Schizophrenia (SCZ) is associated with robust social deficits, which have been shown to precede illness onset and predict functional outcome. As a result, social functioning is an important developmental domain affected by SCZ, which likely has a downstream negative impact on other functional abilities, such as interpersonal relationships and vocational capacity. Patients with SCZ also demonstrate significant visual perceptual deficits; however, a remaining question is whether basic impairment in visual processing gives rise to the deficits observed in social perception. In this context, previous research has shown that biological motion contains relevant social information, such as emotional states and intention, which is easily interpreted by healthy observers. Given that biological motion perception is an important source of social information, and that patients with SCZ have known visual perceptual impairment including motion processing deficits, it is possible that poor biological motion perception meaningfully impacts social perception among individuals with SCZ. While previous studies have documented preliminary evidence of biological motion processing deficits in this population, there is a current lack of understanding regarding the basic visual perceptual mechanisms that may underpin this impairment, including the importance of basic visual motion processing with respect to biological motion. Moreover, the ability of individuals with SCZ to extract relevant social information from biological motion, and its relationship with social perception more generally, have yet to be investigated. Thus, the specific aims guiding the current thesis were to examine whether basic visual motion processes may give rise to biological motion deficits and to examine the ability of individuals with SCZ to extract
social information, in the form of emotion, from biological motion. Several experimental tasks were used to examine these aims. Overall, the results from this thesis confirm that individuals with SCZ have difficulty perceiving biological motion; however, this deficit was not specific to biological motion, but instead reflected more widespread visual motion processing deficits, including impairment in global coherent motion perception. Additionally, results from this thesis suggest that individuals with SCZ demonstrated disproportionate difficulty extracting social cues, in the form of emotion, from biological motion, and that this deficit was related to perceiving unambiguous expressions of emotion. In contrast, the discrimination of more subtle or ambiguous emotion was relatively preserved. Moreover, impairment in biological motion processing was found to be unrelated to social perceptual abilities among individuals with SCZ. These experiments provide interesting suggestions regarding clinical approaches to treatment and remediation, although further research is needed to fully understand the brain- behaviour mechanisms underlying SCZ-related deficits in biological motion processing. / Dissertation / Doctor of Philosophy (PhD) / As people navigate though day-to-day life, they encounter many objects in the world that move, such as other people. Research has shown that humans are adept at discriminating human movement and accurate in discerning the emotional states of other people based on this movement. These observations have lead researchers to speculate that, because biological motion is both easy to discriminate and emotionally informative, it plays an essential role in social processing among humans. Research has shown that individuals with Schizophrenia have difficulty understanding social environmental cues, such as the emotions of others. As such, this thesis aims to determine first, whether people with Schizophrenia have difficulty identifying human motion, and second, if they are able to identify emotions embedded within human motion. This thesis will help researchers understand and explain deficits in social perception among people with Schizophrenia.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18228 |
| Date | 11 1900 |
| Creators | Spencer, Justine Margret Yau |
| Contributors | Christensen, Bruce, Sekuler, Allison, Psychology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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