Interpersonal Brain Synchronization In Interpersonal Positive Emotional Contagion

Emotional contagion is a representative social interaction process of interpersonal emotional convergence,in which an individual perceives the emotions of others and generates a similar emotional response.The important theoretical basis of emotional contagion is the mimicry-feedback theory,which suggests that individuals automatically mimic the expressions of others,and then generate similar emotions through peripheral feedback.According to this theory,the mirror neuron system is widely recognized as the neural basis of emotional contagion.Previous studies have mainly focused on the neural mechanisms of emotional contagion from the perspective of one single brain,which makes it difficult to answer how the neural activity of both the sender and the perceiver is coupled to achieve emotional contagion.Among various types of emotional contagion,positive emotional contagion is most likely to occur in interpersonal interactions due to its social affiliation value,and thus,investigating the psychological and neural mechanisms of positive interpersonal emotional contagion has important theoretical and practical significance.Therefore,this study aims to investigate the neural synchronization patterns of positive emotional contagion in a real-life dyadic interaction,and examine whether there are specific intra-brain functional connections and inter-brain synchrony induced by observing others’ happy expressions,as well as whether this neural coupling is related to the effect of positive emotional contagion.In addition,this study aims to provide more complete evidence for the mechanism of interpersonal emotional contagion,with multiple dimensions of measurements,including neural activity,subjective emotional experience,facial expressions,and physiological arousal.This study conducted a within-subject design with a single factor of three levels.The independent variable was the task type of the sender: watching a neutral video,watching a positive emotional video,and performing a non-emotional facial movement based on video instructions.These three levels corresponded to the control condition without emotional contagion,the positive emotional contagion condition,and the control condition with non-emotional facial movement.The perceiver’s task was to observe the sender’s facial movements.A total of 22 pairs of strangers were recruited(7 male pairs and 15 female pairs),with one person in each pair randomly assigned as the sender and the other as the perceiver.Subjective reports were collected to measure the participants’ emotional experience,Face Reader software was used to analyze facial expressions,BIOPAC was used to measure heart rate data and functional near-infrared spectroscopy was utilized to measure neural activity.Cross-correlation was applied to calculate the facial expression synchronization,heart rate synchronization and inter-brain neural activity synchronization between the sender and perceiver,as well as the functional connections within each individual’s brain.The results showed that,compared to observing the non-emotional facial expressions of the sender,when observing the happy facial expressions of the sender:(1)perceiver experienced similar emotional responses and showed synchrony in happy expressions and heart rate,indicating the occurrence of emotional contagion.Furthermore,the stronger the emotional experience of the sender,the stronger the synchrony of the happy expressions between the two individuals.(2)There were specific neural synchronization and functional connectivity within the brain that occurred during emotional contagion,mainly in the mirror neuron system.(3)Among the neural coupling in mirror neuron system,the synchrony between the sender’s right temporal middle gyrus and the perceiver’s left inferior frontal gyrus was positively related to the multidimensional effects of emotional contagion(subjective emotional experience and emotional expression).(4)The functional connectivity between the perceiver’s angular gyrus and the mirror neuron system is negatively related to the occurrence of emotional contagion.However,the stronger the intensity of the happy expression of the sender,the weaker the functional connectivity involved in the perceiver’s angular gyrus.In summary,this study draws the following conclusions: when the perceiver observes the happy expression from the sender in real time,the sender and perceiver mainly show synchronized neural activity in the mirror neuron system.These neural synchronizations are significantly positively related to the emotional contagion effect,indicating the importance of neural synchronization of mirror neuron system in the occurrence of positive emotional contagion.In addition,in the functional connection between the perceiver’s mentalizing system and the mirror neuron system,the perceiver’s differentiation of self and other mental processes may hinder the occurrence of automatic emotional contagion based on mimicry-feedback.However,the stronger the sender’s positive emotional expression and the weaker the functional connection between the perceiver’s mentalizing system and the mirror neuron system,the more likely it is for automatic emotional contagion to regain the advantage.