Differential susceptibility and the early development of aggression: interactive effects of respiratory sinus arrhythmia and environmental quality

Abstract

The purpose of the current study was to predict the development of aggressive behavior from young children's respiratory sinus arrhythmia (RSA) and environmental quality. In a longitudinal sample of 213 children, baseline RSA, RSA suppression in response to a film of crying babies, and a composite measure of environmental quality (incorporating socioeconomic status and marital adjustment) were measured, and parent-reported aggression was assessed from 18 to 54 months of age. Predictions based on biological sensitivity-to-context/differential susceptibility and diathesis-stress models, as well as potential moderation by child sex, were examined. The interaction of baseline RSA with environmental quality predicted the development (slope) and 54-month intercept of mothers' reports of aggression. For girls only, the interaction between baseline RSA and environmental quality predicted the 18-month intercept of fathers' reports. In general, significant negative relations between RSA and aggression were found primarily at high levels of environmental quality. In addition, we found a significant Sex × RSA interaction predicting the slope and 54-month intercept of fathers' reports of aggression, such that RSA was negatively related to aggression for boys but not for girls. Contrary to predictions, no significant main effects or interactions were found for RSA suppression. The results provide mixed but not full support for differential susceptibility theory and provide little support for the diathesis-stress model.

Figure 1

Average mother-reported and father-reported aggression trajectories.

Figure 2

Trajectories of mother-reported aggression (for boys and girls) and father-reported aggression (for girls only). RSA = respiratory sinus arrhythmia.

Figure 3

Simple slopes of environmental quality on the 54-month intercept and the slope of mother-reported aggression at different levels of baseline respiratory sinus arrhythmia (RSA).

Figure 4

Simple effect of environmental quality on the 18-month intercept of girls’ father-reported aggression at different levels of baseline respiratory sinus arrhythmia (RSA).