Neural evidence for reduced automaticity in processing emotional prosody among men with high levels of autistic traits

Abstract

This study aimed to examine individual differences in the integration of emotional prosody when processing semantic meaning in speech among men with high and low levels of autistic traits, as measured by the Autism Spectrum Quotient (AQ). The behavioral and neural responses of high- and low-AQ men during semantic valence judgment were compared. The stimuli were positive or negative words spoken with either happy or sad prosody; in other words, the prosody was either congruous or incongruous to the valence of meaning. Participants were required to judge the (positive vs. negative) valence of word meaning as accurately and as quickly as possible while ignoring emotional prosody. Behavioral results showed that high-AQ men responded significantly more slowly than low-AQ men in all stimulus conditions, indicating lower automaticity in processing emotional speech. Neural data revealed that low-AQ men (but not high-AQ men) had significantly increased N200 and N400 amplitudes for incongruous (compared to congruous) stimuli spoken with happy prosody. Our findings supported our hypotheses that high levels of autistic traits are associated with reduced behavioral automaticity and less differential neural resources allocated to processing emotional speech stimuli with different cognitive demands.