Interesting autism quiz here.

The thing that bothered me about it is how arbitrary the questions are.  Unlike IQ tests, where there’s a somewhat objective way of knowing whether an item is good or not (g factor loading) there doesn’t seem to be much of a science behind autism research.

The quiz also seems to assume autism is a continuous variable like height, weight, or IQ, such that everyone in the World can be ranked in order from least autistic to most autistic, but perhaps autism doesn’t work that way.  Maybe it’s a discrete variable, like Down syndrome: you either have an extra chromosome or you don’t.  Ok, Down syndrome’s not that black or white, but close.

Suppose we had no blood test for Down syndrome, but instead it was like autism and we had to rely on questionnaires that had questions like:

Are you short?

Do you have trouble learning?

Do you have slanted eyes?

Do you have a large tongue?

Are you stocky?

If such a test had enough items, the results would form a nice bell curve, and we could easily deceive ourselves into thinking that as many as 20% of humanity had a mild form of Down syndrome.  I fear something like that might be the case when certain commenters on this blog go around labeling anyone who’s a bit nerdy or socially awkward as autistic.

Of course autism might be the extreme end of the normal spectrum as I’ve argued in the past but we must be careful we don’t fall for the  reification fallacy:  Assuming that whatever receives a name or can be scored by a quiz, must have an objective reality.

Of course Stephen Jay Gould famously argued (incorrectly in my opinion) that IQ was an example of the reification error.