Atypical Minds: the Cognitive Science of Difference and Potentialities
Cognitio 2015
Young researchers conference in cognitive science
Montréal, June 8th, 9th and 10th 2015
The Erotetic Theory of Delusional Cognition
Matthew Parrott & Philipp Koralus.
In cognitive neuropsychology and neuropsychiatry, it is typical for both schizophrenia and delusions to be characterized in terms of an abnormality in a subject's ability to reason (e.g., Coltheart et. al., 2011; Davies and Egan 2013; Garety and Freeman, 1999). There is strong empirical support for this characterization. First, widely replicated studies have shown that both delusional subjects and subjects with schizophrenia exhibit a tendency to 'jump to conclusions' on probabilistic reasoning tasks (Huq et. al., 1988; Garety, et. al. 2005; Garety and Freeman, 1999, Fine et. al., 2007; cf. So, et. al. 2012, Langdon, et. al. 2010). Second, in spite of some recent research highlighting cognitive or neurobiological disturbances that plausibly contribute to the generation of certain monothematic delusions (Stone and Young, 1997, Blakemore et. al., 2002, Kapur, 2003), evidence indicates that abnormal reasoning is also implicated in the onset of these delusions (for review see Coltheart et. al. 2011 or Bell et. al. 2006). Finally, recent experiments suggest that schizophrenic subjects exhibit irregular performance on reasoning tasks involving conditionals, including better performance than controls on certain problems (Mellet et. al. 2006).
To improve our understanding of these irregular patterns of reasoning behavior, we need to understand precisely how the reasoning capacities of psychiatric subjects differ from those of normally functioning individuals. Yet, existing theoretical models have failed to offer a clear picture of this. Investigations of reasoning in delusional and schizophrenic subjects have largely been conducted from within a Bayesian framework (Davies and Egan, 2013; Fine et. al. 2007; Parrott, forthcoming). In such framework, human reasoning consists in cognitive processes governed by the probability calculus because the Bayesian approach conceives of the aim of reasoning as solving informational problems in conditions of uncertainty (Oaksford and Chater, 2007). Despite the widespread popularity of this Bayesian approach in the cognitive sciences, we will argue that it faces serious challenges.
The primary objective of this paper is to argue for a novel account of one cognitive factor implicated in delusional cognition, which we call the erotetic theory of delusional cognition. Specifically, we shall propose that a less inquisitive version of a question/answer process that has been independently proposed to account for ordinary reasoning underlies delusional thinking (Koralus and Mascarheans, 2013). More specifically, the erotetic theory of delusion holds that a central cognitive factor in delusion is impaired endogenous question raising. What this means is that delusional and schizophrenic subjects raise the same sorts of default questions as typical individuals, but with fewer alternatives envisaged or with fewer follow-up questions. In particular, we suggest that these patients have a much lower tendency to raise questions that would depend on abandoning or modifying the initial question directly prompted by what is presented to them. Delusional and schizophrenic subjects are simply less inquisitive
We also argue that the erotetic theory has considerable advantages over alternative models of the cognitive factor in delusion, specifically Bayesian models. More specifically, we argue that the erotetic theory offers a superior explanation of both the onset of the Capgras delusion and of the experimentally observed patterns of reasoning exhibited by delusional and schizophrenic subjects. Finally, we claim that the erotetic theory can make much better sense of the fact that psychiatric patients can in fact manifest improved reasoning performance, relative to non-psychiatric populations, in certain cases.