Masking in Central Visual Field Under a Variety of Temporal and Spatial Configurations

dc.contributor.advisorWilson, Hugh R.
dc.creatorDaar, Marwan Abdallah
dc.date.accessioned2018-03-01T14:04:32Z
dc.date.available2018-03-01T14:04:32Z
dc.date.copyright2017-08-01
dc.date.issued2018-03-01
dc.date.updated2018-03-01T14:04:32Z
dc.degree.disciplinePsychology(Functional Area: Brain, Behaviour & Cognitive Science
dc.degree.levelDoctoral
dc.degree.namePhD - Doctor of Philosophy
dc.description.abstractFor over a century, visual maskingwhere one stimulus reduces the visibility of another stimulushas been used as a powerful tool to explore the visual system. Two major forms have emerged: backward masking and common onset masking. These two forms, which are characterized by the temporal properties of the stimuli, are often used to probe different underlying masking mechanisms, and the two forms typically employ a unique set of spatial characteristics of the mask. This clustering of stimulus properties makes it challenging to assess the effect of each stimulus property by itself. This dissertation describes an attempt to isolate the effects of these properties. In the first set of experiments various masking schedules are tested, including backward, common onset, and variations between, while keeping the spatial properties of the stimuli constant. In the second set of experiments four-dot common onset masking is explored in detail, and in one of the experiments, a single masking schedule is tested while varying the spatial properties of the mask. Across all experiments, target stimuli are presented foveally. A computational model is developed to account for data across both sets of experiments. Three important findings emerge. First, masking can be successfully obtained in central visual field using a variety of stimulus properties. Second, there is compelling evidence that persisting traces of these stimuli play an important role in masking. Third, there is strong evidence of both spatially local and global masking effects.
dc.identifier.urihttp://hdl.handle.net/10315/34358
dc.language.isoen
dc.rightsAuthor owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.
dc.subjectNeurosciences
dc.subject.keywordsVisual masking
dc.subject.keywordsObject substitution masking
dc.subject.keywordsOSM
dc.subject.keywordsMetacontrast
dc.subject.keywordsBackward masking
dc.subject.keywordsComputational neuroscience
dc.subject.keywordsPsychophysics
dc.titleMasking in Central Visual Field Under a Variety of Temporal and Spatial Configurations
dc.typeElectronic Thesis or Dissertation

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