Freeloading friends rock the boat
The idea of a happy, cooperative society in which no one gets punished falls apart as soon as a few freeloaders show up, a new study shows.
Although most volunteers in the study first chose to join a group that did not use punishment, most eventually left for a group that fined transgressors.
The study can help us understand how to make society work more smoothly and can help in designing policies aimed at ensuring cooperation, writes Assistant Professor Joseph Henrich, a US anthropologist at Emory University in Georgia, in a commentary.
"Even if nearly everyone is initially cooperative and contributes, free-riders can profit and proliferate, leading to the eventual collapse of cooperation," he writes.
For example, if most people in society are brave or conserve petrol, he explains, others benefit by evading military service or driving petrol-guzzling cars.
In the study, researchers asked 84 students to join one of two groups to play a game with tokens. One group of players punished members who did not share freely, while the other group did not.
The students could choose which group to join.
"Each player is endowed with 20 money [tokens] and may contribute between 0 and 20 [tokens] to a public good," the researchers write.
"Each group member equally profits from the public good, independent of his or her own contribution."
In the punishment group, members could choose to fine other members three tokens, but it cost them one of their own tokens to do so.
Two-thirds of the students initially chose the group in which members could not punish others, but many abandoned that group when they saw those in the punishment group were prospering more.
And former freeloaders were some of the most enthusiastic converts to the punishment mode, the researchers found.
"You can't explain this dramatic change in behaviour by saying that people are just looking for the best pay-off. People gave up pay-off to follow the cooperative norm," says Erfurt researcher Dr Bettina Rockenbach.
Punishing the freeloaders
Dr Bernd Irlenbusch of the London School of Economics adds he was surprised with the extent of punishment.
"I was surprised so many of the freeloaders exerted punishment on others when they entered the sanctioning institution," he says.
When the game ended after 30 rounds, the people in the punishment group had donated an average 18 tokens per round.
Meanwhile the live-and-let-live group had almost no members and those who remained donated three tokens to the public good on average per round.
Little actual punishment was applied during the later rounds of the game, apparently because the threat of punishment was enough to ensure cooperation, the researchers say.