Schizotypy and facial emotion processing

The ability to accurately interpret facial emotion is crucial to social being and our capacity to correctly interpret threat-related expressions has obvious adaptive value. Healthy individuals appear to process facial emotions rapidly, accurately and effortlessly, while individuals with schizophrenia often present with marked impairment in emotion processing. The hypothesis of continuity between schizophrenia and normal behaviour suggests that the signs and symptoms of the disorder also occur to varying, lesser degrees in the general population. This thesis presents a series of studies that explore the limits of facial emotion processing in healthy individuals, and its relationship with schizotypal personality traits. The first paper describes a set of three studies that use eye tracking techniques to explore the limits of rapid emotion processing. It is shown that we can quickly orient attention towards emotional faces even when the faces are task-irrelevant, presented for very brief intervals, and located well into peripheral vision. The remaining studies explore whether high schizotypes have similarities to individuals with schizophrenia in the way that they process facial emotion. High schizotypes were significantly less accurate at discriminating facial emotions and significantly more likely to misperceive neutral faces as angry, offering support for continuum models of visual hallucinatory experiences. A further study revealed that high relative to low schizoptypes feel as though they are exposed to angry faces for longer. It is argued that this experience itself may serve to maintain hypervigilance to social threat. Finally, laterality biases during face perception were explored. Contrary to the predictions of continuum models of schizophrenia, high schizotypes had an increased left side / right hemisphere bias for face processing. In summary, the thesis offers partial support for the hypothesis of continuity between the impairments in emotion discrimination observed in individuals with schizophrenia, and normal, healthy variation in facial emotion processing

No experimental evidence for emotion-specific gaze cueing in a threat context

We examined the utility of a gaze cueing paradigm to examine sensitivity to differences among negatively valenced expressions. Participants judged target stimuli (dangerous or safe), the location of which was cued by the gaze direction of a central face. Dawel et\ua0al. reported that gaze cueing effects (faster response times on valid vs. invalid trials) were larger when the central face displayed fear than when it displayed happiness. Our aim was to determine whether this effect was specific to fear, to all threat-related expressions (fear, anger), or to all negatively valenced expressions (fear, anger, sadness, disgust) with the aim of using this protocol to study the development of implicit discrimination of negatively valenced expressions. Across five experiments in which we varied the number of models (1 vs. 4), the number of expressions (2 vs. 5), and the country of residence of participants (Canada vs. Australia) we found no evidence that the magnitude of gaze cueing effects is modulated by expression. We discuss our failure to replicate in the context of the broader literature