The impact of social information on emotional learning

Sammanfattning: Our survival is contingent on our ability to observe and interact with conspecifics. For example, by observing the facial expressions of others, we can vicariously learn to avoid potentially dangerous events without first-hand personal exposure, thus reducing the risk of harm. Furthermore, through direct social interactions, such as when we exchange facial expressions with another individual, we learn how to optimize our behavior, and thereby avoid dangerous social outcomes. Despite the large corpus of research on face perception and spontaneous responses to static faces, little is known about responses to faces in dynamic, naturalistic situations, and there are no studies that have examined how goal directed responses to other’s faces are affected by learning during dyadic interactions. Additionally, the underlying neurobiological processes governing learning in social settings remain largely unstudied. To shed light on these phenomena pertaining to observational learning and decision-making processes in real-life, interactive settings, involving facial expressions, this thesis first aims at investigating how our endogenous opioid system can influence how we learn to associate threats to different stimuli in response to others' facial expressions exhibiting painful reactions (Study I); and to study the learning mechanisms of optimizing facial expression exchange when deciding to either form a smile or a frown during interactive dyads in order to avoid aversive outcomes (Study II). Furthermore, we tested whether the learning process of optimizing one’s facial expression selection in interactive dyads was influenced by the interactant’s facial dominance (Study III). In brief, Study I, showed that learning about threats through observing others is regulated by opioid receptors on a neuronal basis. In Study II, we developed a novel method to study facial interactions based on online biofeedback using EMG signals. Our results validated our method, showing that participants learned to optimize their facial behavior to avoid punishment, and we replicated earlier findings of faster and more accurate responses in congruent vs. incongruent conditions. Moreover, participants performed better on trials when confronted with smiling, as compared to frowning, faces, suggesting it might be easier to adapt facial responses to positively associated expressions. In Study III, we found that facial dominance influenced the optimization process of facial expression selection in both punishment and reward learning contexts. Taken together, our findings highlight the role of specific neurobiological and social-cognitive factors in aversive learning in social situations.