Less imitation of arbitrary actions is a specific developmental precursor to callous-unemotional traits in early childhood

Objective Callous-unemotional (CU) traits in early childhood explain heterogeneity within conduct problems and are associated with higher risk for later diagnoses of childhood disruptive behavior disorders and antisocial behavior in adulthood. Emerging research implicates impairments in affiliative processes in the etiology of CU traits. The current study tests whether the imitation of intentional actions with no functional significance -a behavior that supports the acquisition of social conventions and affiliative bonds, is a specific developmental precursor to CU traits in early childhood. Methods Data came from a longitudinal twin study of 628 children (Age 2: 47% females; Age 3: 44.9% females) with observations of arbitrary (i.e., nonfunctional actions) and instrumental (i.e., functional actions) imitation and parent reports of CU traits and oppositional defiant (ODD) behaviors at ages 2 and 3. Results Lower arbitrary imitation at age 2, but not instrumental imitation, was related to increases in CU traits from ages 2 to 3 (beta = -.10, p = .02). Conclusions These findings establish early social and affiliative processes in the etiology of CU traits, highlighting that novel personalized treatment and intervention strategies for CU traits may benefit from targeting these processes to help reduce CU traits and risk for persistent conduct problems in children.