Relations of age to cognitive and motivational elements of impulse control in boys with and without externalizing behavior problems.

In a cross-sectional study of 83 unmedicated boys, 6 to 16 years of age (M = 10.6, SD = 2.1), attending public (N = 48) and therapeutic schools for behaviorally disturbed children (N = 35), we examined relations of externalizing psychopathology to age-dependent change in performance on cognitive and motivational dimensions of impulse control assessed by laboratory tasks. When we controlled for internalizing symptoms and IQ or school achievement, all children showed improving competence with increasing age on both dimensions over the age range of the sample. Children with externalizing problems performed more poorly on both dimensions at all ages than children without such problems. Comparing age-dependent competence for the two groups, a model of convergent maturation in cognitive aspects of impulse control, and a model depicting a stable deficit in motivational aspects of impulse control in those children with externalizing behavior problems, relative to those without such problems, emerged. Studies of individual growth in impulse control, together with correlates of growth, are needed to validate these observations.