Okay; we’re up to our fourth cognitive theory of autism, a series of theories that attempt to explain the outward traits of autism by some difference in the brain or mind.

This theory is another one advanced by psychologist Simon Baron-Cohen, so it builds somewhat on his earlier ideas about theory of mind.  (He gives credit to much earlier researchers 60 years ago for first suggesting the “extreme male brain” idea, but it had not been considered for a long time.)  My feelings about the two theories are similar, meaning that I think Baron-Cohen has observed something real, but I’m not sure he has the whole picture right.  (And, to be fair, he doesn’t claim to– this is the way science works.  You create a scientific model based on observation and adjust it as new information comes in that works for or against it.)

Anyway, my material for this post largely comes from a 1999 paper by Baron-Cohen, accessible here in PDF format.  Baron-Cohen starts off by assessing the three cognitive theories of autism I’ve talked about on this blog, noting both strengths and weaknesses in each theory.  Then he cites a few findings from research:

  • Autism seems to be at least partly linked to genetics.  In the general population, autism seems to occur at a rate of somewhere between 0.05% and 0.1%.  But if a child is diagnosed with autism, there is a 3% chance that his or her sibling will also– a significantly higher number.  Also, among identical twins, there is a 60% chance that if one is diagnosed with autism, the other will be as well.  So while genetics may not be the only thing that determines whether you are autistic or not, there definitely seems to be a link.

    (I can personally attest that, while none of the other members of my family have been diagnosed with Asperger’s, we share a lot of the same personality traits.  Some of the material I read about the traits of Asperger’s made me say “This isn’t a disorder; this is my family!”)  🙂

  • Most of the people diagnosed with autism are male; the ratio is about 4 to 1.  If you only look at Asperger’s diagnoses (those with no delay in speech or cognitive development), the ratio is even more extreme, 9 to 1.

    It’s unclear why this is, though.  Some genetic conditions, like red-green colorblindness, much more commonly occur in males because the genes for them are on the X chromosome.  In order for a girl (with two X chromosomes) to be red-green colorblind, for example, she needs to receive the colorblindness gene from both her mother and her father.  A boy receives an X chromosome only from his mother (he gets a Y chromosome from his father), and if his one X chromosome has the colorblindness gene on it, he will be colorblind.  (I’m probably oversimplifying this example, but hopefully you understand what I mean.)

    But so far, at least, genetic research does not indicate that autism is linked to the X chromosome.  It seems to be tied to multiple genes on multiple chromosomes among the other 22 that humans have.  Researchers are trying to trace it to something they can identify (I think there was a recent article about a new finding in this area), but it’s really complicated.

Baron-Cohen then cites research noting that men and women tend to have different areas of cognitive strength.  Here are the strengths he lists for females:

  • Language tasks; girls tend to develop language skills faster than boys.
  • Tests of social judgment.
  • Measures of empathy and cooperation.
  • Perceptual speed; the ability to quickly identify matching items.
  • Ideational fluency; the example Baron-Cohen gives of this is quickly listing as many things as you can that are a specific color.
  • Fine motor coordination.
  • Mathematical calculation tests.
  • Pretend play in childhood.

Studies show that males tend to be weaker in the above areas but stronger in the following:

  • Mathematical reasoning; especially in areas like geometry, word problems, and higher-level math.
  • The embedded figure test; being able to find a shape in the middle of a jumble of distracting information.
  • Mentally rotating or folding an object and predicting what it will look like.
  • Some spatial skills.
  • Target-directed motor skills; guiding or intercepting projectiles.

If you know much about the traits of autism, a lot of these weaknesses and strengths probably sound pretty familiar.  Some of the descriptions of being excessively literal and concrete or socially clueless at times do sound similar to the kinds of things that people joke about as being a “guy thing” (and provide sitcom writers with plenty of material).  Could it be that an autistic brain is an “extreme” version of the male brain, with these weaknesses and strengths magnified even more?

Baron-Cohen suggests that this is precisely the case.  He cites a study finding that newborn girls were more likely to focus on faces and voices (social stimuli), while newborn boys were more likely to focus on a mobile (a non-social stimulus).  I guess they must have had the mobile right there in the delivery room for the experiment!

In fact, the differences between male and female brains are thought to date all the way back to about 8 weeks after conception.  In males, the hormone testosterone causes the baby’s brain to develop in a way that makes its two hemispheres less “connected” but more “focused.”  (My high school science teacher would sometimes refer to this as “brain damage,” which I didn’t find very funny, but I knew she was just joking.  The point was that God had designed men’s and women’s brains to work differently, and God himself said that was “good!”)

So overall, Baron-Cohen’s theory suggests that the autistic brain is an exaggerated version of the male brain.  He notes that this would help to explain why most diagnosed autistics are male, and that this is in keeping with the idea of an autism spectrum that blends smoothly into what is considered “normal.”

An anonymous commenter shared a link with me of a 2007 paper by Goldenfeld, Baron-Cohen, Wheelwright, Ashwin, and Chakrabarti (link leads to PDF file) that sought to evaluate the theory that the autistic brain is an “extreme male brain.”

For the purpose of this study, Goldenfeld et al. describe the “male brain” as being better at  systemizing and the “female brain” as being better at empathizing:

“Systemizing is the drive to understand the rules governing the behaviour of a system and the desire to construct systems that are lawful.  Systemizing allows one to predict and control such systems.  Empathizing is the drive to identify another person’s thoughts or emotions, and to respond to their mental states with an appropriate emotion.  Empathizing allows one to predict another person’s behaviour at a level that is accurate enough to facilitate social interaction.”

They stress that there is evidence that “these abilities compete, so that despite sex differences in cognitive style, there is no overall sex difference in cognitive ability.”

Goldenfeld et al. re-evaluate the data from a 2003 study that used questionnaires designed to measure a person’s “systemizing quotient (SQ)” and “empathizing quotient (EQ).”  These questionnaires were given to two groups:

  • A random sample of the population containing 114 males and 163 females.
  • Forty-seven people diagnosed with Asperger’s syndrome or high-functioning autism (33 males, 14 females)

The graph below shows their results:

goldenfeld-etal1

The group of people with Asperger’s are not differentiated by gender in the graph because the sample size wasn’t big enough for any difference to be significant.  The diagonal dividing lines are based on the difference between the systemizing and empathy quotients from the two questionnaires.

You can see that most (though not all) of the “control females” had an empathy quotient higher than their systemizing quotient.  Most (though not all) of the “control males” had a systemizing quotient higher than their empathy quotient.  And most (though not all) of the people with AS or high-functioning autism had a systemizing quotient much higher than their empathy quotient.

And so the thought is that something happens to make an autistic person’s brain an extreme version of the male brain– maybe a larger dose of testosterone while the baby is developing in the womb?

Anyway, I certainly think that this is an interesting theory (and I am amused by the idea that I can explain my quirks by saying “I’m just that manly”), but I don’t find this theory convincing without something better to back it up.  Baron-Cohen points out himself one area that the “extreme male brain” theory predicts autistics should be good at, but they typically aren’t:  lateral thinking.

But overall, I have more of a problem with the way that this study defines its own terms.  Is it really possible to boil down the differences between male and female brains to just one factor:  empathizing vs. systemizing?  There are many females who are good at systemizing, and many males who are good at empathizing.  (And to his credit, Baron-Cohen points out that the “gender” of one’s brain under his system does not have to match the person’s actual gender.)

And even these concepts themselves are quite complex– recall the post about empathy in which I wrote about how tricky it can be to define.  I think there is a great risk in this case of allowing your theory to influence the way you interpret your data.

The biggest problem I have with this theory is that it doesn’t have much to say about females with Asperger’s or autism.  I think they have been sadly overlooked, though hopefully that has begun to change.  And that’s an issue I want to talk about in another post.

Advertisements