Differential Associations between Measures and Dimensions of Inhibitory Control with Aggression in Kindergarten Children

Introduction: Delays or deficits in inhibitory control (IC) in early childhood result in the increased tendency to express high aggression, which has been implicated as a key precursor of problematic behaviors in later life, such as substance abuse, juvenile delinquency, and antisocial behaviors. IC has been variably defined and measured, which may explain its inconsistent findings across studies of young children in associations with behavioral outcomes. Few investigators have comprehensively measured IC using multiple instruments in one study in relation to aggression in early childhood. Elucidating this association, particularly among very young children in high-poverty neighborhoods who are at risk for delays and/or deficits in self-regulation, will have implications for improving their social, emotional, and academic outcomes. In the present study, we hypothesized that different measures of the various dimensions of IC would be differentially associated with aggression in kindergarten children.

Methods: We examined cross-sectional associations between measures (task and observation) and dimensions (motor, behavioral, and cognitive) of IC and aggression to determine which instruments and types of IC are most related. We used baseline data from a school-based intervention study of the PATHS curriculum for high-poverty urban children in kindergarten (n=300, aged 58-83 months). Three neuropsychological tasks measuring IC were used: Peg-Tapping (motor, total correct); Go/No-Go (behavioral, no-go average accuracy), and Delay of Gratification (cognitive, delay in minutes and activity level). Also, a teacher-rated observation of impulsivity was included. Comparisons were made between children with high aggression (at or above the 75^th percentile on the teacher-rated aggressive/oppositional behavior, n=82) and children with low aggression (n=218). We calculated odds ratios, first adjusted for age, sex, and IQ scores, then attention/hyperactivity problem status.

Results: More boys (p<0.01) and children with lower IQ (p<0.05) were in the high aggression group than children in the low aggression group. Children in the high aggression group had fewer correct Peg-Tapping (p<0.05), lower No-Go average accuracy (p<0.05), and higher teacher-rated impulsivity (p<0.001). These associations, except for Peg-Tapping, remained significant even after adjusting for attention/hyperactivity problem status. Delay of Gratification results did not differ by aggression group status.

Conclusions: High-poverty kindergarten children who displayed high aggression exhibited poorer performance in behavioral IC and teacher-rated impulsivity, regardless of attention/hyperactivity issues. Our findings support the need to assess delays/deficits in behavioral IC as an important indicator of aggressive behavior during a critical period of kindergarten children’s neurocognitive development in efforts to prevent these problematic behavior patterns before they become entrenched.