Friends have a strong influence on children's non-physical social aggression -- such as teasing, rumor-spreading and exclusion -- against peers, says a Canadian study that looked at 406 pairs of 7-year-old twins.
The researchers concluded that 77 percent of cases of social aggression among children are driven by friends or even adults, the Canadian Press reported. The findings appear in the journal Child Development.
"Children who hang out with socially aggressive friends seem to pick up this behavior even when they don't have a genetic predisposition to be socially aggressive," said lead author Mara Brendgen, a psychology professor at the University of Quebec in Montreal.
She said socially aggressive habits are easily picked up by children, so parents need to watch for signs of such behavior and to monitor their children's network of friends, the CP reported.
Social attacks tend to peak in early adolescence and can continue into adulthood, Brendgen said.