A new social dilemma experiment shows that punishment is not an effective way to get members of society to cooperate for the common good.
The result has implications for understanding how cooperation has evolved to have a formative role in human societies, according to researchers.
In theoretical studies, punishment is often seen as a way to coerce people into being more cooperative.
To examine that theory, a team of international researchers led by Marko Jusup of Hokkaido University in Japan and Zhen Wang of Northwestern Polytechnical University in China conducted the social dilemma experiment.
The experiment investigated if providing punishment as an option helps improve the overall level of cooperation in an unchanging network of individuals.
The researchers used a version of the commonly employed “prisoner’s dilemma” game. In China, 225 students were organized into three trial groups and played 50 rounds of the game.
In group one, every student played with two opponents, who changed every round. The students could choose between “cooperate” or “defect” and points were given based on the combined choices made. If a student and the two opponents chose “defect,” the student gained zero points. If they all chose “cooperate,” the student gained four points. If a student chose to defect while the other two chose to cooperate, the gain for the student was eight points.
The second group was similar to the first in every aspect except that the people playing the game with each other remained the same for the duration of the 50 rounds, enabling them to learn each other’s characteristics, the researchers explained.
In the third group, players also remained the same. However, a new option, “punish,” was introduced. Choosing punishment led to a small reduction in points for the punisher and a larger reduction of points for the those who were punished.
At the end of the game, overall points were counted and the students were given money based on the number of points won.
The expectation is that, as individuals play more with the same opponents over several rounds, they see the benefit of cooperating in order to gain more points, according to the researchers.
Introducing punishment as an option is saying: If you don’t cooperate with me, I’ll punish you, the scientists explain. In theory, it is expected that applying this option would lead to more cooperation.
The researchers found that players in the constantly changing groups cooperated much less (four percent) than those in the static groups (38 percent), where they were able to establish which players were willing to cooperate and gain a larger average financial payoff for all involved.
Surprisingly, however, adding punishment as an option did not improve the level of cooperation (37 percent). The final financial payoffs in this trial group were also, on average, significantly less than those gained by players in the static group, the researchers reported.
Interestingly, they say, less defection was seen in the punishment group when compared to the static group as some players replaced defection with punishment.
“While the implied message when punishing someone is ‘I want you to be cooperative,’ the immediate effect is more consistent with the message ‘I want to hurt you,'” write the researchers in the study, which was published in the journal Proceedings of the National Academy of Sciences.
Punishment seems to have an overall demoralizing effect, as individuals who get punished on multiple occasions may see a good chunk of their total payoff vanish in a short period of time, explain the researchers. This could lead players to lose interest in the game and play the remaining rounds with less of a rational strategy, they note.
The availability of punishment as an option also seems to reduce the incentive to choose cooperation over competition, the researchers point out.
Why, then, is punishment so pervasive in human societies?
“It could be that human brains are hardwired to derive pleasure from punishing competitors,” Jusup said.
“However, it is more likely that, in real life, a dominant side has the ability to punish without provoking retaliation,” Wang added.
Source: Hokkaido University
Photo: In the first group (Well-mixed) where the opponents were reshuffled each round, defectors prevailed over the course of 50 rounds. In the second group (Network reciprocity) where the opponents remained the same for the 50 rounds enabling them to identify cooperative neighbors, the cooperative cluster survived. In the third group (Network reciprocity with punishment), the option to punish opponents failed to boost cooperation. Credit: Xuelong Li, et al., Proceedings of the National Academy of Sciences of the United States of America, December 19, 2017..