Over-specific perceptual learning in ASD

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder in which, in addition to social interaction and communication impairments, there are often sensory alterations. Much remains to be learned regarding the mechanisms governing sensory plasticity in ASD. Here, we do so using modulated levels of sensory adaptation. In non-ASD adults, repetitions are associated with specificity of visual learning and reduce sensory sensitivity due to adaptation. Individuals with ASD commonly require repetitive training for learning and the consequences of this are unknown. ASD adult individuals (N=11) and controls were trained with the same standard texture discrimination task (backward masked, randomized SOA) for 4 days (Harris, Gliksberg, Sagi; Curr. Biol.2012). Transfer was tested on day 5 by switching the target's location. The ability to learn at the new location was examined on days 6-8. In each group, half of the observers were trained with fixed target trials, termed standard training ('standard'), while the other half received added task-irrelevant trials ('dummy'), which are known to reduce adaptation and lead to transfer of learning in non–ASD subjects. Results showed that training with dummy trials facilitates learning and its transfer in ASD and non-ASD observers. Also, both ASD and non-ASD 'standard' observers showed negligible learning and specificity of learning. Most importantly, at the transfer location, unlike non–ASD observers who always learn at the new target location, ASD observers did not improve, reaching thresholds levels comparable to day1. Our results suggest that visual perceptual learning in ASD matches that of non-ASD observers. However, while non-ASD observers learn at the transfer location, ASD learning was over-specific and affected subsequent generalization. Reducing sensory adaptation positively impacts ASD observers, enabling enhanced learning and further generalization of learning. Together, these findings elucidate key properties of perceptual learning in ASD and offer guidance for future intervention.

Meeting abstract presented at VSS 2014