How does autism affect intelligence levels?

Chantal Sicile-Kira
Mental Retardation & Developmental Disabilities Specialist

In recent years, it has become widely recognized that autism has nothing to do with intelligence.

Recent studies show that the IQ scores of children on the autism spectrum may not be accurate reflections of their innate intellectual potential. Often those who are performing at grade level or above in school have IQ scores that show them to have below average or even mentally deficient intelligence levels. But these IQ tests do not tap the true cognitive ability of many children on the autistic spectrum. They tell us more about their communication and motor difficulties.

Children and teens with autism are impacted by sensory processing challenges, and this can affect test results. For example, a student with autism may not be able to respond in a room with bright fluorescent lights. As well, a person with Asperger’s Syndrome may do well in answering test questions, but not necessarily realize how the information relates to her personally. It is important to remember that just because a person cannot talk does not mean they have nothing to say, or that they do not understand what they are hearing in class or reading in books. Conversely, just because a person sits in a class and can repeat to you what was said does not mean he has internalized and learned it.

*Asperger syndrome, or Asperger's, is a term that is no longer used as a formal diagnosis. In current diagnostic criteria, the syndrome is included under the diagnosis of autism spectrum disorders.

According to the CDC (2007) 58 % of females and 42% of males on the autism spectrum also have an intellectual disability. Individuals with ASDs have highly variable learning profiles and a great deal of scatter across cognitive domains. When there is significant scatter across cognitive domains, the full scale IQ score may not represent the child’s overall cognitive functioning and is simply an average of highly discrepant skills. In addition nonverbal IQ tends to be more stable than verbal IQ in children with full diagnosis of autism. 

William Stillman
Health Education Specialist

This is one of the great myths and stereotypes about autism that require dispelling. In years past, autism and mental retardation were believed to be synonymous. But thanks to emerging research by Meredyth Goldberg Edelson and Morton Ann Gernbacher, we are learning that individuals with autism are intellectually competent. Thus it would seem that autism is not an issue of mental inferiority at all; it is an issue of disconnection between the body being able to authentically articulate what the brain is telling it by coordinating the production of intelligible speech or written or typed communication or being able to regulate fine and gross motor skills.

Contrast the autistic experience with that of an individual with cerebral palsy to better understand. On the surface, the person with CP appears to have significant limitations which may include little or no speech and lack of motor coordination to ambulate, eat, dress, or bathe; however, their intelligence is wholly intact!

When in doubt, your mantra should always be "presume intellect." This means that we should communicate to and with the person with autism at their chronological age level with total belief that they're "in there," alert, responsive, listening and learning!

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.