The Deficiency Of Attentional Bias To Emotional Prosody In Autism Spectrum Disorders: Perceptual Overload Or Diminished Motivation?

Attentional bias refers that comparing with neutral stimuli,emotional stimuli usually get prior attention and process.About the attentional bias to emotions in visual channel,previous studies reported that people with autism spectrum disorders(ASD)had atypical attention patterns of emotional faces and pictures with absent first attention to emotional stimuli and preference to neutral materials.However,little was known about the attentional bias to auditory emotions in ASD.Emotional expression also depends on the changes of acoustic cues in speech,such as pitch,intensity and duration,which constitute emotional prosody.To investigate the generality of attentional bias to cross-model emotions in ASD,we extended the experimental materials to emotional prosody and focused on the impact of novel emotional prosody on the behavioral data and pupil size as a marker of the attentional bias to emotional prosody.So far,based on the perceptual load theory,some studies demonstrated the deficiency of attentional bias to emotions in ASD was because the perceptual load of the main task was too high for them so the emotions were not processed.However,more recent studies were rooted in social motivation theory of ASD and believed the deficiency is mainly from the diminished social motivation when processing emotions.Therefore,it is necessary to do more exploration about the underlying reasons for the deficiency of attentional bias to emotions in ASD.We presented an oddball paradigm including two types of novel emotional prosody within a sequence of repeated standard neutral prosody to 15 people with ASD and 17 typical developing(TD)people,while the participants were required to complete a main task.Results showed that:(1)in experiment 1,the reaction times of main task under the novel emotional prosody conditions were longer than the standard neutral prosody in TD.And the reaction times and error rates had no significant differences across three types of emotional prosody in ASD;(2)in experiment 2,angry and happy novel prosody elicited a strong pupil dilation response in TD only,but not in ASD.(3)in experiment 3,whether in high or low perceptual load,reaction times and error rates of the main task as well as accuracies of emotional prosody detection task between two groups have no significant differences.And the respense was influenced by the novel emotional prosody under the attentional condition in ASD.The results strongly suggested that(1)the attentional bias to emotional prosody was deficient in ASD,which was consistent with the results from visual channels.(2)the deficiency was mainly from the diminished social motivation in this group when processing emotions,which supported the social motivation theory of ASD.