423 research outputs found

    Spatial attention increases performance but not subjective confidence in a discrimination task

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    Selective attention to a target yields faster and more accurate responses. Faster response times, in turn, are usually associated with increased subjective confidence. Could the decrease in reaction time in the presence of attention therefore simply reflect a shift toward more confident responses? We here addressed the extent to which attention modulates accuracy, processing speed, and confidence independently. To probe the effect of spatial attention on performance, we used two attentional manipulations of a visual orientation discrimination task. We demonstrate that spatial attention significantly increases accuracy, whereas subjective confidence measures reveal overconfidence in non-attended stimuli. At constant confidence levels, reaction times showed a significant decrease (by 15–49%, corresponding to 100–250 ms). This dissociation of objective performance and subjective confidence suggests that attention and awareness, as measured by confidence, are distinct, albeit related, phenomena

    Spatial displacement, but not temporal asynchrony, destroys figural binding

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    What are the elementary features that the brain uses to bind spatially distinct parts in a visual scene into an unitary percept of an “object”? The Gestalt psychologists emphasized the extent to which motion, colour, luminance or spatial arrangement contribute towards object formation. Little is known about the role of timeper se, rather than motion, in constituting an object. In particular, does the visibility or saliency of an object change if the various parts making up the object are not presented simultaneously? Using a simple experimental design, we show that very small spatial displacements can significantly influence the saliency of an object while large temporal asynchrony has no significant effect

    Modeling Investigation of the Underground Dam on Samui Island, Southern Thailand

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    Water Resources Planning and Managemen

    Under- versus Overestimation of Aquifer Hydraulic Conductivity from Slug Tests

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    Groundwater Hydrology, Irrigatio
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