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Dissociable sensitivity and bias mechanisms mediate behavioral effects of exogenous attention

Sagar, Vishak and Sengupta, Ranit and Sridharan, Devarajan (2019) Dissociable sensitivity and bias mechanisms mediate behavioral effects of exogenous attention. In: SCIENTIFIC REPORTS, 9 .

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Official URL: https://dx.doi.org/10.1038/s41598-019-42759-w


Attention can be directed endogenously, based on task-relevant goals, or captured exogenously, by salient stimuli. While recent studies have shown that endogenous attention can facilitate behavior through dissociable sensitivity (sensory) and choice bias (decisional) mechanisms, it is unknown if exogenous attention also operates through dissociable sensitivity and bias mechanisms. We tested human participants on a multialternative change detection task with exogenous attention cues, which preceded or followed change events in close temporal proximity. Analyzing participants' behavior with a multidimensional signal detection model revealed clear dissociations between exogenous cueing effects on sensitivity and bias. While sensitivity was, overall, lower at the cued location compared to other locations, bias was highest at the cued location. With an appropriately designed post-cue control condition, we discovered that the attentional effect of exogenous pre-cueing was to enhance sensitivity proximal to the cue. In contrast, exogenous attention enhanced bias even for distal stimuli in the cued hemifield. Reaction time effects of exogenous cueing could be parsimoniously explained with a diffusion-decision model, in which drift rate was determined by independent contributions from sensitivity and bias at each location. The results suggest a mechanistic schema of how exogenous attention engages dissociable sensitivity and bias mechanisms to shape behavior.

Item Type: Journal Article
Additional Information: copyright for this article belongs to NATURE PUBLISHING GROUP
Department/Centre: Division of Biological Sciences > Centre for Neuroscience
Date Deposited: 23 Sep 2019 11:40
Last Modified: 23 Sep 2019 11:40
URI: http://eprints.iisc.ac.in/id/eprint/63635

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