Starting in the1980s New York City police took a zero-tolerance approach to cracking down on moderate misdemeanors like litter or graffiti. The move was based on the so-called, "broken windows theory,” that disorderly, unkempt neighborhoods attract crime. The crackdown contributed to a significant crime decrease, although follow-up studies suggest that police presence itself was the key.

Now research reveals that there’s a link between a neighborhood’s appearance and the perception of safety. The work is in the Journal of Personality and Social Psychology.

Scientists presented photos of 20 neighborhoods to nearly 150 volunteers. After seeing the photos, the subjects were asked to rate the strength of ties between residents and their ability to protect the neighborhood against crime. These ratings were compared with those of actual residents. And the subjects’ impressions strongly matched the perceptions of the actual residents.

The researchers also asked about trust, and determined that the better the neighborhood looked, the more the subjects trusted the residents. They concluded that disorder can lead to distrust, which may discourage cooperation between neighbors.

Interestingly, in neighborhoods with vegetation, the amount of well-kept grass most correlated with a good rating of the social environment. So increasing urban green space may have far-reaching positive effects.

—Christie Nicholson