Friday, February 29, 2008

Autism:a cognitive style and not a deficit

Continuing with the theme of my last post, I'll like to highlight an important review article by Happe, in which it is argued that Autism is a different cognitive style and not should not be thought in terms of underlying deficits, but that strengths be also recognized and given equal footing.

The major thesis of the article lies heavily on the 'Weak central coherence' theory of Autism, as per which the Autistics have a cognitive style dominated by local processing at the expanse of the gestalt and which claims that Autistics use too little of context in interpreting information/ percepts. There is a lot of data on which the above is based and I suggest that one read the TICS review in its entirety. For those who prefer snippets instead, here goes:

One current account of autism proposes that a different, rather than merely deficient, mind lies at the centre of autism. Frith, prompted by a strong belief that assets and deficits in autism might have one and the same origin, proposed that autism is characterized by weak ‘central coherence’. Central coherence (CC) is the term she coined for the everyday tendency to process incoming information in its context – that is, pulling information together for higher-level meaning – often at the expense of memory for detail. For example, as Bartlett’s classic work showed, the gist of a story is easily recalled, while the detail is effortful to retain and quickly lost6. Similarly, global processing predominates over local processing in at least some aspects of perception. This preference for integration and global processing also characterizes young children and individuals with (non-autistic) mental handicap who, unlike those with autism, show an advantage in recalling organized versus jumbled material. Indeed, recent research suggests that global processing might predominate even in infants as young as three months.

Frith has suggested that this feature of human information- processing is disturbed in autism, and that people with autism show detail-focused processing in which features are perceived and retained at the expense of global configuration and contextualized meaning. Clinically, children and adults with autism often show a preoccupation with details and parts, while failing to extract gist or configuration. Kanner, who named autism, commented on the tendency for fragmentary processing in relation to the children’s characteristic resistance to change; ‘...a situation, a performance, a sentence is not regarded as complete if it is not made up of exactly the same elements that were present at the time the child was first confronted with it’. Indeed, Kanner saw as a universal feature of autism the ‘inability to experience wholes without full attention to the constituent parts’, a description akin to Frith’s notion of weak CC.

Because weak CC provides both advantages and disadvantages,it is possible to think of this balance (between preference for parts versus wholes) as akin to a cognitive style – a style that might vary in the normal population. There might perhaps be a normal distribution of cognitive style from ‘weak’ CC (preferential processing of arts – for example, good proof reading), to ‘strong’ (preferential processing of wholes – for example, good gist memory). There is existing but disparate evidence of normal individual differences in local versus global processing, from infancy, through childhood43, and in adulthood. Sex differences have been reported on tasks thought to tap local versus global processing, although studies have typically confounded type of processing (local versus global) and domain (visuospatial versus verbal). The possibility of sex differences in coherence is intriguing in relation to autism, which shows a very high male to female ratio, especially at the high ability end of the autism spectrum. Might the normal distribution of coherence in males be shifted towards weak coherence and local or featural processing? Perhaps there is an area of increased risk for autism at the extreme weak coherence end of the continuum of cognitive style – individuals who fall at this extreme end might be predisposed to develop autism if unlucky enough to suffer the additional social deficits (impaired theory of mind) apparent in this disorder.

Preliminary results suggest that parents, and especially fathers, of children with autism show significantly superior performance on tasks favouring local processing: they excel at the EFT (Embedded Figure Task), at (unsegmented) block design, and at accurately judging visual illusions. They are also more likely than fathers in the other groups to give local completions to sentence stems such as, ‘The sea tastes of salt and..?’ (‘…pepper’). In all these respects they resemble individuals with autism, but for these fathers their detail-focused cognitive style is usually an asset, not a deficit. These results fit well with work by Baron-Cohen and colleagues, which showed that fathers of children with autism are fast at the EFT, and over-represented in professions such as engineering.

All this is consistent with this Blog's focus on Autism and Psychosis as opposite ends on a continuum of cognitive and social style.

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1 comment:

Gilbert Wesley Purdy said...

I can only hope that Francesca Happe's approach can be expanded upon. The position that Autism is a "cognitive style" rather than a "deficit," is, I think, resoundingly correct, but she deals in savantism and abstraction rather than practical examples at the statistical mean. The non-savant has a "cognitive style" as well and is far and away the more common case.

Furthermore, Happe's Autistic is too locked-in. If he or she is on the high-functioning end of the spectrum, detail-processing over cc-processing is a strong tendency rather than a locked-in cognitive-style. HFAs and those with Aspergers alter their brains through learning as do neurotypicals. I submit that routes to central coherence are available and that the high functional can come to perceive a unique and valuable coherence not readily available to those with more "normal" brains.

In time, we may even find that low-functional Autistics are not so profoundly disabled as we presently believe. We may just lack sufficient understanding in order to build the necessary bridge to the neurotypical world. On the other hand, they may be the deeply sad transitional result of evolution. Only time will tell. The most important thing is that we remember that they are people.