The impact of autistic traits on emotional prosody and gesture perception: the behavioural and fMRI studies

Shim, Lee seul (2025) The impact of autistic traits on emotional prosody and gesture perception: the behavioural and fMRI studies. PhD thesis, University of Glasgow.

Abstract

This thesis combines behavioral and fMRI methods to investigate the neural and behavioral mechanisms of emotional processing in individuals with high-autistic traits (HAQ) compared with those with low-autistic traits (LAQ). The research focuses on the perception and processing of emotional information from prosody, gestures, and audiovisual displays of speech and gesture. It emphasized the study of specific brain regions and compensatory mechanisms that mediate the social communication difficulties commonly observed in those with high-autistic traits. The research involved several experimental studies, each aimed at a different aspect of emotional processing. Participants were divided into two groups based on their scores from the Autism Spectrum Quotient (AQ), which classified them as having high or low autistic traits. This grouping provided a structured approach toward understanding how trait severity impinges upon emotional processing.

In the prosody experiment, the participants were required to recognize emotions solely by the tone of voice. The results showed that the HAQ group showed reduced accuracy and slower response times, particularly in angry and happy emotional cues. The results of fMRI experiment also pointed out that HAQ participants showed less neural activation-indicative of a greater recruitment of cognitive control areas, such as the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC), suggesting more effortful processing to perform one or another type of processing related to emotional content compared with LAQ participants.

The experiment involving with the gesture showed participants with HAQ had an impaired recognition of emotions from body language, especially under congruence or incongruence conditions. Neuroimaging data revealed a greater reliance on brain regions involved in processing information of self-reference, namely the medial prefrontal cortex (mPFC) and insular cortex, implying compensatory strategies that do not fit the efficiency observed in LAQ group. This divergence in the neural pathways underlying the processing indicates the nature of the extra effort and special challenges taken by individuals with high autistic traits to interpret non-verbal social cues.

The audiovisual congruence study investigated how HAQ and LAQ groups integrate multisensory emotional signals. Behavioural results showed participants with HAQ to be significantly less accurate and slower to recognize emotions on trials presenting incongruent signals, such as mismatched body movements and vocal tones. Neuroimaging showed that HAQ individuals activated a wider number of neural structures when processing these emotionally complex situations, including prefrontal regions supporting cognitive control and conflict resolution. In contrast, results from LAQ participants indicated automated neural processing in typically responsible for perceptual integration sites such as the superior temporal gyrus (STG) and fusiform gyrus (FG), consistent with faster and more accurate emotional identification.

Specifically, the multisensory integration fMRI experiment investigated how visual and auditory emotional cues are integrated in individuals with HAQ. Results showed increased activation for the HAQ participants in areas of the brain that are involved in multisensory integration, including the posterior superior temporal gyrus (pSTG) and the ventrolateral prefrontal cortex (vlPFC.). These regions were more strongly activated in HAQ participants than in LAQ participants, in whom congruent emotional stimuli elicited more automatic processing. Further, the results suggest that HAQ individuals engage higher cognitive resources to attain the perception of emotion, emphasizing a basic dissimilarity in the manner of processing emotional information across modalities.

Overall, this thesis provides evidence that individuals with high-autistic traits rely on compensatory neural mechanisms due to difficulties in automatic sensory integration. The findings underpin the relevance of targeted interventions prioritizing enhancement in efficiency regarding emotional processing and reduction of cognitive load during the performance of social communication tasks. Limitations of research include a modest sample size and possible variation in the severity of autistic traits, which could affect generalizability. Larger and more diverse samples would be important to replicate these findings and investigate further the role of individual differences within the HAQ group.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: B Philosophy. Psychology. Religion > BF Psychology; R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Supervisor's Name: Pollick, Professor Frank E.
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85483
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 01 Oct 2025 15:42
• Last Modified: 01 Oct 2025 15:45
• Thesis DOI: 10.5525/gla.thesis.85483
• URI: https://theses.gla.ac.uk/id/eprint/85483