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Rachel Denison, William Adler, Marisa Carrasco, Wei Ji Ma; Accounting for attention in perceptual decisions and confidence. Journal of Vision 2017;17(10):386. doi: 10.1167/17.10.386.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To make optimal perceptual decisions, observers must take into account the uncertainty inherent in their sensory representations. Humans take into account sensory uncertainty caused by stimulus factors such as low contrast. However, it is not known whether humans take into account sensory uncertainty caused by internal factors such as low attention. Here we asked whether humans adjust their perceptual decisions and confidence reports to account for attention-dependent uncertainty. Methods: Twelve observers performed an orientation categorization task, in which the two categories had the same mean orientation but different standard deviations, and reported both categorization (category 1 or 2) and confidence (4-point scale) on each trial. In this task, unlike a traditional left vs. right orientation discrimination, the optimal choice boundaries depend on orientation uncertainty. We manipulated endogenous (voluntary) covert spatial attention trial-by-trial using a central precue pointing to one of four possible stimulus locations (valid and invalid precues) or to all locations (neutral precue). Four stimuli appeared briefly on each trial, and a response cue indicated which stimulus should be reported. We used generative modeling of the experimental data and model comparison to determine the influence of attention on decision and confidence boundaries. Results: Attentional cueing affected performance accuracy—highest for valid, intermediate for neutral, lowest for invalid—verifying that the attentional manipulation of orientation uncertainty was successful. Decision and confidence boundaries shifted under different levels of attention in a way indistinguishable from optimal. The Fixed model, in which observers do not adjust for attention-dependent uncertainty, fit the data poorly. The Bayesian model and two heuristic models, in which observers adjust boundaries according to parametric decision rules, performed similarly, and substantially better than the Fixed model. Conclusion: Perceptual decision-making responds flexibly to uncertainty related to attention, an internal state. This flexibility should improve perceptual decisions in everyday vision.
Meeting abstract presented at VSS 2017
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