Title: The effects of perceivers’ affect and beliefs on social cognition
Description: This dissertation aims to shed light on the ways in which our affective responses and subjective beliefs shape our reasoning about social events and targets. The human ability to reason about other people’s minds, and the social world in which we live, has been central to the field of psychology. However, that ability to make sense of the social world does not exist in isolation. Each social perceiver has idiosyncratic beliefs and identities. Perceivers also affectively respond to events and people in the world around them. Historically, the processes underlying affective processing, social cognition, and formed beliefs, have been studied in isolation, leading to a gap in our knowledge about their interactions. We conducted a set of experiments combining fMRI and behavioral methods to address this gap. The experiments used naturalistic stimuli, which allow related processes to co-occur in an ecologically valid way. The results of the experiments are described in three chapters, following a general introduction (Chapter 1).

In Chapter 2, we show that the mentalizing regions of the brain represent a continuous affective response to social targets, and demonstrate a link between that response and the impression perceivers formed of those targets. In Chapter 3, we demonstrate that when presented with conflicting accounts of the same events, the subsequent event representation in participants medial prefrontal cortex is in concordance with perceivers’ beliefs about the events. In Chapter 4, we describe a cross-disciplinary study, informed by political scientific theories about the roots of polarization. In this study, we challenged partisan’s political beliefs and identities. We found that affective responding brain regions showed an effect of partisan information processing for both ideological beliefs and identity challenges. In addition, using two functional localizer tasks, we identified two sets of regions with differing functional profile within the mentalizing network. One set of regions showed the effect of partisan information processing only when perceivers’ ideology was challenged, while the other set showed the effect only when perceivers’ identity was challenged.

Taken together, the results from these three studies expand our understanding of the mentalizing regions by suggesting that they represent not only the mental states of others, but also an affective response towards them. This work also reinforces our understanding of the differences in level of abstraction of the representation between prefrontal and parietal mentalizing regions. Lastly, the finding of different yet consequential activation profiles within the mentalizing network opens the door for further inquiries into the functional organization and representations within its constituting regions.