Individual differences in recogn-eye-zing faces: Behavioural and neural underpinnings of face recognition in neurotypical and autistic adults

Abstract

Attention to another’s eyes and face recognition are necessary building blocks for efficient social communication. Neurotypical adults show an attentional bias for the eye region and strong face recognition performance. In contrast, adults with an autism spectrum disorder (ASD) often have pervasive difficulties looking at the eyes and recognizing others. These behavioural tendencies have led researchers to propose the eye avoidance and indifference theories of face recognition: implicating disruptions in eye sensitivity as a potential source of face recognition difficulties, although a direct link has yet to be established at the individual level. Holistic integration also plays a key role in neurotypical face recognition, although the temporal neurodynamics of autistic holistic integration remain unclear. Addressing this clinically relevant gap in the literature and acknowledging the within-group heterogeneity reported for both autistic and neurotypical adults, this dissertation presents four empirical studies evaluating feature saliency during face perception and its relationship with face recognition accuracy in adults with and without an ASD. Chapter 2 presents one of the first evaluations establishing direct associations between fixations to internal facial features during face encoding and recognition accuracy (d′) across incidental and intentional task demands. Results demonstrate incidental recognition accuracy is positively associated with left eye and nasion fixation patterns but is negatively impacted by increased fixations to the nose. Intentional recognition accuracy, on the other hand, negatively correlates with fixations directed towards non-core features and sub-clinical autistic traits. Chapter 3 then extends this research into a clinical ASD population and neurotypical control adults, evaluating face recognition performance from a neurodiversity perspective. Despite between-group analyses revealing autistic adults spend less time looking at faces during encoding, neurotypical and autistic adults’ eye movements do not differ in their fixation patterns towards internal features nor in their recognition accuracy scores. Within-group analyses for adults with an ASD reveal a negative association between autism symptomology and intentional face recognition accuracy. To clarify the temporal neurodynamics of early face perception in autism, two ERP experiments were completed by a subset of participants from Chapter 3. N170 peak amplitudes and latencies were measured in response to upright/inverted faces and cars, isolated eye regions, and isolated mouths (Chapter 4) and in response to intact faces with fixation enforced to the left eye, right eye, nasion, nose, or mouth (Chapter 5). Consistent with neurotypical patterns, autistic adults demonstrate preserved markers of eye sensitivity and holistic integration at the N170 level when fixation is enforced. Collectively, this research signifies the importance of the eyes and nasion in supporting neurotypical and autistic face recognition accuracy and emphasizes the importance of accounting for individual differences from a neurodiversity perspective in social cognition research. Considerations for monitoring visual attention to faces and moving towards more individualized methods in neuroimaging studies are also discussed. This research has important clinical implications for the advancement and assessment of face recognition and social cognition abilities in ASD.