| Some associated theories and theorists | • Stress reduction theory (Ulrich, 1983) • Attention restoration theory (Kaplan and Kaplan, 1989) • “Old friends” hypothesis (Rook, 2013) • Forest medicine (Li, 2010) • Perceptual fluency account (Joye and van den Berg, 2011) | • Ecological psychology (Gibson, 1986; Reed, 1996a,b; Chawla, 2021) • Capabilities approach to human development (Sen, 1985; Nussbaum, 2011) • Self-determination theory (Deci and Ryan, 1985) • Theory of loose parts (Nicholson, 1971) |
| Some associated benefits | • Decreased physiological levels of stress • Increased positive emotions • Reduced anxiety, depression, and negative moods • Better working memory • More focused attention • Improved immune system activity • Lower rates of many diseases | • Autonomy • Sense of competence and efficacy • Physical balance, agility and coordination • Sense of vitality • Creativity • Engaged learning • Cooperative social relationships • Relatedness with other species and living things • Peaceful refuge |
| Some suggested mechanisms | • Stress hormones decrease in safe natural areas • When extended focused attention leads to mental fatigue, views of nature and being in nature restore depleted cognitive resources through fascination, compatibility, a sense of extent, and being away from sources of stress • Microbiomes associated with biodiverse environments stimulate immune system development • Volatile oils from trees increase Natural Killer cells and other markers of protective lymphocyte activity • The human visual system fluently processes the structure of green settings, in part due to fractal patterns in nature | • Many elements of nature, animate and inanimate, immediately respond to engagement—providing information for feelings of effectance and intrinsic motivation to continue learning about properties of the natural world and capacities of the self • The natural world's sensory diversity, manipulability, and inherent change encourage interest and curiosity • Natural settings afford free movement and free choice in selecting activities as well as setting and mastering challenges • Because nature's elements were not manufactured by humans for prescribed purposes, they invite creative use • The number and variety of “loose parts” in nature invite creative combinations • Natural areas provide refuges to escape over-stimulation, relax, and sort out thoughts and feelings • Natural settings provide materials for imaginative play and construction that require social cooperation • In some cultures, traditional interactions with regional landscapes are an important part of cultural identity |
| Typically recommended interventions | Planners, designers, developers, park managers, school administrators, teachers, and other professionals provide nearby nature: • Views of trees outside buildings • Trees along streets and pedestrian pathways • Landscaping for nature around homes and neighborhoods • Naturalizing the grounds of schools and child care centers • Bringing nature into buildings and classrooms through green walls and plants | In addition to providing access to nature, family members, teachers, staff in environmental organizations, other community mentors, and designers facilitate: • Free play and exploration in nature • Manageable risk-taking outdoors • Appreciative and caring attention to nature • Skills for outdoor recreation and the sustainable use of nature • Collective work to protect and restore the natural world • Learning across the curriculum in outdoor classrooms, using elements of nature • Place-based education that focuses on learning local natural and cultural history • Participatory processes that engage people who use environments, including children, in planning, designing, and creating green spaces |