This study investigated the role of autonomic nervous system (ANS) coordination in response to emotion in girls’ and boys’ development of relational (e.g., ignoring, excluding) and physical (e.g., hitting, kicking) aggression. Caregivers reported on children’s relational and physical aggression at ages 6, 7, 8, and 10 years (N = 232, 50.4% girls, 46.6% Latinx). Sympathetic nervous system (assessed via pre-ejection period) and parasympathetic nervous system (assessed via respiratory sinus arrhythmia) reactivity were measured in response to video clips depicting fear, happiness, and sadness at age 7. Growth curve models indicated that ANS reactivity to sadness, but not to fear or happiness, was related to trajectories of relational aggression. In contrast, ANS reactivity to all three emotions was associated with trajectories of physical aggression. Effects differed across genders, indicating that distinct patterns of ANS reactivity to emotion may be involved in girls’ and boys’ development of aggression. Overall, these findings contribute to a growing literature documenting the role of ANS reactivity to emotion in aggressive behavior. Moreover, this study considers ANS reactivity to specific emotions, as related to both relational and physical aggression, and as differentially expressed among girls versus boys.

Unresolved loss/trauma in the context of the Adult Attachment Interview (AAI) has been theorised to result from dissociative processing of fear-related memories and ideas. To examine the plausibility of this model, this study tested hypothesised associations between unresolved loss/trauma and indicators of autonomic nervous system (ANS) reactivity. First-time pregnant women (N = 235) participated in the AAI while heart rate (interbeat interval; IBI) and indicators of parasympathetic reactivity (respiratory sinus arrhythmia; RSA) and sympathetic reactivity (pre-ejection period; PEP, skin conductance level; SCL) were recorded. Using multilevel modelling, ANS reactivity was examined in relation to topic (loss/trauma versus other questions); discussion of actual loss/trauma; classification of unresolved/disorganised; and unresolved responses during the interview. Responses to loss/trauma questions and discussion of loss were associated with respectively larger and smaller IBIs. There was no moderation by unresolved/disorganised status. Unresolved responses about loss were associated with smaller IBIs. Participants classified as unresolved/disorganised showed decreasing PEP and blunted SCL throughout the whole interview. The findings suggest that unresolved speech about loss co-occurs with physiological arousal, although the inconclusive findings regarding parasympathetic and sympathetic nervous system responses fail to clearly support the role of fear.

Adverse childhood experiences (ACEs) have an impact on women's adaptation to parenthood, but mechanisms are poorly understood. Autonomic nervous system reactivity was tested as a potential mediating mechanism in a sample of 193 at-risk primiparous women. ACEs were measured retrospectively during pregnancy. A baby cry-response task was administered during pregnancy while indicators of sympathetic reactivity (pre-ejection period; PEP) and parasympathetic reactivity (respiratory sinus arrhythmia; RSA) were recorded. Parenting self-efficacy, anxiety, and depressive symptoms were measured during pregnancy and 1 year after giving birth. Harsh discipline was measured 2 years after giving birth. Structural equation modeling was employed to test whether baseline PEP and RSA and reactivity mediated links between ACEs and postnatal outcomes, adjusted for prenatal variables. High ACEs predicted less RSA reactivity (p = .02), which subsequently predicted increases in depressive symptoms (p = .03). The indirect effect was not significant (p = .06). There was no indirect link between high ACEs and harsh parenting through PEP nor RSA (n = 98). The parasympathetic nervous system may be involved in negative affective responses in the transition to parenthood among women exposed to childhood trauma.