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dc.contributor.advisor Woldorff, Marty G en_US
dc.contributor.author Harris, Joseph Allen en_US
dc.date.accessioned 2012-05-25T20:11:46Z
dc.date.available 2014-05-15T04:30:05Z
dc.date.issued 2012 en_US
dc.identifier.uri http://hdl.handle.net/10161/5464
dc.description Dissertation en_US
dc.description.abstract <p>Any information represented in the brain, whether an individual is aware of it or not, holds the potential to affect behavior. The extent of visual perceptual processing that occurs in the absence of awareness is therefore a question of broad import and interest to the field of cognitive neuroscience. A useful approach for examining the extent and quality of visual processing that occurs in the absence of awareness is the dissociation paradigm. In this approach, experimenters track implicit measures of the visual process of interest across conditions of awareness modulated by visual presentation manipulations. Object-category discrimination by the visual system represents a relatively sophisticated level of representation that may or may not occur in the absence of awareness. Here, electrophysiological measures (scalp-recorded event-related potentials, or ERPs) of object-category discrimination by the brain (the face-specific N170 ERP component and the longer-latency face-specific negativity) were tracked across conditions of visual awareness as manipulated by multiple presentation paradigms (sandwich masking, object-substitution masking, the attentional blink, and motion-induced blindness). In addition, where possible, other related comparisons examining lower-level visual processes and higher-level attentional processes were employed to help delineate the specific level and mechanism by which awareness was disrupted in each case. The experiments implicated a unique set of mechanisms of reducing awareness for each method, while providing insight into the complex relationships between the various phases of visual processing in the human brain and awareness. Ultimately it was observed that neural indices of face-specific processing are differentially susceptible to disruption exerted by these various methods, and that there do in fact exist conditions in which awareness can be disrupted while leaving various facets and phases of face-specific processing intact. These findings help to establish object-category discrimination as a process that can occur in the absence of visual awareness, and contributes to our understanding of the neural factors that influence and determine behavior.</p> en_US
dc.subject Psychology en_US
dc.subject Neurosciences en_US
dc.subject Cognitive psychology en_US
dc.subject Awareness en_US
dc.subject Category en_US
dc.subject Electrophysiology en_US
dc.subject Faces en_US
dc.subject Masking en_US
dc.subject Vision en_US
dc.title Visual Object-Category Processing with and without Awareness en_US
dc.type Dissertation en_US
dc.department Psychology and Neuroscience en_US
duke.embargo.months 24 en_US

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