Adaptation to Vocal Expressions and Phonemes Is Intact in Autism Spectrum Disorder

Abstract

Several recent studies have demonstrated reduced visual aftereffects, particularly to social stimuli, in autism spectrum disorder (ASD). This putative impairment of the adaptive mechanism in ASD has been put forward as a possible explanation for some of the core social problems experienced by children with ASD (e.g., facial emotion or identity recognition). We addressed this claim in children with ASD and typically developing children by using an established methodology and morphed auditory stimulus set for eliciting robust aftereffects to vocal expressions and phonemes. Although children with ASD were significantly worse at categorizing the vocal expressions compared with the control stimuli (phoneme categorization), aftereffect sizes in both tasks were identical in the two participant groups. Our finding suggests that the adaptation mechanism is not universally impaired in ASD and is therefore not an explanation for the social perception difficulties in ASD.