How does feature-based attention affect visual processing?
Five experiments are reported from which it is concluded that attending on the basis of a stimulus feature (e.g., red) does not directly affect the sensory quality of stimuli that possess that feature. Feature-based attention was manipulated in a visual search task by providing information about the probability that the target would possess a given feature (e.g., "The target has a 1.0 probability of being red when present.") Feature-based attention failed to aid performance under "data-limited" conditions (i.e., those under which performance was primarily affected by the quality of the stimulus) but did affect performance under conditions that were not data limited (Experiments 1-3). If attending to a feature had affected the sensory quality of stimuli, performance should have been aided under all conditions. Experiments 4 and 5 provided converging support for this conclusion.
Department of Psychology, Johns Hopkins University. cmm15@psu.edu
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D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D006801:Humans; D011930:Reaction Time; D014796:Visual Perception / Q000502:physiology*