Family Functioning and Intraindividual Reaction Time Variability Interactively Predict Children’s Externalizing Problems

Abstract Intraindividual reaction time variability (IIV), which serves as an index of attentional control, was related to externalizing problems. However, it remains unknown whether children’s IIV interacts with family functioning, including family adaptability and cohesion, to predict their externalizing problems. The present study examined this concern. Participants included 168 (M = 7.35 years, SD = .48; 48% boys) and 155 (M = 8.32 years, SD = .45; 49% boys) children at the first (T1) and second (after one year, T2) measurements, respectively. At T1, a flanker task was used to assess children’s IIV. Mothers reported the Chinese version of the Family Adaptability and Cohesion Scales and the Chinese version of the Child Behavior Checklist. At T2, mothers reported children’s externalizing problems again. Results indicated that family functioning negatively and IIV positively correlated with children’s externalizing problems. Furthermore, family functioning interacted with children’s IIV to predict their externalizing problems concurrently and longitudinally. Specifically, low family functioning combined with greater IIV predicted prospective externalizing problems. Findings suggested that better attentional control (indexed by low IIV) may buffer the negative effect of poor family functioning.