Anyone who has watched a clique of third-grade girls overtly ignore another little girl understands the hurt this type of aggression – called social aggression – can inflict upon others. Now a study published in the July/August issue of the journal Child Development finds that this form of aggression, usually an outgrowth of physical aggression, is related more to a child's environment than to his or her genetic background, suggesting that intervention could have a significant effect.
Study researchers from the University of Quebec at Montreal, Laval University, and the University of Montreal, all in Canada, investigated the origins of social aggression through a sample of 234 six-year-old twins. The researchers had the children's peers and teachers rate their physical and social aggression. Overall, researchers found, genetic factors could explain only a small extent of social aggression (approximately 20 percent); the rest is the result of environmental factors such as parental behavior or peer influence.
In contrast, genes account for more than half of individual differences in physical aggression. Most notably, said lead researcher Mara Brendgen, associate professor at the University of Quebec at Montreal, social and physical aggression share most of their underlying genetic factors but show very few overlapping environmental factors.
tratto da Eurekalert - prosegui nella lettura dell'articolo