%A Edward H. Hagen %T Intraspecific Exploitative Mimicry in Humans %X Non-bizarre psychotic delusions are hypothesized to be psychological adaptations which evolved to mitigate the dangerous consequences of social exclusion and ostracism. When we lived in small, kin-based groups, delusions would have functioned to combat social exclusion by closely mimicking conditions, such as external threats or illness, where fellow group members were likely to cooperate and provide assistance. If delusions are adaptations to social exclusion, then they should onset when an individual faces a serious social threat, they should function (in ancestral type environments) to prevent exclusion-at least in the short term-and they should cease when the social threat ceases, an hypothesis which is examined in the context of numerous published studies of Delusional Disorder (DD). %D 1995 %K human, evolution, adaptation, delusions, psychosis, mimesis, parasitism, ostracism, evolutionary psychology, psychiatry, psychopathology, mental illness, schizophrenia, vigilence, anthropology, deception %L cogprints756