The cognitive neuroscience of group membership

The aim of the present study was to uncover the neural basis of group membership, and investigate whether the brain represents the ‘in-group’ differentially to the ‘out-group’. It was hypothesised that a network of brain regions including the cortical midline structures (CMS) and the temporal gyrus, would show enhanced activation for social words versus non-social words. It was also hypothesised that of these regions dedicated to the ‘social brain’, there would be unique neural activity in the medial prefrontal cortex for words associated with the in-group. To test this, participants were asked to identify which groups they felt they belonged to, and which groups they felt they did not belong to. In addition to the pre-existing groups, newly created groups were formed (the red team and the blue team). In a second session, functional magnetic resonance imaging (fMRI) was then used to identify the brain regions that the participants used to process in-group words, out-group words, red team words, blue team words, and living and non-living (non-social) words. The results supported the first two research hypotheses for the pre-existing groups, revealing a network of brain activity specific to social words compared to non-social words, and in-group words compared to out-group words. This pattern of brain activity was not replicated for the newly created groups, suggesting that group membership represents significant meaning and is not easily recreated within a laboratory