Visual information processing in the absence of awareness
Item
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Title
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Visual information processing in the absence of awareness
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Identifier
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d_2009_2013:da67cf39e087:11743
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identifier
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12331
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Creator
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Persuh, Marjan,
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Contributor
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Tony Ro
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Date
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2013
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology | Neurosciences | Cognitive psychology | awareness | consciousness | masking | priming | TMS | V1
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Abstract
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Several popular theories of consciousness propose that conscious representations entail deeper or more complex forms of information processing. We question this view and show that unconscious perception is more powerful than previously thought. In the first set of experiments we explore brightness perception, one of the most fundamental aspects of vision. We show, using a combination of metacontrast masking and priming, that the simultaneous brightness contrast (SBC) illusion occurs without awareness. These results demonstrate that our visual systems account for stimulus context in brightness perception for stimuli that we are unaware of. Our results further suggest that SBC occurs early during visual processing, likely within the initial feedforward sweep. We then extend these observations and demonstrate that activation of complex stimulus-response mappings also occurs unconsciously, when stimulus processing times are adequate. One of our key claims these results support is that some of the apparent differences between unconscious and conscious vision are due to differences in information processing times, as opposed to consciousness. We also show, using TMS, that unconscious shape priming requires primary visual cortex at specific temporal phases of processing. Because the later temporal phase of processing suppression has been proposed to interfere with feedback activity, our results further suggest that feedback is also essential for unconscious processing and may not necessarily be a signature of conscious vision. Together our results demonstrate that complex visual information can also be represented unconsciously, and suggest that conscious and unconscious vision use similar neural pathways and processes.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Psychology
