The interactive effects of infant activity level and fear on growth trajectories of early childhood behavior problems.

The current study examined the interactive effects of infant activity level and fear on growth trajectories of behavior problems in early childhood (age 4 to 8 years) using maternal ratings. The sample was drawn from the National Longitudinal Survey of Youth (NLSY) and included children who were between 1 and 11 months in 1986. Findings suggested that boys characterized by high activity level and low levels of fear in infancy escalated in both externalizing and internalizing symptoms. Also, boys characterized by high fear and low activity level increased in internalizing symptoms and these effects seemed to be specific to depression rather than anxiety. Temperament did not predict escalation in externalizing symptomatology for girls, but low levels of fear predicted increases in internalizing symptoms. There was also evidence for a decline in depression specific symptoms for girls characterized by high fear and low activity in infancy. These findings suggest the importance of examining interactive models of temperament risk and considering gender specific pathways to behavior problems.