By Jean Balchin 20/12/2017

Both chimpanzees and  six-year-old children love seeing punishment doled out, even if it costs them, according to a paper published online this week in Nature Human Behaviour. These findings reveal new insights about the evolution of peer-punishment as a means to enforce social norms and ensure cooperation.

We know from previous research that humans and some animal species experience empathetic distress and concern when seeing others harmed. Adult humans however have also been shown to experience feelings of pleasure –  when the harm is perceived as a deserved punishment for antisocial actions.

“In humans, empathic reactions can be radically undermined and change to feelings of pleasure when the suffering victim was previously antisocial or perceived as an outgroup member.”

Natacha Mendes, Nikolaus Steinbeis and colleagues at the Max Planck Institute for Human Cognitive and Brain Sciences devised an ingenious experiment to test when human children develop a motivation to see punishment happen. The team also set out to explore whether the same motivation exists in our closest living relatives, chimpanzees.

The children and chimpanzees were each introduced to a character who shared food or a toy with them (prosocial) and one who withheld these (antisocial). These characters then received physical punishment out of the view of the participants, who could choose to pay a cost to witness the punishment. For children, the “cost” was valuable stickers; for chimps, physical effort.

It was found that chimpanzees and six-year-olds were more motivated to see antisocial others punished than prosocial others. Four- or five-year-old children however were not similarly motivated. Moreover, it was found that six-year-old children showed a greater mixture of positive and negative emotions in response to watching the punishment of the antisocial agent than they did for the prosocial one.

The combination of these emotions, rejoicing in the misfortune of a disliked other, is also known as Schadenfreude.

This evidence supports the notion that the sixth year is an important time in human emotional and cognitive development, when children become willing to sacrifice resources in the interests of fairness. That chimpanzees share this personal motivation to see fair punishment enacted suggests deep evolutionary roots as a strategy to maintain fair cooperation.