Increased residential greenspace is associated with decreased aggressive behaviorsThis study examined the potential association between residential neighborhood greenspace and aggressive behaviors in adolescents living in urban areas in southern California. A total of 640 families participated in the study yielding data on 1287 adolescents (ages 9-18) who had at least 2 assessments of aggressive behaviors. The families -- representative of the ethnic and socioeconomic diversity of the greater Los Angeles area – were drawn from the Risk Factors for Antisocial Behavior Study involving a multi-ethnic cohort of twins and triplets born in 1990 to 1995.
Data collection measures included longitudinal assessments of aggressive behaviors over the preceding 6 month period using the parent version of the Child Behavior Checklist, and neighborhood greenspace surrounding participant residences using the Normalized Difference Vegetation Index derived from satellite imagery. Also collected, through structured interviews and questionnaires, was information on family sociodemographic factors and neighborhood quality.
Findings indicated that more residential greenspace within a 1000-meter buffer was associated with decreased aggressive behaviors in urban-dwelling adolescents. These associations -- observed with both short-term (one to six month) and long-term (one to three year) exposures -- could not be explained by sociodemographic factors (age, gender, race/ethnicity, socioeconomic status) or neighborhood quality as assessed by parent reports on such factors as criminal and gang-related activities, unemployment, vandalism, and substance abuse in the local area. Neighborhood noise (related to such factors as traffic density and proximity to freeways and roads), temperature, and maternal risk factors (such as smoking and depression) were also considered in the data analysis and were ruled out as confounding factors.
Overall the results of this study indicate a consistent pattern of decreased aggression associated with increasing residential greenspace. The short-term benefit of increasing vegetation over the range common in urban areas was equivalent to 1.9 to 2.2 years of age-related behavioral maturation, while the long-term benefit was equivalent to 2.1 to 2.5 years of age-related behavioral maturation. The authors explore several possible explanations for their findings. While the exact mechanism by which greenspace may reduce aggressive behavior has not yet been identified, these findings attest to the value of providing greater access to greenspace as a strategy to reduce aggressive behavior in urban environments.
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