The impact of social categorization on the representation of people
1 Center for Economics and Neuroscience (CENs)
Social categorisation is associated with attitudes towards social groups that include ingroup bias, stereotyping or dehumanisation, which in turn facilitate behaviours like social support, discrimination or aggression. This categorisation influences even early stages of social interactions, such as face perception: ingroup faces evoke di;erent neural responses than outgroup faces, whether the groups are racial or arbitrary. We hypothesised that revealing the category (here: study fields) of students would lead fellow students to categorise them into in- vs. out-group members. Categorisation should be reflected in changes of pairwise similarity between these individuals. In a withinsubject design, 20 participants were shown the faces of eight unknown students. Participants rated the pairwise similarity between these students based on facial features, social life, and personality. After the students’ study fields were revealed, participants repeated the similarity ratings. We found that after revealing the study fields, the average similarity between students of the same field increased, while the average similarity between students of di;erent fields decreased. These findings were found in similarities of personality or social life, but not in similarities of facial features. These results show that knowing the study field of students leads to them being categorised into two distinct groups by fellow students. In a pre-registered study, we are currently repeating the experiment accompanied with measures of the fMRI BOLD signal evoked during presentation of the student faces before and after knowing the study field. We expect that changes in neural representations of these faces will mirror the behavioural changes we observed.