It likely won’t come as a shock to those acquainted with people on the autism spectrum. But until a group of scientists at Vanderbilt University conducted a study on how perceptions of visual and auditory events differ in those with autism and those without it, no one could say exactly what the differences were.
For their study, the research team, led by Mark Wallace, director of the Vanderbilt Brain Institute, matched up 32 children ages six to 18, pairing them in “virtually every possible way including IQ”—except that half the children had high-functioning autism diagnoses and the other half weren’t autistic. The scientists then led the children through a sequence of tasks, mostly on computer, that included various audiovisual events, like flashes and beeps and a hammer hitting a nail, and asked them whether the sound and the visual event happened contemporaneously or separately. The study showed that the autistic kids had wider “temporal binding windows,” which caused their brains to have trouble integrating sounds and visual events occurring within a certain timeframe. According to Stephen Camarata, co-author of the study, “It is like they are watching a foreign movie that was badly dubbed; the auditory and visual signals do not match in their brains.” (Vanderbilt has posted a video demonstrating the effect here.) The result can be social and behavioral difficulties.
As Wallace says, “One of the classic pictures of children with autism is they have their hands over their ears. We believe that one reason for this may be that they are trying to compensate for their changes in sensory function by simply looking at one sense at a time”—a strategy “to minimize the confusion between the senses.” Wallace is hopeful that because the brain is highly plastic, ways to narrow the “window” and improve sensory integration will be found—and could also be applicable to treatment of such disabilities as dyslexia and schizophrenia.
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