Dawson: There are very different approaches to measuring intelligence. One is a battery of tests, as in Wechsler Scales of Intelligence. You are trying to get at general abilities by using an array of different specific tests, so you’re trying to get at something latent. These are specific abilities, but through those, you come up with some kind of latent general ability that we call intelligence or full-scale intelligence.
Or you can take one test with one format that is sufficiently complex and difficult that it gets at the same thing, just with one test. That would be Raven’s Progressive Matrices, a test that has been extremely influential in the entire intelligence literature.
Cowen: And which test do autistics tend to do better on and why?
Dawson: Autistics do better on Raven, quite a bit better. In some individuals, the discrepancy is spectacular – it’s a lot.
You’ll have an individual in the savant literature who really cannot perform other tests, would be judged as very intellectually disabled on other tests, effectively can’t perform a receptive language test, much less produce language. And [their] score is very high on Raven – I mean, better than most of the typical population, all but 1 percent or 2 percent. And again, he had to have the opportunity to do that for us to find that out.
And tragically, yet unsurprisingly:
Dawson: There was a paper in 2004, and it was one of the first ones I actually looked at in an editing capacity after it was accepted provisionally, and it did find, but very tentatively, that autistics were possibly performing better on Raven than these other tests. The interpretation in the paper was that Raven wasn’t a good test for autistics. It must overestimate autistic intelligence.
... First off, I had to look at what Raven was and how it was being interpreted in the autism literature, which is that when autistics performed well, it was almost denigrated as a test: “This is just visual-spatial abilities,” and so on. And you look in the intelligence literature, and you have this test that is really central in defining human intelligence that is very important and requires all these abilities that autistics supposedly don’t have.
And I thought, “Well, isn’t this worth pursuing?” And it did take a lot of persuasion to go in that direction, to sort of question the commonplace and typical.
And this is typical of the autism literature. Autistics perform well on the test? There must be something wrong with the test.