ANÁLISIS DE RESISTIVIDAD DE TERRENO

In the case of the first area outlined above, where individuals have domain-specific disabilities, it is proposed that these individuals may have defective/faulty or inefficient modular cognitive architecture, and that this is the primary cause of their specific pathology. For example, in the case of autism, it has been suggested that individuals have a deficit/defect in the working of a so-called 'Theory of Mind' module, evident in specific inabilities to understand others' beliefs, desires and intentions, that, in normal children, is supposed to start working at about 18 months^ (Leslie, 1987 ).

For those individuals with specific abilities (not only idiot savants, but also individuals of normal intelligence who may have exceptional abilities in one area), the suggestion is that they may have highly efficient cognitive architecture dedicated to one domain which is unaffected by more general intellectual deficits. Consequently, these individuals are able to perform at, or above, normal levels (Anderson, 1992).

In general, exploration of the abilities and disabilities of clinical populations (an approach known as the study of Developmental Psychopathology) has yielded interesting and important evidence for domain-specific and potentially modular human processes. The advantage of studying these populations is that individuals' abilities or disabilities are relatively easy to identify. However, a major practical disadvantage, is that such clinical populations are small in number. For example. Idiots Savants who do not also display autistic symptomology^® represent only 0.06% of the population of

^ There are however alternative explainations why autistic individuals may have such problems with mental states. It may be that they have in a primary inability (from birth) to engage interpersonally with others (Hobson, 1993).

It is of important note that in autism the incidence of Idiot Savant abilities is around 10% which is higher than in general mental retardation. The reason why I am excluding these individuals from this particular discusision is because such autistic individuals appear to have specific intellectual

Section One___________Chapter One: Perception, Cognition and Information Processsing / page 37 Mentally Retarded individuals, who in themselves represent between 2-3% of the whole populations^ (Hill, 1978).

Of course, it might be asked why, if such abilities are modular and expected to be unaffected by general intellectual impairments, is their prevalence so low? Why is it that more mentally retarded individuals do not show such spared abilities ?

In answer to such a question, there are two points to bear in mind. The first is based on the fact that, most often, the abilities of idiot savants are exceptional Their abilities seem to reflect a superior level of performance in the domain in question, even in relation to normal individuals. One would expect, even in the normal population, for such superior modular functioning to be rare. Thus, one would also expect such an ability would be rare in mentally retarded individuals, and consequently that the prevalence would be low. Secondly, one would expect that general intellectual deficits will act to obscure or impair the expression of such abilities making them harder to identify. This latter point is of particular relevance to this thesis, and is expanded upon when considering experimental methodology in Chapter Two.

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The approach adopted in this thesis is similar to the approach adopted in studies of the capacities of Idiot Savants, insofar as the clinical population involved has specific impairments in general intellectual-cognitive processing which can be contrasted with potentially 'normal processes that may employ domain-specific, modular cognitive architecture. How it differs, is that this study explores modular capacities that all

profiles that differ from those seen in general mental retardation. These profiles do not allow one to confidently conclude that such abilites are unrelated to intellectual functioning.

The incidence of mental retardation depends, of course, on the current diagnostic criteria. This changed as recently as 1973 when the AAMD changed the diagnostic criteria for mentally retarded individuals from having an IQ one standard deviation below the mean, to having and IQ two standard deviations below. Ovenight this 'cured* 26 million American people of mental retardation (Zigler & Hodapp,I986).

Section One___________Chapter One: Perception, Cognition and Information Processsing / page 38 mentally retarded (and indeed non-retarded) individuals might be expected to possess. Capacities that have previously been proposed to be related to general intelligence and therefore assumed to be impaired in mentally retarded individuals because of their general intellectual impairments.

An examination of the three theoretical approaches to perception and cognition earlier in this chapter has highlighted a number of areas of common theoretical ground between two of them -the ’Gibsonian' and the "Modular" approaches, particularly in relation to the importance afforded to person-related meanings, and the directness of some perceptual processes. For example, with respect to this issue, Fodor postulates that candidates for modules may include :

"...task specific 'higher level' systems concerned with the visual guidance of hodily motions or the recognition of faces of con-specifics."(Fodor, 1983, p 47) ..and, in parallel, Gibson suggests that...

"the richest and most elaborate affordances of the environment are provided hy other animals and, for us, other people."(Gihson, 1979, pl3S)

Consequently, both Fodor and Gibson are proposing direct perceptual mechanisms for processing human-related information. Whereas Gibson might propose that we directly resonate to this information, Fodor would say that we employ "innately" determined input systems that, through a process of inference, deliver meanings related to the stimulus. If Fodor and Gibson are right in emphasising the importance of person- related information, and Fodor and Anderson are correct in asserting that such perception may employ processes unrelated to central, intellectually based capacities, then one can predict that mentally retarded individuals may as be capable of processing such person-related information as normal individuals. This is the central proposition of this thesis.

Section One: Theoretical issues Chapter Two / Page 39

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Chapter One outlined a number of theoretical issues regarding perception, and was concerned with the relationship between 'thoughtful' and perceptual processes. This chapter is also concerned with these issues, but is more specific in its focus, and deals with the relationship between thoughtful, intellectual processes and person perception. Thus, in this chapter I attempt to fulfill two objectives. One objective is to assess the degree to which experimental studies provide sufficient evidence to support the proposal that mentally retarded people (individuals believed to have deficits in thought and problem solving) have person-perceptual impairments. Before this, however, we must pursue the other objective and more fully explicate the nature of Mental Retardation and of'Intelligence'.

2 .1 . Me n t a l Re t a r d a t i o n a n d Ge n e r a l In t e l l e c t u a l

Fu n c t i o n i n g.