Cognitive theories of delusion formation: The contribution of visual scanpath research

Recent findings from visual scanpath research are considered in relation to cognitive theories of delusion formation. Contemporary theories converge in proposing that both perceptual and cognitive aberrations are crucial to the development of delusional beliefs (Garety and Freeman, 1999). Deluded individuals have reliably demonstrated attributional and probabilistic reasoning biases, manifesting as hasty decision making and an inclination to blame other people for negative experiences (Bentall, Kinderman, and Kaney, 1994; Garety and Hemsley, 1994). Deluded people have also displayed attentional preference for threat-related material and a 'negative' world view (Kaney, Wolfenden, Dewey, and Bentall, 1992; Kaney, Bowen-Jones, Dewey, and Bentall, 1997). In combination, these biases might reflect a general tendency for deluded individuals to 'jump to conclusions' when evaluating others' intentions (Garety and Freeman, 1999), influenced by the perception of threat and persecution everywhere (Kaney et al., 1997). This thesis would be consistent with reports of an inability of paranoid patients to correctly infer the intentions of others during 'theory of mind' tasks but would not predict a total lack of mentalising ability as proposed by Frith (1992). In visual scanpath paradigms, deluded schizophrenics tend to display excessive staring behaviour and to avoid gazing at facial features when viewing human faces (Phillips and David, 1997, 1998; Streit, Wolwer, and Gaebel, 1997; Williams et al., 1999). These abnormal scanpath strategies could underlie aberrations in social reasoning (including misinterpretation of others' intentions) and data gathering exhibited by deluded individuals. Exploration of the relationship between visual scanpaths and biases in social cognition is therefore warranted.