do not feel the urgency or magnitude of problems because the experiential baseline has shifted. Providing opportunities for people to experience more robust, healthy, and even wilder forms of nature in cities offers an important solution to this collective loss of memory and can counter the shifting baseline (14). Such opportunities include, for example, large green spaces and parks, rivers restored to some former free-flowing condition, expansive views over water and land, and extensive connective pathways for walking and biking.


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Fig. 2

People living in cities can encounter nature in the context of many different activities. Their experiences can enhance their development, health, and well-being, and they can shape their attitudes toward the environment and environmental protection.

PHOTO: © MONALYN GRACIA/CORBIS

Thus, cities designed well, with nature in mind and at hand, can be understood as natural, supportive of both ecosystem integrity and public health. Further psychological studies can describe how specific improvements in available opportunities for nature experience come to affect mental health and environmental attitudes (15). How will they change if car-clogged spaces give way to natural places where children can play wildly and others reflect quietly?

References

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