Color-selective attention need not be mediated by spatial attention.
It is well-established that attention can select stimuli for preferential processing on the basis of non-spatial features such as color, orientation, or direction of motion. Evidence is mixed, however, as to whether feature-selective attention acts by increasing the signal strength of to-be-attended features irrespective of their spatial locations or whether it acts by guiding the spotlight of spatial attention to locations containing the relevant feature. To address this question, we designed a task in which feature-selective attention could not be mediated by spatial selection. Participants observed a display of intermingled dots of two colors, which rapidly and unpredictably changed positions, with the task of detecting brief intervals of reduced luminance of 20% of the dots of one or the other color. Both behavioral indices and electrophysiological measures of steady-state visual evoked potentials showed selectively enhanced processing of the attended-color items. The results demonstrate that feature-selective attention produces a sensory gain enhancement at early levels of the visual cortex that occurs without mediation by spatial attention.
Andersen
Søren K
SK
Psychologie & Methodenlehre, Institut für Psychologie I, Universität Leipzig, Leipzig, Germany. andersen@rz.uni-leipzig.de
Müller
Matthias M
MM
Hillyard
Steven A
SA
D000328:Adult; D001288:Attention / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D003463:Cues; D005074:Evoked Potentials, Visual; D005260:Female; D006706:Homeostasis; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D013028:Space Perception / Q000502:physiology / Q000528:radiation effects*; D014793:Visual Cortex / Q000502:physiology; D055815:Young Adult