Asperger's disorder is a subtype of autism, characterized by deficits in social interaction, delays in nonverbal communication and possibly also deficits in nonverbal IQ (such as on a test known as Block Design). However, a new study in Brain and Cognition challenges this latter claim - with surprising results.
Hayashi et al gave 17 children with Asperger's a test of fluid intelligence called the Raven's Progressive Matrices. Fluid intelligence is thought to reflect problem-solving ability, to show large individual differences, and to be a distinct construct from general intelligence ("g"). The results showed that these children performed better on the Raven's Progressive Matrices test than 17 age- and sex-matched controls, and that these results seemed to be driven by superior fluid intelligence among male children with Asperger's.
The authors conclude that subjects with Asperger's may have superior left lateral prefrontal function, and that future research should focus on understanding the precise cognitive correlates of improved fluid intelligence.
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17 is pretty small. Were the Aspies matched for class? If upper-middle or upper class people are more likely to have Aspies, and they're more likely to be smart, then it could just be a biased sample.
And fluid intelligence and "g" are basically the same construct. Gustafsson (sp?) did a factor analysis that showed fluid intelligence had a g-loading of 0.98 or something really high like that. It's in Jensen's book, The g Factor.
Posted by: agnostic | November 9, 2007 6:19 PM
While agnostic's concerns are important, I wouldn't be surprised if the results bear out. It depends on how severe the Asperger's is. Simon Baron-Cohen (not Sacha, I think his cousin) has a theory that autism is merely the far end of a natural spectrum of thinking styles. On one end, a stereotypically female style of thinking is an "intuitive" style that takes a lot of information into account at once. On the other end is a stereotypically male style of analysis, thinking step-by-step and using logical rules to decide how the results of one step of analysis should lead to another. One end of the spectrum is more focused on wholes, the other on parts.
On this view, it wouldn't be surprising to find that asperger's spectrum kids would be better at certain types of tasks, at least if those kids aren't too far to that end of the spectrum. Fluid intelligence seems to me to be linked to step-by-step analytic ability. The superior lateral PFC would be just part of an overall different mode of preferred brain operation.
I found this theory appealing when we discussed it in a graduate level cognitive development class; few papers made it out of that class with their credibility intact. I should also specify that I (and I think Baron-Cohen) aren't saying that women think one way and men another; just that there's a small difference in average thinking style, with a great deal of overlap.
Posted by: Seth Herd | November 13, 2007 2:25 PM
IQ is vaguely related to attention and shifting ability - both which are thought by one camp (eg Clancy Blair) to be components of 'working memory'. In the other camp, (eg Jensen) memory capacity is the sole factor involved with 'working memory'. Whether fluid intelligence is or is not the same as g depends on how one chooses to define the construct of fluid intelligence. What is for certain is that any form of human intellectual productivity requires some degree of attention and shifting ability.
Measures of g (IQ, 'intelligence') are almost pure measures of memory bandwidth (perhaps with the exception of the Raven's - although I recall one study showing that even the Raven's was 'polluted' with Vc). In the mainstream, the concept of attention and shifting 'ability' are assumed, somewhat unwisely (as the aspie study attests - not to mention child prodigies and Michael Jackson - suggest), equivalent to g. More work will have to be done to understand the evolutionary mechanisms regulating attention/shifting, and exactly how these mechanisms assist in high level problem solving ability (uhm..Intelligence).
Posted by: zadeh79 | December 9, 2007 12:30 AM