In schizophrenia, the basic experience of existing as a “self” – as a subject whose thoughts, beliefs and actions coincide with what is regarded to be “self” – is disturbed. This has been hypothesised as the distinct phenotypic core of schizophrenia (Sass and Parnas, 2003; Parnas et al., 2005) and the central psychopathological trait marker of psychotic vulnerability (Nelson et al., 2008; Parnas et al., 2005) 'The clinical symptoms come and go,' describes one schizophrenia patient, 'but this nothingness of self is permanently there.' (Kean, 2009)
Anomalous self-experiences (ASEs) provide much of the material for delusional beliefs formed in acute schizophrenia (Stanghellini, 2012). In line with my last post on this blog, I would like to consider whether ASEs might also provide a ‘secondary gain’ or epistemic benefit (Graham, 2013). I will examine one delusion frequently reported by schizophrenia patients, and highly suggestive of an ASE: the delusion of reference.
Delusions of reference are ‘beliefs that a wide variety of neutral events have special significance and refer to the individual personally’ (see Startup and Startup, 2005) A typical example is recounted by Kendler (1999), whose patient R recalls entering a stadium full of people and becoming convinced that he was being watched and applauded by all of them. What underlies a delusion such as this is egocentricity – an ASE entailing a felt “link” between the self and the world inhabited by it (Parnas et al., 2005)
As an abnormality of subjective orientation (Mishara, 2005; Gallagher,1985), egocentric representation (ER) of the self/world relation can be contrasted to allocentric representation (AR), which utilises visual scene context, rather than the self, as the frame of reference for conceptualising the self/world relation (Mishara, 2005)
Delusions of reference demonstrate that ER is capable of “fooling” schizophrenia patients into forming maladaptive beliefs. But what these notorious delusions perhaps obscure, as I will now show, is that ER can also provide unique protections against being “fooled”.
Granted, AR is an extremely practical mode of self-world experience. Without AR, schizophrenia patients experience significant difficulties in using complex visual context to guide action, which results in impaired performance on a variety of tasks, such as those involving perceptual closure of incomplete objects (Doniger et al., 2001) and determination of relative relationships between visual objects (Mishara, 2005)
But AR is not infallible. In tasks where visual context is misleading, AR is disadvantageous. Take the classic Müller-Lyer illusion, pictured below:
The horizontal bar appears longer when the arrowheads are pointing inwards, but in reality both bars are of identical length:
Overcoming the Müller-Lyer illusion requires “filtering out” misleading context provided by the arrowheads – a cognitive strategy that does not come naturally to many. Yet, to schizophrenia patients, whose egocentric self-experience precludes use of this sort of context in the first place, this is no difficulty: they excel at Müller-Lyer tasks relative to “normals” (Parnas, 1999) Indeed, they excel to a degree similar to patients with stroke lesions damaging the ventral pathway, which has led some clinicians to suggest increased reliance on dorsal-stream processing as a cause of ASEs in schizophrenia (Mishara, 2005).
The epistemic superiority of ER to AR on tasks such as the Müller-Lyer challenge can be taken as further evidence that (1) cognitive abnormalities in schizophrenia are context-dependent and, (2) there exists the possibility of a significant positive dimension to psychosis.