Autism spectrum disorders alter the perception of the environment. Patients overestimate the odds of the improbable happening.
Imagine opening your sock drawer and finding a pineapple. The find is surprising. Now add to the situation a toddler playing in the bedroom. The presence of a fruit in clothes is immediately a little less surprising, because the child increases the likelihood of unexpected events.
His actions are detrimental to the proper understanding of the link between the presence of a sock drawer, and its probable container, that is to say socks. This is how researchers from the University College of London (UCL) have imagined the difficulties of understanding experienced by people with an autism spectrum disorder (ASD) when faced with their surroundings.
External instability
An experiment they conducted on fifty people, half of whom suffered from ASD, showed that autistic people overestimated the inconstancy of their environment. For them, no need for the presence of a child to upset the odds. This could explain part of their symptoms, especially concerning their intolerance to change.
“The idea of a link between the construction of different visual expectations in autistic people and their social difficulties is an intriguing possibility,” explains Geraint Rees, professor of cognitive neurology at UCL, and one of the authors of the study published in Nature Neuroscience.
A clear association
The British researchers proposed an experiment consisting in teaching a classic pattern of events: participants heard a sound – either low-pitched or high-pitched – followed by an image linked to the sound. For example, a high sound was followed by a picture of a house, and a low sound by a face. To create an unexpected event, it was enough to present a face after a high-pitched sound.
To gauge their reaction to this change, they observed the participants’ behavior and the dilation of their pupils. When unexpected events occurred, people with ASD reacted less than others. And the more severe the symptoms, the weaker the reaction.
A beginning of explanation
“When uncertainty invades our own beliefs, for example when circumstances are volatile, we rely more on our senses than on our forecasts,” explains Dr. Rebecca Lawson, neuroscientist and lead author of the study. If people with autism face this inconstancy more often, it could explain their propensity for sensory overload, their perceptual functioning and their insensitivity to context. »
The UCL findings could at least shed some light on how people with ASD perceive the world around them.
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