Savant Memory in a Man with Colour Form-Number Synaesthesia and Asperger Syndrome

Extreme conditions like savantism, autism or synaesthesia, which have a neurological basis, challenge the idea that other minds are similar to our own. In this paper we report a single case study of a man in whom all three of these conditions co-occur. We suggest, on the basis of this single case, that when savantism and synaesthesia cooccur, it is worthwhile testing for an undiagnosed Autism Spectrum Condition (ASC). This is because savantism has an established association with ASC, and the combination of ASC with synaesthesia may increase the likelihood of savantism. The implications of these conditions for philosophy of mind are introduced. The Assumption that all Human Minds are Wired the Same The problem of other minds has been of interest to researchers in fields as diverse as philosophy of mind (Goldman, 2006; Nagel, 1974; Wittgenstein, 1958), developmental and clinical psychology (BaronCohen & Cross, 1992; Baron-Cohen, Golan et al., 2004; Baron-Cohen, Wheelwright & Jolliffe, 1997; Perner, 1991) and neuroimaging (BaronJournal of Consciousness Studies, 14, No. 9–10, 2007, pp. 237–51 Correspondence: Simon Baron-Cohen et al., Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, Cambridge CB2 2AH, UK. Daniel Bor, MRC Cognition and Brain Sciences Unit, 15 Chaucer Rd, Cambridge CB2 2EF, UK. Copyright (c) Imprint Academic 2011 For personal use only -not for reproduction Cohen & Ring, 1994; Baron-Cohen, Ring et al., 2000; Frith & Frith, 1999; Iacoboni et al., 2005). This article focuses on two clinical conditions, autism and synaesthesia, that challenge the assumption that all human minds are wired the same. Even though only one percent of the population at most may have each of these conditions (Baird et al., 2006; Baron-Cohen, Burt et al., 1996), this illustrates a basic problem that there may be other minds that are wired differently at a neuronal level. Neurodevelopmental conditions like autism and synaesthesia invalidate the assumption that all humans share similar conscious experiences because they share similar neural architecture. In the next section, we summarize previous studies of these two neurodevelopmental conditions, before reporting a single case study of a young man who has both. One reason for reporting this case is that currently it is not known how rare or common it is to have both conditions. We wish to encourage other clinicians or researchers to document such cases in order for us to understand if they are related in any way. If each condition separately has a prevalence of 1%, and if these were truly independent, then the probability (p) of them co-occurring would be calculated using the multiplication law: p (synaesthesia) x p (autism) = 0.01 x 0.01 = 1 in 10,000 (i.e. quite rare). However, if they share some common causal mechanism, such as neural overconnectivity (Baron-Cohen, Harrison et al., 1993; Belmonte et al., 2004; Rouw and Scholte, 2007), then they may co-occur more often than chance. Their possible independence or association remains to be tested and epidemiological methods are required to find out if they are related. The single case study we report below in whom both conditions co-occur is all the more interesting because he has a third ‘condition’: savantism. We not only wish to document his unusual profile but also wish to speculate on the relationship between these three conditions. In particular, we put forward the proposal that whenever autism and synaesthesia co-occur, the likelihood of savantism is increased. Such a proposal requires empirical validation through the documentation of further cases.