| Summary: | 博士 === 國立臺灣大學 === 心理學研究所 === 98 === Visual attention studies have suggested two bases of selection—location-based and object-based. Location-based attention denotes that locations in the visual field are selected; object-based attention denotes that objects are selected. Location- and object-based attention are not mutually exclusive; they can influence the allocation of attention simultaneously. Over the last two decades, many studies have focused on the boundary conditions of each basis of selection; however, little is known about the underlying mechanisms of each. This thesis describes a series of five studies examining the mechanisms of location-based and object-based attention.
Section I includes three studies manipulating visibility of stimuli with respect to location (chapter 2), object (chapter 3), and target (chapter 4) and distinct functions (action/object recognition), brain pathways (dorsal/ventral pathway), and underlying mechanisms (signal enhancement/noise exclusion) of location-based and object-based attention are differentiated accordingly. Section II includes two studies manipulating high-level factors—working memory (chapter 5) and expectations (chapter 6)—and demonstrated the high-level cognitive factors also affect location-based attention and object-based attention differently.
Taken together, results from these five studies show that location-based and object-based attention (1) are influenced by consciousness in different ways, (2) have different underlying mechanisms, (3) involve different kinds of working memory, and (4) rely on different aspects of cue validity. These findings challenge and shed new insights into current theories of attention. The consciousness-dependent hypothesis and the optimization hypothesis are proposed to explain the novel findings reported in this thesis.
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