The accurate integration of audio-visual emotion cues is critical for social interactions and requires efficient processing of facial cues. Gaze behavior of typically developing young adults was measured via eye-tracking during the perception of dynamic audio-visual emotion (DAVE) stimuli. Participants were able to identify basic emotions (angry, fearful, happy, neutral) and determine the congruence of facial expression and prosody. Perception of incongruent videos resulted in increased reaction times and emotion identification consistent with the facial expression. Participants consistently demonstrated a featural processing approach across all tasks, with a significant preference for the eyes. Evidence of hemispheric lateralization was indicated by preferential fixation to the left (happy, angry) or right eye (fearful). Fixation patterns differed according to the facially expressed emotion, with the pattern that emerged during fearful movies supporting the significance of automatic threat processing. Finally, fixation pattern during the perception of incongruent movies varied according to task instructions.

<p>Schizophrenia is a psychiatric disorder characterized by social dysfunction. People with schizophrenia misinterpret social information and it is suggested that this difficulty may result from visual processing deficits. As faces are one of the most important sources of social information it is hypothesized that people suffering from the disorder have impairments in the visual face processing system. It is unclear which mechanism of the face processing system is impaired but two types of deficits are most often proposed: a deficit in face perception in general (i.e., processing of facial features as such) and a deficit in facial emotion processing (i.e., recognition of emotional facial expressions). Due to the contradictory evidence from behavioural, electrophysiological as well as neuroimaging studies offering support for the involvement of one or the other deficit in schizophrenia it is early to make any conclusive statements as to the nature and level of impairment. Further studies are needed for a better understanding of the key mechanism and abnormalities underlying social dysfunction in schizophrenia.</p>

Individuals with autism spectrum disorders (ASD) use atypical approaches when processing facial stimuli. The first purpose of this research was to investigate face processing abilities in adults with ASD using several tasks, to compare patterns of interference between static identity and expression processing in adults with ASD and typical adults, and to investigate whether the introduction of dynamic cues caused members of one or both groups to shift from a global to a more local processing strategy. The second purpose was to compare the gaze behaviour of groups of participants as they viewed static and dynamic single- and multiple-character scenes. I tested 16 adults with ASD and 16 sex-, age-, and IQ-matched typical controls. In Study 1, participants completed a task designed to assess processing speed, another to measure visual processing bias, and two tasks involving static and dynamic face stimuli -- an identity-matching task and a Garner selective attention task. Adults with ASD were less sensitive to facial identity, and, unlike typical controls, showed negligible interference between identity and expression processing when judging both static and moving faces. In Study 2, participants viewed scenes while their gaze behaviour was recorded. Overall, participants with ASD showed fewer and shorter fixations on faces compared to their peers. Additionally, whereas the introduction of motion and increased social complexity of the scenes affected the gaze behaviour of typical adults, only the latter manipulation affected adults with ASD. My findings emphasize the importance of using dynamic displays when studying typical and atypical face processing mechanisms. / October 2015

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Individuals with autism spectrum disorder (ASD) have difficulties in many areas of social cognition including face perception. Decades of research examining face processing abilities in ASD populations have yielded equivocal results. The current thesis includes a series of experiments intended to clarify the nature of the face processing deficits seen in ASD. In Study 1 I examined norm-based coding of facial identity in adults with ASD. I measured identity aftereffects in adults with and without ASD and found no significant group differences. In Study 2 I examined simple (Experiment 1) and opposing (Experiment 2) figural aftereffects for male and female faces and found no significant group differences as adults with ASD. In Study 3 I examined perceptual strategies employed by adults with ASD when processing emotional facial expressions and found that adults with ASD employ a rule-based strategy. Finally, in Study 4 I examined what drives face processing deficits in adults with ASD; deficits in processing emotional information in faces or a deficit in processing socially complex information in faces. I found that adults with ASD had a deficit in discriminating basic and complex emotional facial expressions, suggesting that emotion-perception demands are associated with poor face processing in ASD. The results of the studies demonstrate that adult with ASD show typical perceptual mechanisms underlying face perception, use an atypical perceptual strategies when processing facial expressions, and have a specific deficit in processing emotional expressions. / Thesis / Doctor of Philosophy (PhD)

During the first year of life, infants’ capacities for face processing are shaped by experience with faces in their environment; a process known as perceptual narrowing. Perceptual narrowing has been found to lead to a decline in infants’ abilities to identify and differentiate faces of other races. In the current study, it is hypothesized that this decline may also lead to differential processing of emotion information in own- versus other-race faces. In the current research, we recorded electrophysiological data (Event-related potential; ERP) from 5- and 9-month-old infants while they were presented with paired emotion non-verbal sounds and faces. ERPs in response to the sounds suggest that both 5- and 9-month old infants differentiate happy and sad sounds. The pattern of results, however, is different across ages. ERPs in response to the faces suggest that whereas 5-month-olds exhibit differential responses to happy and sad faces for both the N290 and P400 components, 9-month-olds did not differentiate happy and sad faces. Nine-month old infants did exhibit a great P400 in response to own- relative to other-race faces. These results suggest that although both 5- and 9-month olds differentiate happy and sad emotional sounds, their processing of emotion faces differs.

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Yes / Principal component analysis (PCA) is an elegant mechanism that reduces the dimensionality of a dataset to bring out patterns of interest in it. The preprocessing of facial images for efficient face recognition is considered to be one of the epitomes among PCA applications. In this paper, we introduce a novel modification to the method of PCA whereby we propose to utilise the inherent averaging ability of the discrete Biharmonic operator as a preprocessing step. We refer to this mechanism as the BiPCA. Interestingly, by applying the Biharmonic operator to images, we can generate new images of reduced size while keeping the inherent features in them intact. The resulting images of lower dimensionality can significantly reduce the computational complexities while preserving the features of interest. Here, we have chosen the standard face recognition as an example to demonstrate the capacity of our proposed BiPCA method. Experiments were carried out on three publicly available datasets, namely the ORL, Face95 and Face96. The results we have obtained demonstrate that the BiPCA outperforms the traditional PCA. In fact, our experiments do suggest that, when it comes to face recognition, the BiPCA method has at least 25% improvement in the average percentage error rate.

Yes / It has been proposed that mentalising involves retrodicting as well as predicting behaviour, by inferring previous mental states of a target. This study investigated whether retrodiction is impaired in individuals with Autism Spectrum Disorders (ASD). Participants watched videos of real people reacting to the researcher behaving in one of four possible ways. Their task was to decide which of these four “scenarios” each person responded to. Participants’ eye movements were recorded. Participants with ASD were poorer than comparison participants at identifying the scenario to which people in the videos were responding. There were no group differences in time spent looking at the eyes or mouth. The findings imply those with ASD are impaired in using mentalising skills for retrodiction.