Peer socialization processes in the development of callous-unemotional traits

Callous-unemotional (CU) traits represent a risk factor for persistent, severe levels of externalizing problems. Irritability may predict the development of CU traits for some individuals, who are thought to acquire them in reaction to negative environmental experiences. Models on the development of CU traits have emphasized the socializing role of harsh parenting to the neglect of negative peer experiences. The present study 1) tested primary and alternative models of physical and relational peer victimization as socialization agents in relations between irritability and CU traits; and 2) considered hypothalamic-pituitary-adrenal-axis functioning as a moderator of these associations. Gender moderation was also considered. Aims were tested from middle childhood to adolescence using data from the NICHD Study of Early Child Care and Youth Development, which includes a large national sample (<i>N</i> = 1,077) and multiple methods and informants for the constructs of interest. Positive associations between irritability, peer victimization, and CU traits were supported, with indirect effects on CU traits supported specifically from peer victimization through increases in irritability. Associations between relational victimization, irritability, and CU traits may be particularly salient for females, whose experiences have been neglected to date. However, effects were small, and replication efforts are needed.