On the relationship between conceptual knowledge and prejudice about social groups in patients with dementia

OBJECTIVE AND BACKGROUND: Patterns of brain-damaged individuals' deficits in categorizing living versus non-living things indicate separation of semantic knowledge categories in the brain. Recent work in patients with dementia suggested that semantic knowledge about social groups differs from knowledge about living and non-living things. In this study we analyzed patients' social appraisal by testing whether their degree of impairment in social-group knowledge predicted their social-group evaluative reactions (prejudice). We hypothesized that impaired knowledge about social groups would correlate with either heightened or reduced prejudice. METHODS: In Rumiati et al, Cogn Neurosci (2014) http://dx.doi.org/10.1080/17588928.2013.876981, we had given a sorting task to 21 patients with frontotemporal dementia or dementia of the Alzheimer type and 23 healthy controls, to test their knowledge of social groups and living and non-living things. In this study we asked the same participants to evaluate social groups. We used controls' evaluations to rank 20 social groups from extremely negative to extremely positive. We used patients' severity of deficit in sorting social groups to predict the patients' evaluations of the groups, controlling for their levels of deficit in sorting living and non-living items. We also compared the evaluations by patients±deficits in social-group sorting to controls' evaluations. RESULTS: The patients with impaired social-group knowledge evaluated the less-admired groups more positively than did controls, and the more-admired groups less positively. CONCLUSIONS: Impaired social-group knowledge, not a general semantic loss, predicts reduced evaluative bias. Our findings are consistent with neuroimaging evidence for a relationship between semantic and evaluative social-group processes.