Abstract:

Emotional attention bias refers that emotional stimuli usually get priority of attention over the neutral stimuli, which has been frequently replicated in normal participants. However, previous studies reported that teenagers with autism spectrum disorders (ASD) had atypical attention patterns of processing emotional faces and pictures, that is, their first attention was located at the neutral stimuli instead of the emotional stimuli. According to the perceptual load theory, some studies demonstrated the deficiency of attention bias to emotions in the teenagers with ASD was due to the perceptual load of the main task was too high for them, so that they can’t process the emotion. Till now, little has been known about the ASD teenagers’ attention in processing auditory emotional stimuli, although emotional expression also actually depends on the changes of acoustic cues in the speech prosody. To testify the generality of attention bias to cross-model emotions in the teenagers with ASD, we extended the experimental materials to emotional prosody. In present study, 14 teenagers with ASD and 17 typical developing (TD) people were recruited in two experiments. The participants were required to complete a main task while the emotional prosody voices were presented as the deviated task-irrelevant stimuli. In Experiment 1, the participants were instructed to ignore sounds and to classify the pictures. In Experiment 2, we adopted a dual-task paradigm, which required participants to respond to the target letters first and then to point whether they hear the novel emotional prosody. And in experiment 2, we also manipulated the level of perceptual load through changing the similarity between the letters in virtual round.

Results showed that: (1) Reaction time of ASD subjects were longer than TD subjects under any different emotions rhyme categories. (2) Whether in high or low perceptual load, reaction times and error rates of the main task as well as accuracy of emotional prosody detection task between two groups of participants have no significant differences. In providing notice indicating conditions, even in a high perceptual load level, ASD subjects of emotional rhythm detection capability and error rates are similar to TD subjects, but for emotional rhythm react time with neutral rhythm no difference. These findings revealed that ASD have the similar attention processing level with TD in attention conditions.

The results of two studies strongly suggested that the attention bias to emotional prosody was deficient in the teenagers with ASD, which was consistent with the results from visual channels and the teenagers with ASD have defect on emotional attention bias in auditory channel, main showed low perception efficiency on emotional rhythm perception.

Key words: autism spectrum disorders, teenagers, emotional prosody, attention bias, perceptual load