Vegetation and Violence

A study conducted by Frances E. Kuo Natural Resources & Environmental Sciences University of Illinois at Urbana-Champaign

With funding from The Cooperative State Research, Education and Extension Service, U.S. Department of Agriculture The Cooperative State Research, Education and Extension Service, U.S. Department of Agriculture The USDA Forest Service The USDA Forest Service Urban and Community Forestry Program on the recommendation of the National Urban and Community Forestry Advisory Council The University of Illinois at Urbana-Champaign The University of Illinois at Urbana-Champaign

Take home message

Where there is less nature nearby, there is more aggression and violence. Take home message

Why Study Vegetation and Violence? Why Study Vegetation and Violence? The Approach The Approach The Findings The Findings So What? So What? Presentation outline

Why Study Vegetation and Violence?

In the inner city, violence levels are high, and vegetation is scarce.

Could there be a connection between scarce vegetation and high rates of violence?

Near- home nature Less mental fatigue Green surroundings may reduce mental fatigue…

And less mental fatigue may be linked to less aggression. Less aggression and violence Less mental fatigue

Mental fatigue may lead to aggression by impairing the ability to handle problems rationallyimpairing the ability to handle problems rationally

Mental fatigue may lead to aggression by impairing the ability to handle problems rationallyimpairing the ability to handle problems rationally causing inattentivenesscausing inattentiveness

Mental fatigue may lead to aggression by impairing the ability to handle problems rationallyimpairing the ability to handle problems rationally causing inattentivenesscausing inattentiveness increasing irritabilityincreasing irritability

Mental fatigue may lead to aggression by impairing the ability to handle problems rationallyimpairing the ability to handle problems rationally causing inattentivenesscausing inattentiveness increasing irritabilityincreasing irritability decreasing control over impulsive behaviordecreasing control over impulsive behavior

The demands of poverty may place inner city residents at high risk for mental fatigue and the aggression it fosters.

Adding nature to the inner city may reduce these risks. Near- home nature Less aggression and violence

1 2 3 This study examines the following relationships: Near- home nature Less aggression and violence Less mental fatigue

The Approach

The Robert Taylor Homes were chosen as a research site because buildings are similar; only the quantity of nearby vegetation differsbuildings are similar; only the quantity of nearby vegetation differs

The Robert Taylor Homes were chosen as a research site because buildings are similar; only the quantity of nearby vegetation differsbuildings are similar; only the quantity of nearby vegetation differs residents are randomly assigned to buildingsresidents are randomly assigned to buildings

The Robert Taylor Homes were chosen as a research site because buildings are similar; only the quantity of nearby vegetation differsbuildings are similar; only the quantity of nearby vegetation differs residents are randomly assigned to buildingsresidents are randomly assigned to buildings residents have similar characteristicsresidents have similar characteristics

The participants were 145 female, heads of household, under 65 years old145 female, heads of household, under 65 years old

The participants were 145 female, heads of household, under 65 years old145 female, heads of household, under 65 years old from 18 buildings that varied along the full range of amount of nearby naturefrom 18 buildings that varied along the full range of amount of nearby nature

The participants were 145 female, heads of household, under 65 years old145 female, heads of household, under 65 years old from 18 buildings that varied along the full range of amount of nearby naturefrom 18 buildings that varied along the full range of amount of nearby nature recruited by interviewers going door-to-doorrecruited by interviewers going door-to-door

Method The 18 buildings were categorized as being either high or low in nearby nature.The 18 buildings were categorized as being either high or low in nearby nature.

Robert Taylor Homes without trees (barren) Robert Taylor Homes with trees (green)

The 18 buildings were categorized as being either high or low in nearby nature.The 18 buildings were categorized as being either high or low in nearby nature. Residents mental fatigue was measured.Residents mental fatigue was measured. Method

The 18 buildings were categorized as being either high or low in nearby nature.The 18 buildings were categorized as being either high or low in nearby nature. Residents mental fatigue was measured.Residents mental fatigue was measured. Residents levels of aggressive and violent behavior were measured.Residents levels of aggressive and violent behavior were measured. Method

Near- home nature Less aggression and violence Less mental fatigue

The relationships between all three measures were then analyzed. Amount of vegetation outside home Scores on test of attention Aggressive tactics used against partner

The Findings

This study found a clear link between green surroundings and reduced mental fatigue. Near- home nature Less mental fatigue

More nature near home, less mental fatigue Mean number correct on attention measure Greenness rating of residence 5 4 greenbarren 4.5 More correct = less fatigued attention

And residents with less mental fatigue reported less aggression and violence. Less aggression and violence Less mental fatigue

Finally, there was a clear link between having near-home vegetation and less aggression and violence. Less aggression and violence Near- home nature

Nearby nature leads to less violence and aggression More aggression Less aggression

Nearby nature leads to a smaller range of violence and aggression More types of aggression Fewer types of aggression

In sum,

In sum, individuals living in green surroundings were less mentally fatigued,

In sum, individuals living in green surroundings were less mentally fatigued, and less aggressive and violent.

So What?

Because violence begets violence, reducing violence now is likely to reduce violence in future generations.

Suggestions for individuals If angry, take a walk in green surroundings.

Spend time in natural settings to revive your ability to focus on tasks that demand concentration. Suggestions for individuals

Encourage children to use nature for relaxing and cooling off. Suggestions for individuals

Encourage city planners to plant trees in the inner city. Suggestions for individuals

Support city policies for maintaining trees. Suggestions for individuals

When possible, plant and care for trees near your home. Suggestions for individuals

City planners and arborists should note: the location of vegetation matters.

Caring for trees means caring for people!

To share this information with others Copies of this presentation and other, written materials for nonscientific audiences may be obtained at Copies of this presentation and other, written materials for nonscientific audiences may be obtained at To quote this information in print, please consult the original scientific journal article: To quote this information in print, please consult the original scientific journal article: Kuo, F.E. & Sullivan, W.C. (2001). Aggression and violence in the inner city: Impacts of environment via mental fatigue. Environment & Behavior, 33(4), Available at

On details of the original study Kuo, F.E. & Sullivan, W.C. (2001). Aggression and violence in the inner city: Impacts of environment via mental fatigue. Environment & Behavior, 33, On nature and mental fatigue On nature and mental fatigue Kaplan, R. (1984). Wilderness perception and psychological benefits: An analysis of a continuing program. Leisure Science, 6, Kaplan, S. (1995). The restorative benefits of nature: Toward an integrative framework. Journal of Environmental Psychology, 15, To learn more:

On mental fatigue and aggression Caprara, G.V., Renzi, (1981). The frustration-aggression hypothesis vs. irritability. Recherches di Psychologie Sociale, 3, Kaplan, S. (1987). Mental fatigue and the designed environment. In J. Harvey & D. Henning (Eds.), Public environments. Edmond, OK: Environmental Design Research Association, pp Stanford, M.S., Greve, K.W., Dickens, T.J. (1995). Irritability and impulsiveness: Relationship to self-reported impulsive aggression. Personality and Individual Differences, 19, To learn more:

Other questions? Contact Frances E. Kuo, Ph.D. The University of Illinois at Urbana-Champaign Landscape and Human Health Laboratory 1103 S. Dorner Drive, MC-636 Urbana IL 61801