Kids with conservative parents are more likely to punish wrongdoers from outside their own groups than kids with liberal parents, a new study has found.

While the reverse is true for transgressors from within – kids with liberal parents more likely enforce norms, even at a cost to themselves, than the offspring of conservative types.

“From an early age, children are willing to pay a personal cost to punish others for violations that do not affect them directly,” the study, published in journal Psychological Science, says.

“People may punish to enforce cooperative norms (amplifying punishment of in-groups) or to express anger at perpetrators (amplifying punishment of out-groups).”

A few experiments were ran involving kids aged three to eight, in which they were made to associate with victims and transgressors, then asked whether to dish out punishments to the latter, at a cost to themselves.

For example, in one experiment they were shown a child from another city (an out-group) tearing up a picture drawn by a child from their own city (in-group). The child was then asked whether to close the playground slide not only for the transgressor, but themselves. 

In this experiment and others like it, kids of conservative parents were more likely to punish the transgressor from the out-group than kids of liberals, while kids of liberals were more likely to punish people from their own group. 

Punishment rates were about the same in both groups of kids – neither was more willing to punish, at a cost to themselves, than the other – but who they were willing to punish differed. 

“Our findings support the possibility that children of more conservative parents are more willing to punish out-group members due to out-group hostility rather than in-group favouritism,” the study said.

“These children were particularly unlikely to want to play with out-group transgressors.”

As for why kids of liberal parents were more likely to punish their in-group peers: “We speculate that the behaviour of children of more liberal parents reflects a desire to maintain norms of fairness and reciprocity within their group (or alternatively, heightened feelings of in-group shame.)”

The researchers said the findings were expected, and “illustrate that values and attitudes transmitted intergenerationally influence how people respond to moral transgressions within and outside of their communities”. 

Even as young as age three.