The functional role of interpersonal dehumanization and associated brain networks

Dehumanization is typically considered as an intergroup phenomenon, whereby people are reduced to less-than-human status on the basis of group affiliations. However, in everyday life, people often disregard the emotional states of others, which could be considered a more subtle form of dehumanization. In this Review, we examine interpersonal dehumanization, which we define as a failure to infer another person’s mental state. First, we describe the functions of interpersonal dehumanization at three temporal scales: as retrospective justification for past moral violations, as a facilitator of present behaviours and as a proactive empathy-regulation strategy. Next, we consider the brain networks that facilitate and influence daily dehumanization: specifically, networks associated with social cognition, empathy and moral decision making. We conclude by suggesting future research directions for the study of interpersonal dehumanization and its implications that could inform the development of concrete solutions to foster more humane and ethical interactions in everyday life. Dehumanization is typically considered as an intergroup phenomenon, but failures to infer another person’s mental state also occur in everyday interpersonal contexts. In this Review, Harris and Delgado describe the functions of interpersonal dehumanization at three temporal scales and discuss their supporting brain networks.