Roots of rebellion The role of children's temperament and genetics in disruptive behavior and parenting

Disruptive behavior in children includes disobedience, verbal and physical aggression, defiance, and irritability. Although such behavior can be part of normal development, it usually decreases as children grow older. When disruptive behavior persists or worsens, however, it can lead to more serious developmental and behavioral problems. Early intervention is therefore essential, which requires understanding the factors that contribute to the development and maintenance of disruptive behavior.
This dissertation had two main aims. The first was to examine the relationships between parenting, temperament, stress reactivity, and children’s disruptive behavior, while also considering families’ socioeconomic status. I found that in toddlers, harsh parenting, negative emotionality, and disruptive behavior increased together over time, but we found no evidence that these factors reinforced one another. In children aged 4 to 8, I found that negative emotionality and harsh parenting predicted later disruptive behavior. However, parenting did not depend on children’s temperament, regardless of socioeconomic background.
The second aim was to investigate whether differences in children’s responses to a proven effective parenting intervention could be explained by temperament and/or genetic characteristics. Findings showed that neither temperament nor genetic makeup influenced the intervention’s effectiveness: the Incredible Years program reduced disruptive behavior regardless of these traits. However, the intervention also led to decreases in both negative emotionality and disruptive behavior. This challenges the view that temperament is static and unchangeable. Instead, it suggests that temperament—specifically negative emotionality—can be influenced by parenting, highlighting the importance of evaluating parenting interventions in terms of their effect on other important predictors of child outcomes.