2. What is the savant syndrome and what does it tell us about the nature of intelligence?

Key Points:

• Savants (formerly known as ‘idiots savants’) are individuals with measured IQ in the mentally retarded range who, nevertheless, display a single and exceptional cognitive ability. For example, they might be able to calculate what day of the week any named calendar date falls on (O’Connor & Hermelin, 1984). They might display high musical ability (Sloboda, Hermelin & O’Connor, 1985) or artistic talent (Hermelin & O’Connor, 1990). Or they might be unusually skilled at learning foreign languages (Smith & Tsimpli, 1995) or factoring numbers (Hermelin & O’Connor, 1990).
• An early view of savant skills was that they are based on an exceptionally good but essentially unorganized rote memory system and/or extensive practice (Hill, 1978; Horwitz et al., 1965). More recently, it has been suggested that many savant skills can be explained in terms of an extensive but generative (rather than passive) memory for domain-relevant material (Nettelbeck, 1999; Nettelbeck & Young, 1996; Young & Nettelbeck, 1995).
• There are some problems with the memory explanation of all savant abilities, though. O’Connor and Hermelin (1984, 1992), for example, found that calendrical calculators (those who can calculate what day a particular date falls on) can name days for dates for which no calendar yet exists. They also use abstract rules and structures governing the calendar in order to perform their calculations (Hermelin & O’Connor, 1986). The memory explanation also seems an unlikely basis for artistic talent and for some other calculating abilities, such as the prime-number calculating individual investigated by O’Connor and colleagues (Anderson, O’Connor & Hermelin, 1999; Hermelin & O’Connor, 1990).
• On the other hand, if savants’ feats are accomplished using some kind of automatic or non-thoughtful processing (automatic long-term memory retrieval is the classic example of this), there is no inherent contradiction with the notion of g.
• However, it should be noted that there have even been suggestions of specific forms of memory deficits in autism (see Shalom, 2003, for a recent review).

• Detterman (1996) does argue that savants falsify the idea that there is a single and common ability underlying all intellectual task performance. In so doing, Detterman takes a similar line to that advocated by Gardner (1983), namely that savants prove the fundamental independence of the component abilities that ‘normally’ make up g. However, the abilities that savants display are somewhat implausible candidates as the ‘component abilities’ of Detterman’s theory.
• Anderson ’s theory of the minimal cognitive architecture assumes that the brain damage that leads to savant syndrome has selectively spared some modules from the generalized brain damage that has led to mental retardation in these individuals. It is proposed that these modules come in three kinds: Mark I modules are the full-blown innate variety that most plausibly underlie savant talents in art, music and language. They are represented by all but one of the modules shown in figure 13.2. Mark II modules are the fetch-and-carry mechanisms of cognitive processing, such as long-term memory retrieval, or the ability to recognize mental representations that forms the basis of the ‘theory of mind’ mechanism (Leslie, 1987). Mark III modules are associative processes established after extensive practice, and they are not explicitly represented in figure 13.2. According to Anderson , because savant abilities are modular there is no paradox in their existence in individuals with low IQ, which is a property of thoughtful processing.