A recently published study says boys at risk of psychopathy don't react to or join in laughter in the same way that average boys might.
Normally, when people hear laughter, it sets off parts of the brain related to emotion. But for boys at risk of developing psychopathy, their brain reacts in noticeably weaker ways, the study, conducted by researchers at University College London and published in Current Biology, found.
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.Essi Viding, study's lead author
"These findings shed new light on why they often make different choices from their peers," said lead study author Essi Viding in a statement.
"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," she said in an article published by UCL.
But Viding stressed that just because certain boys didn't want to join with other kids' laughter, that didn't mean they would grow up to be antisocial or a danger to others.
Only adults can be psychopaths
"It is not appropriate to label children psychopaths," Viding said. "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."
Children who generally disregarded others, or who are callous and unemotional have traits that researchers can use to detect whether psychopathy could possibly be seen as adults.
Earlier, HuffPost Canada reported on a 2015 Australian study from the University of New South Wales that found that traits associated with psychopathy can be found in children as young as three years old.
That study found that 10 per cent of kids with callous personality traits had difficulty recognizing facial expressions and, when compared to average kids, they were less engaged when they saw others in trouble.
"When they see people in distress, it's not capturing their attention in the same way as it would for the healthy population," said the lead author of that study, clinical child psychologist Eva Kimonis.
Watch: What are differences between how psychopathic women and men attack?
In the UCL study, Viding and her colleagues compared 30 normally behaved kids with 64 teenage boys aged 11 to 16 who either showed one or both traits of being disruptive or displaying varying degrees of callousness.
Researchers exposed them to fake and genuine laughter and then asked them to gauge how much they wanted to join in with that laughter and determine if they thought the laughter was real.
The kids with callous and unemotional traits reported that they had little interest in joining in the giggles, more so than normally-behaved boys or disruptive kids without callous traits.
Callous kids experience the world differently
The findings reveal that children who are at risk of developing psychopathy don't experience the world quite like others do, she said.
In Canada, there could be as many as 300,000 people with psychopathic personalities, the CBC's The Fifth Estate reported. The stats compiled from psychopathy expert Dr. Robert Hare and FBI's law enforcement bulletin found that one per cent of all males are psychopaths and they make up to 20 per cent of prison populations.
The most recent study suggests that future research should lead to longer-term research to better understand at-risk boys and their atypical responses to emotional social cues and how they are related to psychopathy in adulthood.