Boys with psychopathic tendencies make less effort to laugh with other children, a study has found.
The research, published in the journal Current Biology, found that boys at risk of psychopathy in adulthood do not find laughter contagious.
Brain scans also showed they had a lower response to other people's laughter. Being unemotional and lacking empathy is apparently linked to developing psychopathy in later life.
The children who did not find laughter contagious also showed reduced brain activity in areas linked to co-operation with others.
Professor Essi Viding, a study author, said:
It is not appropriate to label children psychopaths.
Psychopathy is an adult personality disorder.
However, we do know from longitudinal research that there are certain children who are at a higher risk for developing psychopathy, and we screened for those features that indicate that risk.
She also said that these children experience the world and interactions differently:
Those social cues that automatically give us pleasure or alert us to someone’s distress do not register in the same way for these children.
That does not mean that these children are destined to become antisocial or dangerous; rather, these findings shed new light on why they often make different choices from their peers.