The Role of Siblings in Emotion Reactivity for Preschool-Aged Children

Abstract

Background: Emotion reactivity and regulation are underlying mechanisms of social-emotional functioning. Social learning theory and family systems theory suggest that sibling relationships may contribute to emotion processing development via repeated opportunities to engage in emotion expression and modification during frequent interactions. The present study aimed to elucidate how siblings influence emotion processing by examining children’s emotion reactivity via intra-individual patterns of dynamic change in Respiratory Sinus Arrhythmia (RSA), a physiological biomarker of emotion regulation, while preschool-aged children experienced an emotion-eliciting stressor in the presence of a sibling, in comparison to experiencing the stressor while alone and in the presence of a novel adult. Methods: Participants included 48 sibling dyads (target Mage=3.89, SD = 0.48; sibling Mage=6.40, SD =0.91) and their caregiver. The younger sibling wore a heart rate monitor throughout data collection procedures and mean RSA values were calculated for each 30-second epoch across the baseline and emotion eliciting segments. A two-level growth curve model was employed to examine intra-individual patterns in RSA reactivity across the three conditions. Results: Results indicated that the level-2 random slope model significantly fit the data, suggesting that a significant proportion of variance in reactivity can be attributed to individual differences. However, there were no changes in RSA reactivity on average. Hypothesis testing indicated that there was no significant difference in RSA reactivity across the three conditions, which suggests that sibling presence did not significantly impact physiological reactivity. Discussion: Findings offer important methodological considerations, measurement implications, and future directions for understanding the role of sibling relationships on emotion processing development.