Inflexible behavior, including rigidity in social situations and impaired learning, extends to sensory perception in adults with autism spectrum disorder (ASD), shows a study published this week in Nature Neuroscience. The study suggests that one of the techniques widely used for treatment and education in ASD, repetition, might actually decrease flexibility, and that reducing this repetition may improve the ability of people with ASD to transfer what is learned in one situation to other situations (generalization).
Dov Sagi and colleagues tested high-functioning adults with ASD and age- and gender-matched adults without ASD on a texture discrimination task in which the subjects had to determine the orientation of three lines on a screen (the target) that were embedded in a background of horizontal lines. Both subjects with ASD (10 adults) and control subjects (9 adults) learned the task, improving to a similar degree over the first four days. However, after the authors changed the position of the target lines, those with ASD performed substantially worse and relearned the task much more slowly than they had the first time. These results indicate a hampered ability to learn new conditions, or over-specificity, in the subjects with ASD.
By contrast, in a separate group of subjects with (10 adults) and without (10 adults) ASD, the authors found that adding some ‘dummy’ trials, during which the orientation of the target lines was forced to match the background, enabled those with ASD to learn the modified task at the same rate as the controlsubjects and generalize their learning when the target location was moved.
The repetition of the target in the initial test imposes a greater amount of sensory adaptation and results in a reduced representation of the target in early visual cortex, which likely leads to the reduced perceptual flexibility in people with ASD. Conversely, learning likely generalizes in the dummy test because the stimulus is more variable, consequently leading to less sensory adaptation.
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