T he study of delusions has important implications for understanding the role played by affective processes on the road from experience to belief. It can also shed light on the forms of modularity these processes manifest. There are at least two different ways in which emotional processes may be relevant to the etiology of delusional beliefs. First, current models of delusion converge in proposing that such beliefs are based on unusual experiences of various kinds. These unusual experiences are thought to include affective or emotional experiences. For example, it is argued that the Capgras delusion (the belief that a known person has been replaced by an impostor) is triggered by an abnormal affective experience in response to seeing a known person (Ellis & Young, 1990). Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general attening of affective responses to external stimuli (Ellis & Young, 1990), and the seed of the Frégoli delusion (the belief that one is being followed by known people who are in disguise) may lie in heightened affective responses to unfamiliar faces (Davies, Coltheart, Langdon, & Breen, 2001). In delusions of persecution, the experiential component could be an oversensitivity to other people’s disingenuous expressions of emotions (Davis & Gibson, 2000;

LaRusso, 1978). Experience-based proposals have been provided for a number of other delusions (Davies et al., 2001; Langdon & Coltheart, 2000; Maher, 1988; Stone & Young, 1997).