Less Empathic and More Reactive: The Different Impact of Childhood Maltreatment on Facial Mimicry and Vagal Regulation.

Martina Ardizzi,Maria Alessandra Umiltà,Valentina Evangelista,Vittorio Gallese,Alessandra Di Liscia,Roberto Ravera,Nouchine Hadjikhani

doi:10.1371/journal.pone.0163853

Martina Ardizzi, Maria Alessandra Umiltà + Show 5 more

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https://doi.org/10.1371/journal.pone.0163853

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Abstract

Facial mimicry and vagal regulation represent two crucial physiological responses to others’ facial expressions of emotions. Facial mimicry, defined as the automatic, rapid and congruent electromyographic activation to others’ facial expressions, is implicated in empathy, emotional reciprocity and emotions recognition. Vagal regulation, quantified by the computation of Respiratory Sinus Arrhythmia (RSA), exemplifies the autonomic adaptation to contingent social cues. Although it has been demonstrated that childhood maltreatment induces alterations in the processing of the facial expression of emotions, both at an explicit and implicit level, the effects of maltreatment on children’s facial mimicry and vagal regulation in response to facial expressions of emotions remain unknown. The purpose of the present study was to fill this gap, involving 24 street-children (maltreated group) and 20 age-matched controls (control group). We recorded their spontaneous facial electromyographic activations of corrugator and zygomaticus muscles and RSA responses during the visualization of the facial expressions of anger, fear, joy and sadness. Results demonstrated a different impact of childhood maltreatment on facial mimicry and vagal regulation. Maltreated children did not show the typical positive-negative modulation of corrugator mimicry. Furthermore, when only negative facial expressions were considered, maltreated children demonstrated lower corrugator mimicry than controls. With respect to vagal regulation, whereas maltreated children manifested the expected and functional inverse correlation between RSA value at rest and RSA response to angry facial expressions, controls did not. These results describe an early and divergent functional adaptation to hostile environment of the two investigated physiological mechanisms. On the one side, maltreatment leads to the suppression of the spontaneous facial mimicry normally concurring to empathic understanding of others’ emotions. On the other side, maltreatment forces the precocious development of the functional synchronization between vagal regulation and threatening social cues facilitating the recruitment of fight-or-flight defensive behavioral strategies.

Highlights

Childhood maltreatment, defined as “any act of omission or commission that results in harm or the potential for harm, regardless of intent” [1], represents a substantial threat to victims’ social skills development
Strong associations between childhood abuse and externalizing problems, such as aggression and conduct disorders [5], as well as a tendency among abused children to show low rates of prosocial behaviors [6], have been extensively established. These clinical observations are supported by numerous studies demonstrating, both at an explicit and implicit level, specific alterations in social cues processing, like facial expressions of emotions, among maltreated children and adolescents
Post-hoc comparisons conducted on the main effect of Emotion revealed that corrugator EMG activity recorded in response to joy facial expressions (-0.09 μV, SE 0.16) was significantly lower than corrugator EMG activity measured in response to both angry (0.63 μV, SE 0.20; p = 0.03), and fear facial expressions (0.75 μV, SE 0.25; p = 0.01)

Summary

Introduction

Childhood maltreatment, defined as “any act of omission or commission that results in harm or the potential for harm, regardless of intent” [1], represents a substantial threat to victims’ social skills development. Strong associations between childhood abuse and externalizing problems, such as aggression and conduct disorders [5], as well as a tendency among abused children to show low rates of prosocial behaviors [6], have been extensively established. These clinical observations are supported by numerous studies demonstrating, both at an explicit and implicit level, specific alterations in social cues processing, like facial expressions of emotions, among maltreated children and adolescents. Angry facial expressions are identified on the basis of less sensory inputs [9,10] and thanks to fewer expressive cues by physically abused children than controls [11]

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