Wednesday, September 3, 2008

Thoughts on the "Extreme-Male-Brain" Theory of Autism

I've been skeptical of Simon Baron-Cohen's Extreme Male Brain theory of autism ever since I first heard about it; my thought then was that, even granting that there are two distinct, gender-specific cognitive styles, the likelihood is much greater that autistic cognition would differ radically from both than that it would resemble one or the other.

(I think the example I was reading about when I had that thought was navigation: supposedly, men navigate using a mental map, while women use landmarks. "Well," I thought, "I navigate by playing a mental video of myself walking the route I'm supposed to take." Landmarks are part of it, but equally important is remembering turns and orientation. And both of those approaches are a lot more abstract than mine --- the archetypal man constructs a mental map he works from, and the archetypal woman remembers a list of landmarks. I record a complete visual memory of myself walking the entire route, and play bits of it back at will. It's less efficient, but more comprehensive.)

Over the course of the long article I linked to in the first paragraph, Baron-Cohen develops a concept of the male brain autistics are supposed to exemplify: it excels at mathematical reasoning, navigation and spatial reasoning, spotting single elements within larger visual wholes (e.g., the Embedded Figures Task), rotating objects, and aiming and targeting projectiles, and does poorly at verbal tasks, inferring another person's state of mind, cooperation and social judgment. It is also more strongly lateralized than the female brain, with a smaller corpus callosum and more exaggerated handedness. The female brain, by contrast, specializes in language, empathy and cognitive dexterity (e.g., rapidly coming up with a list of objects that are blue, or a list of words beginning with a given letter, or quickly categorizing or matching objects).

As Baron-Cohen suggests, this theory would quite neatly wrap up the past decade's major observations about autistic cognition: deficits* in theory of mind, central coherence and executive function. As defined above, Baron-Cohen's "male" brain type encompasses all three of these: poor theory of mind is practically written into the definition of the male brain (it is, after all, defined in opposition to the highly empathic female brain), so that one's a freebie; weak central coherence is evident in the male brain's focus on detail at the expense of broader patterns, and you would expect executive function to be weaker in someone with a strongly lateralized, weakly interconnected brain than in someone whose brain is more unified.

Unless Baron-Cohen can prove that all these variables (sex, language ability, empathy, brain lateralization, autism etc.) are directly related, all his theory will have accomplished will be redefining normal maleness as a state of mild autism. So far, the evidence is inconclusive. Yes, the few male-female differences in cognitive style that exist (male advantage in mentally rotating 3-D objects, female advantage in verbal fluency) are consistent with Baron-Cohen's ideas of the male and female brains, but other areas he predicted would show differences haven't, or have shown them inconsistently (empathy, mathematical and language ability, interest in social vs. mechanical stimuli) --- and even the differences that have been shown to exist are small ones, with a substantial zone of overlap between the sexes.

Language ability is also quite readily shown to be independent of social understanding by the example of Asperger syndrome. Baron-Cohen conflates autism with Asperger syndrome in his article, and speaks of both as involving a delay or impairment in language acquisition and use. This isn't true; one of the diagnostic criteria for Asperger syndrome is that language acquisition must occur on time or precociously. Baron-Cohen places AS on a continuum between the normal male brain and the "classically autistic" brain, which is problematic given AS's normal or superior verbal capacities and its higher male-to-female ratio (9:1, as opposed to 4:1 in classical autism).

Neuroanatomically, the theory is on ground as shaky as it is in cognitive psychology. Baron-Cohen invokes differences in the size of the corpus callosum to explain the contrast between the strongly lateralized male brain and the adapatable, bilateralized female brain, ascribing the female advantage in verbal fluency to speedy communication between hemispheres. Unfortunately, this 1997 meta-analysis of 49 studies and this current study indicate that there is no difference between male and female corpora callosa that cannot be accounted for by overall differences in brain size --- which favor men. Also, autistic people (who are definitely less fluent overall in their use of language than NTs) tend to display very weak brain lateralization and handedness, which Baron-Cohen acknowledges.

I can understand the appeal of a theory relating male gender and autism --- it would explain both the preponderance of men on the spectrum and the trouble many female autistics have fitting into the feminine social role. I think it would ultimately obscure more than it illuminated, though, both about autism and about the nature of gender. Defining maleness as mild autism would enshrine in biology a very culturally specific ideal of geeky masculinity, and legitimize (again, via biology) the delegation of all familial and relationship responsibilities to women, who, after all, have specialized nervous systems that can handle all that stuff.

*Autism research tends to find "deficits" in autistic cognition wherever it goes looking for them, even when the actual results indicate an autistic advantage --- e.g., findings that we tend to do better on visual-search tasks getting interpreted as showing "defects in central coherence," "can't see the forest for the trees."


Ettina said...

It's my impression that autistic men have plenty of trouble fitting into gender roles, too. I mean, unathletic geeky boys who get upset easily don't tend to fit male gender roles very well.

Lindsay said...

I think they do, too. That complicates the whole "autistics are just like normal men, only more so" thesis. If it were true that autism differed from normal maleness only in degree, you would expect to see autistic men having an easier time with masculinity than autistic women have with femininity (since both autistic men *AND* women are supposedly hypermasculine). I do not think this is the case; I think autistic members of both sexes struggle equally with gender roles.

Beastinblack said...

What would be 'the extreme female brain' then? Would that have its own set of issues? If genetic variation exists the so should the other extreme.

Lindsay said...

Baron-Cohen mentions the "female" brain type in the article I link, but does not discuss its extreme version. Two other researchers, Bernard Crespi and Christopher Badcock, have written a paper proposing that, as autism is to the "male" brain, psychosis (particularly schizophrenia) is to the "female" brain.

If, as I understand Baron-Cohen to be saying, the "male" type of brain is geared toward understanding systems and the "female" type of brain is geared toward empathy (i.e., discerning feeling and intention in other people's demeanor or actions), then someone with an "extreme female brain" would be a whiz at mind-reading and stumped by systems. They might try to interpret *everything* as if it were some kind of message.

Lindsay said...

I did find a bit of clarification from Simon Baron-Cohen's book, The Essential Difference, on the gender-stereotypes question:

Some may worry that portraying autism as hyper-male will trigger associations of people with autism as super-macho. Again, this would be a misconception, as machismo does not overlap with any exactness with the dimensions of systemizing and empathizing. Indeed, the negative connotations of being macho, such as aggression, are far from a good characterization of many people with autism spectrum conditions. Aggression is determined by many factors, and reduced empathy may be just one of them. And even then, reduced empathy does not invariably lead to aggression. It may not even lead to this in the majority of cases. Many people with autism spectrum conditions are gentle, kind people, who are struggling to fit in socially and care passionately about social justice: not the stereotype of a macho male at all.

Simon Baron-Cohen, The Essential Difference. Basic Books, 2003; pp. 184-185.

Davin said...

VERY masculine Aspie here. Physically and mentally. I am 21. (Physically, deep voice, very full beard, thick chest hair, balding, greying slightly). Far-right politically (conservative libertarian, radically so - tending towards reactionary bent). I am most definitely a systematiser, not an empathiser on this model. We must distinguish mature and immature masculinity; the former is just that, the latter incorporates machismo and so on, which is a false projection.