Qualifying Broken Windows Theory in the Lab

brokendownloadThis post is based on a paper by several scientists at the Max Planck Institute for Research on Collective Goods. It is a merging of several things that I have been interested in over the years:  social psychology, public good economics, city planning, and epidemiology (at least in a metaphoric sense).  Politicians loved the simplicity of “broken windows,” and I was willing as a city planner to use it if it got more resources for what I wanted. Being tough on crime was an easier sell than normal city planning administration.

William Bratton has been credited with reducing crime in both New York and in Los Angeles,  where he explicitly relied on the “broken windows” policy. The approach was inspired by an experiment conducted by Philip Zimbardo in 1969. Zimbardo simultaneously placed two otherwise identical cars in public spaces, one in the Bronx, the other in Palo Alto. Neither car had license plates, and the hood was open. Within 26 hours the car in the Bronx was totally pillaged and destroyed, while the Palo Alto car stayed pristine for an entire week. Once the experimenters themselves broke a window with a hammer, it went to ruins within hours, even in the prosperous Californian town.

The paper tests two key components of the broken windows theory: (1) depending on first impressions people make in an environment, they behave differently. Metaphorically speaking, the first broken window changes a neighborhood. (2) If individuals quickly realize that their attempts at antisocial behavior trigger a sanction, this tames antisocial behavior.

In the field, the fact that the window is not fixed also gives a signal to those who have always been living in the area. They may read this as evidence that social cohesion is eroding. Yet normally they have many more sources of information, from which they draw their personal conclusions. They talk to each other, they read the local newspaper, they address themselves to the authorities. Therefore, in the field the effect of the signal is hard to identify. Equally hard is identifying the motives of those who seem to behave differently. Do they move to another neighborhood simply because they can afford it, because they want to send their children to a better school, because a new street has brought another suburb within reach – or do they move out to protect themselves from the perceived risk of crime?

To avoid such identification problems, in the experiments reported in this paper the authors create an artificial neighborhood. The experimental setting exposes participants to a social dilemma. Individually, each participant is best off if the remaining group members contribute to a joint project while she free rides. Participants interact in a randomly composed group of four over ten announced periods. This design provides a clean measure of (anti-)social behavior. The less a participant contributes, the more she is selfish, and the more she imposes damage on the remaining group members.

In the experiments, participants are exposed to a dilemma. Players interact repeatedly for 10 periods in groups of size four. The situation is fully symmetric, which all participants know.
Thus each period each participant receives 20 tokens from the experimenter. She is free to keep
all of them, or to invest them partly or fully in the joint project. Each token she keeps gives her 1
token. Each token she invests only gives her 0.4 tokens. Yet she also receives 0.4 tokens for every token any other group member has invested into the project. Hence the entire group gains 1.6 tokens from each token invested. A participant is best off if all others have contributed fully, while she has contributed nothing. She then has 20 – 0 + 0.4*60 = 44 tokens. She is worse off if all others have contributed nothing while she alone has invested fully. She then has 20 – 20 + 0.4*20 = 8 tokens. If all contribute their entire endowments, all have 20 – 20 + 0.4*80 = 32 tokens. If all keep their entire endowments, all have 20 – 0 + 0 = 20 tokens.  The authors conducted five such experiments and analyzed data from twenty three other experiments.

The results are summarized (and oversimplified for this post) in Figure 6 above.  The impact of first impressions and early punishment are similar at the outset, but by round 7, early punishment no longer has a statistically significant impact.

For the first research question, the explanatory variable of interest is the impression  participants happen to gather in the first period. This is operationalized as the mean contribution by the remaining three group members, in the first period. The experimenters then measure the causal effect of first impressions on contributions in later rounds. First impressions do indeed have strong explanatory power. The effect does not collapse with participants’ individual social value orientation, as expressed in participants’ own contribution to the public project in the first round of interaction, i.e. while they are unaware of the cooperativeness of the remaining members of their group. The average amount the remaining group members have contributed in the first round explains their choices until the next to last round; in the final round, selfishness wins the day, even with participants who were willing to support the joint project in earlier periods. The effect is visible for participants who have contributed more, and for those who have contributed less than the average of their groups in the first period. It thus is not confined to those strongly, or to those little socially minded.

For the second research question, the explanatory variable is reactions to antisocial behavior in the first round of interaction. Controlling for first impressions, the effect is small in early rounds, and becomes insignificant in later rounds. The critical cause is first impressions, not early vigilance.  In public perception, broken windows policies have been associated with being tough on crime, and on petty crime and disorder short of criminal infraction.  The authors see these things as at most a secondary cause. If free riders realize that crime and disorder have consequences, they behave better. This, in turn, gives others a better impression.

In the experiments, just a few coins are at stake and other matters are simplified. In the field, the inhabitant of a neighborhood in decay may have to leave the house in which she was born, she may see her property burglarized, and may even fear for her life. In the field, through the power of fear, small initial disorder may easily start a vicious cycle. One such story might be: initial signs of disorder cause fear. Residents stay at home. This weakens social control. First offenders invade the  neighborhood. Even more residents refrain from actively maintaining order. Serious criminal activity is pulled to the neighborhood. So it is noteworthy that, in the  much less dramatic experimental setting, first impressions have a long lasting impact.

The message to policymakers is straightforward based on the experiments. Money spent
on impression management is likely to be money well spent. Still good first impressions are not strong enough by themselves, so for cooperation to be sustainable, vigilance and enforcement are necessary. However, sanctions alone are also not sufficient. Being determined to prosecute culprits is thus not enough. It is more important to fix the windows.

Beckenkamp, M; Engel, C; Glockner, A; Irlenbusch, B; Hennig-Schmidt, H; Kube, S; Kurschilgen, M; Morell, A; Nicknlish, A; Normann, H; Towfigh, E (2013). “First Impressions are More Important than Early Intervention Qualifying Broken Windows Theory in the Lab.” Preprints of the
Max Planck Institute for Research on Collective Goods, Bonn 2009/21.

Zimbardo, P (1969). “The Human Choice. Individuation, Reason, and Order versus
Deindividuation, Impulse, and Chaos.” Nebraska Symposium on Motivation 17: 237-307.