Differential Susceptibility and Firstborn Child Adjustment After the Arrival of a Second Child: Firstborn Child’s Temperament as a Moderator

Abstract

The number of studies examining parenting-by-temperament interactions is rapidly growing, however most of these studies focused either on negative or positive predictors, and child adjustment. Therefore, the current longitudinal study (N = 77 two-parent families) examined whether parental warmth as well as parental hostility is related to the developmental outcomes (internalizing, externalizing and prosocial behavior) of firstborn children after the transition to siblinghood and whether this relation is affected by temperament traits of the firstborn child. Two of the most influential models were tested against each other: the differential susceptibility hypothesis (increased sensitivity of an individual to both supportive and negative environments) and diathesis-stress model (increased sensitivity of an individual to negative environments). Parenting was assessed using both self-reports and video-observations. No support for the differential susceptibility hypothesis and the diathesis-stress model was found. However, results showed that children with a more difficult temperament – compared to those with a less difficult temperament – did not seem to benefit from maternal warmth and expressed higher levels of internalizing problem behavior.