Individuals who directly confront violators of social norms aren't rewarded by their peers for disciplining the violator, a new study finds. Data also showed that females who littered were nearly five times more likely than were males to be chided for the infraction. These findings result from the first experiment to test the prevalence of direct and indirect punishment in the field, and are part of broader research that seeks to understand how humans cooperate in one-time interactions.

Nikos Nikiforakis, NYU Abu Dhabi associate professor of Economics, along with Professor Loukas Balafoutas of the University of Innsbruck and Professor Bettina Rockenbach of the University of Cologne, coauthored the paper, which was recently published in the Proceedings of the National Academy of Science.

Nikiforakis has been interested in cooperation — or lack of cooperation — since he was a child in his native Greece. "I grew up in this environment in which you'd have a traffic light and a very long line of cars waiting to turn, and you'd have a car jump the queue," he said. "And nobody would say anything, except maybe for me."

Social scientists have difficulty comprehending why strangers choose to cooperate. Wouldn't two strangers, who may never see each other again, approach an interaction simply as an opportunity to fleece the other and maximize personal gain? Economic and biological theories support this bleak vision.

But in real life, in airports, train stations, and marketplaces, strangers somehow find a way to get along.

Theories posit that cooperation is enforced by the punishment of selfish behavior by members of society. Punishment can be direct, whereby an individual confronts another; or it can be indirect, whereby an individual simply withholds a reward from the transgressor. Nikiforakis offered a familiar example: if a coworker acts rudely, you could confront him and tell him to stop (direct punishment), or you could simply not invite him to your next party (withholding reward).

There are benefits to both courses of action. Direct punishment makes it clear that a social norm has been transgressed, and confrontation can be a route to reconciliation. A disciplinarian may also gain social capital from peers for confronting a transgressor.

But direct punishment has its costs: it takes time, energy, and can lead to retaliation. Withholding reward is the safer — cheaper, in economic terms — way to discipline. "If you think about both of these theories of punishment together, it is not obvious why I would choose to confront you and punish you for violating a social norm when I can just withhold reward," Nikiforakis said.

And yet, people do engage in direct punishment; thus, there must be some reason that drives individuals to engage in this more costly behavior. So, Nikiforakis and his coauthors set out to determine if punishers are rewarded by their peers.

In the Field
The researchers set up their experiment in the two busiest train stations in Cologne, ensuring that interactions occurred between strangers.

They hired drama students to act out roles in four "treatments." In the first, a violator discarded a paper coffee cup on the platform. The violator was verbally reprimanded by another actor, called a punisher. The punisher then dropped his or her bag of books in front of an observer, who had no knowledge that an experiment was being conducted. The researchers measured the number of times observers helped the punisher pick up the books, which was considered a reward.

In the second treatment, an actor who had neither violated a norm nor punished a violator dropped books in front of an observer, providing the researchers with a baseline rate of helping. The third treatment measured how often an observer helped a violator pick up his or her books after the violator littered. The fourth treatment measured the rate at which an observer directly punished a violator who littered.

The experiment uncovered some fascinating findings. "We saw that people who punish aren't more likely to be rewarded than the average person who dropped books," Nikiforakis said. "And we found that people who violated were much less likely to be helped than normal people or even punishers. Some people still helped violators, but it was a very small number." And though women were more likely to be subjected to direct punishment for littering, men did not go unpunished, but were punished indirectly.

"We find evidence for both the theories of direct and indirect punishment, but we find that when you put the two together, withholding reward seems to be the preferable option because costly punishment has the risk of retaliation," Nikiforakis concluded.

Looking Forward
Nikiforakis and his coauthors are working on future field experiments that will help them better understand why people adhere to social norms. “The fear of punishment is one reason people may cooperate with strangers, but it is almost certainly not the entire story,” Nikiforakis said. “We need to understand why people adhere to social norms. This will help us understand when formal laws are needed to improve social outcomes, and how these laws should be.”

Header photo appeared in the paper: Loukas Balafoutas, Nikos Nikiforakis, and Bettina Rockenbach. “Direct and Indirect Punishment among Strangers in the Field.” Proceedings of the National Academy of Sciences, October 27, 2014.