Prosodic Speech Production and Perception Differences Comparing Populations with Varying Levels of Autistic Traits

Abstract

Autism spectrum disorder (ASD) represents a group of developmental disabilities associated with impairments in social, communicative, and imaginative abilities. Speech impairments associated with ASD can be explained by differences in cognitive processing styles relative to neurotypicals. Previous studies found that individual differences in cognitive processing influence one’s production and perception of prosody. For example, Stewart et al. (2018) found that higher levels of autistic character traits indicated by one’s Autism Spectrum Quotient (AQ) score (Baron-Cohen et al., 2001) correlated significantly with one’s ability to discriminate pitch and time, but no significant correlation between auditory discrimination thresholds for intensity. Additionally, Turnbull (2015; 2019) observed shorter overall word and vowel durations during a task which required participants with varying AQ scores to speak for the benefit of a listener with a hearing impairment. The present study examined whether prosodic cue-trading in production and perception differs when comparing populations with varying levels of autistic traits, as indicated by their AQ score differences. Furthermore, the study investigated whether these differences exist on a continuum, or rather are categorical, with respect to participants’ level of autistic character traits. To achieve this, we analyzed individual variability patterns in 18 participants’ speech production and perception. Results from the perception task showed that participants displayed a significant enhanced perception of pitch and intensity, but not duration, when completing a task where participants listened to sentences manipulating the prosodic parameters f0, intensity, duration. Results from the production task where participants read sentences designed to elicit background, broad, and narrow focus found no significant effect of AQ across any of the acoustic parameters measured, although the results for f0 are near the 5% significance level for the f0 condition, suggesting that participants with higher AQ scores may produce lower f0 ranges, and thus, less prosodic variability compared to low AQ participants.