Genetic and environmental links between children's temperament and their problems with peers.

Peer relationships become central to children's development as they develop social skills and theory of mind in their early development. We investigated the role of temperament in children's peer problems. Mothers of three-year-old twins (N=759 pairs) rated their children's temperament using the EAS scale (1) and children's peer problems using the Strengths and Difficulties Questionnaire (2). Children's peer problems were positively associated with their negative emotionality, and related negatively to their sociability and activity level. Genetics contributed to individual differences in temperament and peer problems, with peer problems substantially heritable (44%). The remaining variance is attributed to environmental factors. Genetic factors largely mediated the correlations between peer problems and temperament.The findings point to the importance of children's temperamentally-based characteristics in their social development.