Can that IQ be Right? Autism and IQ

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More and more often I am advocating for children on the autism spectrum who are achieving at or above grade level, but whose IQ scores show them to have below average or even mentally deficient intelligence levels. The IQ score is supposed to represent a person’s ability to learn so, how could it be that a child could be learning so well but be mentally retarded?

The answer is that it can’t be; it makes no sense. New research shows that the IQ scores of children on the autism spectrum may not be accurate reflections of their innate intellectual potential. While in the past many psychologists have believed that the vast majority of children with autism had below normal intelligence, recent scientific studies have questioned it.

As it turns out, the standard IQ tests (the WISC-IV and the Stanford-Binet), which school psychologists and others often use, do not tap the true cognitive ability of many children on the autistic spectrum. According to the highly respected National Research Council, in order for an autistic child to perform to their ability on a standard IQ test, they must be able to quickly respond to verbal questions and have well developed motor skills. But if your disability by definition prevents you from doing that with the test administrator (as autism often does), you may not be able to demonstrate your true intelligence.

Some people might say “Well, if you can’t engage interpersonally, listen and express yourself, then you’re just not very smart, and you deserve the low IQ score you received.” But, the truth is that IQ tests are supposed to measure a person’s intellectual potential, and not their ability to communicate what they know to a stranger. Other people might say “Well, who cares if my child’s IQ score is inaccurately low — it might actually help me get disability benefits.”

The reason why as an advocate I care is because schools use the IQ score to place children. Often children with below average or mentally deficient IQ scores are placed in classrooms in which students are not expected to meet grade level standards (i.e. Sunshine State standards) and teachers are not held accountable under the No Child Left Behind Act for student progress. Once a child has been in that type of classroom for a few years, it becomes extremely difficult to catch up to their mainstream peers.

What Can You Do About It?

I like to give my readers practical solutions in this newsletter, and not just talk about theory. I have a few recommendations depending upon your specific circumstances:


  • If your child on the autism spectrum has never had an IQ test, I do not see why you need to run out and get one. A child can be diagnosed with and treated for autism without having a traditional IQ test. And schools can legally make decisions about classroom placement without knowing your child’s IQ.
  • If your child’s public school evaluates him or her for special education services, the school psychologist will often want to do an IQ test. If your child is on the spectrum and you think they might not do so well on a standard IQ test, you can either:
    • Refuse to consent to any IQ test — when you sign the parental consent form authorizing the public school to evaluate your child, you could write-in that you do not agree to any IQ test. Be polite and simply say something like you “don’t believe in the IQ test –never have.” You wouldn’t be the first one to have major problems with IQ testing — it’s falling out of favor in many quarters of the field of education, including in Gifted Education;
    • Refuse to consent to standard IQ tests (the WISC-IV and the Stanford Binet), but authorize the school to use other reputable IQ tests which may be more valid assessments of intellectual ability with autistic kids. Three of those other IQ tests are: i) the Raven Progressive Matrices test; ii) the Leiter International Performance Scale (your child needs to be able to communicate by gesturing for this test); and iii) the Kaufman Assessment Battery for Children. Understand that it is not clear whether or not a parent has the legal right to tell the school district which IQ test you want administered. However, you can try this approach and see if it sticks.
  • If the school insists on performing an IQ test, show them this recent “Newsweek” article which talks about the problems with giving standard IQ tests to autistic children and hope that they take heed.
  • If the public school has recently evaluated your child for special education services, there will be a meeting during which the results of the evaluation are discussed. If the school psychologist administered an IQ test and you believe that the results may not be accurate, you have the legal right to request that the school district pay for a private evaluation called an “Independent Educational Evaluation.” For more information on your right to an “IEE,” look it up on
  • If you want or need to pay for a privately administered IQ test, this article by Gary J. Heffner, M.A. has some good tips on how to best ensure a valid test administration. Some parents get a private IQ test done if they feel pretty confident that the school psychologist won’t have the time and the resources to do a good enough job with their child, yet someone they trust has recommended that one be done.

I know this is a very complicated issue and I hope I’ve shed some light on it. If you have any questions, or want to share your personal experiences with the IQ test and the school system, please send me an email or call.


UPDATE  Article first published 1/7/2007. 

In a 2009 study*, children with autism and typically-developing children were given two IQ tests: the Wechsler Intelligence Scale for Children (a widely used IQ test involving a great deal of language) and the Raven’s Progressive Matrices (a measure of nonverbal, “fluid intelligence”).
Results of the study revealed: Typically-developing children scored similarly on both tests, but results of two tests were significantly different for children with autism.    None of the children with autism in the study scored above average on the WISC, but 33% percent did so on the Raven’s Progressive Matrices.  33% percent of the children with autism scored in the range of mental retardation on the WISC, but only 5% scored in this range on the Raven’s Progressive Matrices.
Judith Migoya, Psy.D, of Pediatric Psychology Associates, advises that parents request that psychologist use the Ravens or another test of intelligence which is less language-laden called the Leiter-R.  These tests can be administered in addition to the WISC or on their own.  Dr. Migoya also suggests that psychologists employ some of the following testing accommodations when administering assessments:  Presenting one item at a time to reduce stimuli; Using a visual schedule to reduce anxiety; and Providing positive reinforcement to help students to finish an exam which may not appear relevant to them.

*Isabelle Soulieres, Ph.D., post-doctoral fellow, Harvard University, Boston; Laurent Mottron, M.D., Ph.D., professor of psychiatry, University of Montreal; Brenda Smith Myles, Ph.D., chief of programs, Autism Society of America; June 2009, Human Brain Mapping.