Autism and Intelligence: The Facts

Tuesday, 07 December 2010

Autism and Intelligence: The Facts

WordPress has a nifty feature which tracks the search terms people use which lead them to this blog. One of the most common queries is some variation on, “Can autistic people be smart?” or from another angle, “Can autistics be retarded?”. Contrary to popular opinion, the answer to both questions is yes.

Autism is classified as a Pervasive Developmental Disorder because it affects multiple areas of development, including motor skills, communication, and sensation. But one area where it has no direct influence is intelligence.

I use the word “direct” because autism will affect tested intelligence, but will not affect how “smart” an individual is. Traditional IQ testing is not possible with many individuals with autism because of communication barriers which prevent proper gauging. Even those whose communication skills will not affect testing still have various other factors to contend with, including the lighting of the room (autism and fluorescent lighting is a notoriously bad combination), physical ability to complete desired activities (poor fine motor skills will reduce testable capability in areas like putting together a puzzle, organizing tangrams to match a pattern, and doing pen-and-paper calculations and brainstorming), and other sensory issues which may interfere with testing. Autistics are thus at an automatic disadvantage when it comes to traditional IQ testing.

However, there are fortunately other ways to measure or at least infer intelligence. For example, I was able to witness the administration of one form of adapted IQ test while I was working at the library. The boy being tested was supplied with a toy to keep him occupied (in this case a marble race track), and while he played the tester asked him a series of questions which only required one-word answers. Questions ranged from: Name something yellow you can eat to Name a tool you can cut with when you don’t have a scissor to Name the President to If I took half of your dozen marbles, how many would you be left with, and thus tested daily living skills, vocabulary, knowledge, math skills, adapting to problems, etc. The child viewed the experience as more of a game, and the tester was provided a great deal of useful information that could be combined to yield, at the very least, a likely IQ range.

Traditional IQ testing of the autistic population originally lead to the conclusion that the majority of autistics had mild to moderate retardation (an IQ score between 30 and 70), with a few having exceptionally higher scores, a few exceptionally lower, and many of the remainder falling between borderline-retardation and average IQ (100).

But recent examinations using alternative testing strategies has revealed a distribution that is quite different, one which is notable because of how closely it resembles the distribution for the Neurotypical (non-autistic, non-learning disabled) population. Less than a third test in the retardation range (<70), less than a third test in the gifted range (>130), and the majority fall around the normed average of 100. As procedures and accommodations are improve so that testing for autistics can accurately reflect IQ, this distribution will likely come even closer to approximating the curve for the general population.

Take-home message: Traditional IQ tests do not supply accurate reflections of an autistic individual’s intelligence. The true IQ distribution for autistics is likely very similar to that of the general population, with some having very high scores, some very low, and the majority falling in the average range.

Edited to add: Until further investigation has been completed (and by further research I mean, at least a decade’s worth, if not more), it is not possible to know the true distribution of IQ among the autistic population. The trend in research, however, suggests that the distribution is far closer to that of the general population than previously thought.

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