News The latest developments in autism research.
Profiles Portraits of scientists who are making a mark on autism research.
Toolbox Emerging tools and techniques that may advance autism research.
Spotted A roundup of autism papers and media mentions you may have missed.
Opinion Conversations on the science of autism research.
Viewpoint Expert opinions on trends and controversies in autism research.
Columnists Dispatches from experts on various facets of autism.
Crosstalk Debates and conversations about timely topics in autism.
Reviews Exploring the intersection of autism and the arts.
Q&A Conversations with experts about noteworthy topics in autism.
Deep Dive In-depth analysis of important topics in autism.
Special Reports Curated collections of articles on special topics in autism.
Webinars Presentations by leading experts on their latest research.
News

Study of recurring beeps supports ‘magical world’ theory of autism

by  /  12 November 2017
Regular rhythm: Testing children’s brain responses to repeated sounds hints at how well they can predict events.

westphalia / iStock

Children with autism do not predict repeating sights and sounds, even after experiencing them dozens of times over a few minutes.

The findings support the ‘magical world’ hypothesis, in which an inability to detect patterns and predict what happens next underlies some of autism’s core features. If social behavior seems random, for instance, it would be hard to know what to do in social situations. And if sensory stimuli always come as a surprise, a person would naturally be more sensitive to them.

Researchers presented the unpublished findings yesterday at the 2017 Society for Neuroscience annual meeting in Washington, D.C.

The tendency to tune out a repeated stimulus is known as habituation. It’s a mechanism for filtering out ‘background noise’ (or the equivalent in other sensory realms) so that a person can pay attention to important information.

Some studies have suggested that habituation is impaired in people with autism. Most of these studies have tracked responses to a novel sight or sound after the same one has been presented several times.

In the new study, researchers did not insert a new stimulus, but instead simply repeated the same one at a regular, metronomic pace. They recorded brain activity in 10 children with autism and 21 typical children aged 7 to 12 years as the children listened to a series of 300 identical beeping sounds that occurred once every second.

Tuning out:

In the typical children, a spike of brain activity associated with each beep dropped as the children heard more beeps, suggesting that they habituated to the noise.

In many of the children with autism, however, the spike did not diminish, and in some, it intensified over the course of the experiment. As a group, children with autism showed significantly less habituation than the controls, the researchers found.

“They can’t disengage with the stimulus,” says Wasifa Jamal, a postdoctoral researcher in Pawan Sinha’s laboratory at the Massachusetts Institute of Technology, who presented the work. “They can’t tune it out.”

The researchers then showed the two groups of children a checkerboard pattern that flashed on a screen once a second for 300 seconds. Again, they found that the spike of brain activity in response to the pattern gets smaller with repetition in controls — but not in children with autism.

This shows that impairments in habituation affect multiple senses in children with autism, Jamal says. “It’s not domain-specific.”

Children with severe autism features show greater impairments in habituation to the repeated beeps than do those with mild features. (The researchers found no relationship between autism severity and responses to the checkerboard flash.)

Unpredictable world:

The magical world hypothesis is not the only one that is consistent with impaired habituation in autism, says Scott Murray, associate professor of psychology at the University of Washington in Seattle, who was not involved in the work. But, he says, “it totally resonates with me.”

Murray has unpublished brain imaging data that similarly show reduced habituation to a regular, repeated stimulus in people with autism. His study also indicates that the difference in brain activity between people with autism and controls disappears when a stimulus is unpredictable.

The Sinha team is continuing to test the magical world theory, also known as the ‘predictive impairment in autism’ hypothesis, Jamal says. The researchers are studying habituation to touch. They are also using a variety of ways to measure brain activity and other physiological responses. And they are tracking children’s responses to real-world stimuli such as videos or approaching balls.

For more reports from the 2017 Society for Neuroscience annual meeting, please click here.

Corrections

A previous version of the article said the children listened to a series of 50 identical beeping sounds rather than 300.


  • Kal

    This is an incredibly broad interpretation of a narrow finding. Just because the brain continues to react to a repeating pattern doesn’t mean that the person can’t recognize the pattern or predict it. And it’s even more far fetched to conclude that they think the entire world is magical. A more reasonable conclusion would be simply that autistic subjects were more sensitive to a repeated stimulus than controls.

    Imagine if the experiment was done with a more jarring stimulus such as being hit or hearing an extremely loud sound. I’m guessing the finding might be that even a neurotypical person continues to show a brain spike to such a repeating stimulus. Yet we wouldn’t use this to conclude that the subject just can’t reason enough to predict that the unpleasant stimulus will happen yet again!

    Also, describing this as an impairment in habituation is ableist and presumes that it’s better to ignore repeating stimuli – yet that’s not ideal in all situations (think of a security guard who has to watch the same screen all day). If the result were the other way around, I bet the article would say that autistic people show an impairment in the ability to pay attention to repeated stimuli.

    • Claire Cameron

      Response from Wasifa Jamal:

      Thank you for your thoughtful comments regarding this work. We agree with your point that reduced habituation does not necessarily imply an inability to predict how a sequence is going to unfold. Indeed, as you suggest, a very salient stimulus may lead to sensitization. Interestingly, in exploring whether sensory acuity in autism might be heightened relative to typical development (which may then lead to enhanced saliency of stimuli), several studies indicate that there is no systematic difference between ASD and NT participant groups. We have therefore had to consider alternative explanations for the oft observed sensory hypersensitivities in autism. The prediction framework provides one possible account, though certainly not the only one. Our current efforts focus on rigorously testing this possibility by investigating predictive abilities in a variety of settings. Since habituation is an unconscious process, we intend to further explore whether unconscious or conscious predictions lead to increased habituation or anticipatory neural responses to repetitive stimulus sequences, as well as the degree to which stimulus predictability influences habituation.

      We also appreciate your point about the term ‘impairment’ as carrying a value judgment. We shall try to use more neutral terms like ‘differences’, but any specific suggestions you might have are very welcome!

      • Kal

        I really appreciate your reply. It is very encouraging to see that scientists are listening to the autism community.

        Certainly the term “differences” would be a better one to use rather than “impairments.” I’m also bothered myself by the name of the “magical world” theory, as it conveys the image of someone lost in a fantasy land and unable to grasp cause and effect. I can tell that autistic kids can understand cause and effect just from watching how carefully my autistic toddler figured out how to stir cookie dough without flipping over the bowl. And of course the writings of autistic adults reveal that these are not people who are unable to make predictions or notice patterns. Whatever differences there may be in predictive ability, they must be subtle ones and they need a popular name that is not derogatory and that does not portray autistic people as incapable of reason in the eyes of the general public. Thank you again for listening!

  • endolex

    I disagree with this interpretation. To me, it certainly doesn’t feel like a lack of habituation, but an abundance of attempted habituation. If anything, I often try too hard to make “too much” sense of everything that is happening around me.

    For any observation, an explanation that requires “many steps” comes as readily to me as the immediate one that more neurotypical ppl might offer – depending on how much pre-existing knowledge I have on the topic. Filtering out the less likely from the probably true is a chore, and exhausting – especially in social situations where a lot of learning and internal statistics is involved.

    So it’s “magical world” only in the sense that I see ‘more’ (as in: ‘more potential connections that might or might not exist’), but certainly not in an “anything goes, because everything is just random” meaning.

close

Log in to your Spectrum Wiki account

Email Address:

Password:


close

Request your Spectrum Wiki account

Spectrum Wiki is a community of researchers affiliated with an academic or research institutions. To be considered for participation, please fill out this form and a member of our team will respond to your request.

Name:

Email Address:

Title and Lab:

Area of Expertise:

Comments: