LAUSR

Abstract This study examined whether being poorly preferred by peers may partially explain why boys with oppositional behaviour develop more conduct problems than girls. Children from the general Dutch population attending regular elementary schools (N = 759, 50.3% boys) were followed annually from age 7 to 10 years. Teachers-rated externalizing behaviour and peer-nominated social preference was assessed across four waves. Autoregressive cross-lagged models indicated that oppositionality predicted increases in conduct problems. Above and beyond this direct link, oppositionality predicted low social preference in subsequent years, which in turn predicted an increase in conduct problems. In this latter pathway, sex differences were found. That is, oppositional boys were as likely as oppositional girls to show an increase in low social preference one year later. However, boys who had low social preference scores showed stronger increases in conduct problems one year later, compared to girls who had low social preference scores. Hence, developmental models of externalizing behaviour should consider the possible sex-differential impact of troublesome peer-relationships to understand the development of milder to more severe externalizing behaviours.