Reading others' emotions: Evidence from event-related potentials

This Thesis aimed at investigating, by using the event-related potentials (ERPs) technique, some relevant aspects involved in human ability to read others’ emotions and in empathizing with others’ affective states. Social and affective neuroscience has largely studied faces and facial expressions since they represent relevant “pieces of information” in guiding individuals during interaction. Their importance is strictly related to the fact that they provide unique information about identity, gender, age, trustworthiness, and attractiveness, but they also convey emotions. In Chapter 1, I have introduced the reader to the contents of this Thesis, in particular the ability to “read” others’ facial expressions and to empathize with others’ affective states. In Chapter 2, I have offered an overview of knowledge available today on how humans process faces in general and facial expressions in particular. I have proposed a theoretical excursus starting from Bruce and Young’s cognitive model (1986) to a recent simulative model of recognition of emotional facial expressions by Wood and colleagues (2016), which considers facial mimicry helpful in discriminating between subtle emotions. In Chapter 3 and 4, I have presented two different studies (Experiments 1 and 2, respectively) strongly related to each other, since they aimed both at testing a functional link between the visual system and facial mimicry/sensorimotor simulation during the processing of facial expressions of emotions. I have described two different studies in which ERPs, by virtue of its high temporal resolution, allowed to track the time-course of the hypothesized influence of mimicry/simulation on the stages of visual analysis of facial expressions. The aim of Experiment 1 was to explore the potential connection between facial mimicry and the early stage of the construction of visual percepts of facial expressions; while the Experiment 2 investigated whether and how facial mimicry could interact with later stages of visual processing focusing on the construction of visual working memory representations of facial expressions of emotions, by also monitoring whether this process could depend on the degree of the observers’ empathy. For both studies, the results strongly suggest that mimicry may influence early and later stages of visual processing of faces and facial expressions. In the second part of my Thesis, I introduced the reader to the construct of empathy, dealing with its multifaceted nature and the role of different factors in the modulation of an empathic response, especially to others’ pain (Chapter 5). In Chapter 6 and 7, I have discussed two ERP studies (Experiments 3 and 4a) with one behavioral study included as a control study (Experiment 4b) to investigate the empathic reaction to others’ pain as a function of different variables that could play a role in daily life. Experiment 3 investigated the role of prosodic information in neural empathic responses to others’ pain. Results from this study demonstrated that prosodic information can enhance human ability to share others’ pain by acting transversely on the two main empathy components, the experience sharing and the mentalizing. The aim of Experiment 4a was to study whether the physical distance between an observer and an individual in a particular affective state, induced by a painful stimulation, is a critical factor in modulating the magnitude of an empathic neural reaction in the observer. Thus, by manipulating the perceived physical distance of face stimuli, I observed a moderating effect on empathic ERP reactions as a function of the perceived physical distance of faces. Results of Experiment 4b clarified that the critical factor triggering differential empathic reactions in the two groups in Experiment 4a was not related to the likelihood of identifying the faces of the two sizes but to the perceived physical distance. Finally, in Chapter 8, a general discussion highlights the main findings presented in this Thesis, by also providing future suggestions to extend the research on this topics debated in the previous Chapters.