We’ve all taken a walk in the park to clear our minds and refresh our spirits. However, scientific studies show that time spent in green spaces can actually renew attention, reduce aggression, improve self-control, and even help to ease symptoms of ADHD. This is especially important as major cities such as San Diego, Washington D.C., Chicago, and Philadelphia lose their tree cover.

As early as the mid-1800s, city planners recognized the importance of green spaces. When his plan for New York City’s Central Park was put into place in 1865, Frederick Law Olmsted said, “It is a scientific fact that the occasional contemplation of natural scenes . . . is favorable to the health and vigor of men.” Over the next century, scientists developed theories and offered mounting evidence to prove that statement true.

In the 1980s, Stephen Kaplan, a psychology professor at the University of Michigan, developed the attention restoration theory (ART). In simple terms, this theory suggests that natural stimuli (trees, grass, stars, etc.) engage our involuntary attention, requiring little effort and energy to engage in the environment. Conversely, urban stimuli (cars, lights, billboards, etc.) demand voluntary attention. Voluntary attention requires considerable focus and energy and is therefore susceptible to attentional fatigue. Thus, exposure to the natural environment actually rejuvenates attentional capacities, because it gives voluntary attention a rest.

Kaplan published his theory in 1995.1 In the following years, a number of published studies supported and expanded upon ART. Scientists at the Landscape and Human Health Lab at University of Illinois, Urbana-Champaign were particularly prolific, producing findings such as:

• Fatigued attention—caused by lack of exposure to natural greenery—can result in increased aggression.2
• Decreased exposure to nature results in decreased self-control.3

These same scientists then hypothesized that attentional fatigue may exacerbate attention deficit symptoms and that natural landscapes could help to alleviate these symptoms. Several studies supported this hypothesis, including:

• “Coping with ADD: The Surprising Connection to Green Play Settings” (Taylor, Kuo, & Sullivan, 2001)4
• “A Potential Natural Treatment for Attention-Deficit/Hyperactivity Disorder: Evidence from a National Study” (Kuo & Taylor, 2004)5
• “Children with Attention Deficits Concentrate Better after Walk in the Park” (Kuo & Taylor, 2008)6

Whether using parental observations and ratings or a digit span task, the studies all demonstrated that time spent in green spaces makes children with ADHD calmer, more responsive, and better able to concentrate. Even despite criticisms of some of the study designs7, the consensus remains that people who are exposed to the natural environment function better than people who are not. Therefore, we may be wise to more closely guard our diminishing urban parks and forests, or our mental health may suffer the consequences.

Resources from Wiley on This Topic
	Handbook of Environmental Psychology by Robert B. Bechtel and Arza Churchman
	Conservation Psychology: Understanding and promoting human care for nature by Susan Clayton and Gene Myers

1. KAPLAN, S. (1995). The restorative benefits of nature: Toward an integrative framework Journal of Environmental Psychology, 15 (3), 169-182 DOI: 10.1016/0272-4944(95)90001-2
2. Kuo, F., & Sullivan, W. (2001). Aggression and Violence in the Inner City: Effects of Environment via Mental Fatigue Environment and Behavior, 33 (4), 543-571 DOI: 10.1177/00139160121973124
3. TAYLOR, A. (2002). VIEWS OF NATURE AND SELF-DISCIPLINE: EVIDENCE FROM INNER CITY CHILDREN Journal of Environmental Psychology, 22 (1-2), 49-63 DOI: 10.1006/jevp.2001.0241
4. Taylor, A., Kuo, F., & Sullivan, W. (2001). Coping with add: The Surprising Connection to Green Play Settings Environment and Behavior, 33 (1), 54-77 DOI: 10.1177/00139160121972864
5. Kuo FE, & Taylor AF (2004). A potential natural treatment for attention-deficit/hyperactivity disorder: evidence from a national study. American journal of public health, 94 (9), 1580-6 PMID: 15333318
6. Faber Taylor, A., & Kuo, F. (2009). Children With Attention Deficits Concentrate Better After Walk in the Park Journal of Attention Disorders, 12 (5), 402-409 DOI: 10.1177/1087054708323000
7. Canu, W., & Gordon, M. (2005). MOTHER NATURE AS TREATMENT FOR ADHD: OVERSTATING THE BENEFITS OF GREEN American Journal of Public Health, 95 (3), 371-371 DOI: 10.2105/AJPH.2004.055962