Visual search for singleton feature targets across dimensions: Stimulus- and expectancy-driven effects in dimensional weighting.
Four pop-out search experiments investigated whether dimension-based visual attention is top-down modulable. Observers searched for singleton feature targets defined, variably across trials, by a color or an orientation difference to nontargets. Observers were precued to the most probable target-defining dimension (e.g., by the word color) or feature (red) on a given trial. Results revealed expedited reaction times (RTs) for valid-dimension targets relative to neutral-cue conditions, and slowed RTs for invalid-dimension targets. Cue information as to precise target feature yielded some extra effect only for color targets. The dimensional cuing significantly reduced, but did not abolish, the dimension-specific influence of the previous target on detection of the current target (same-dimension RT < different-dimension RT). These findings confirm that top-down dimensional set modulates stimulus-driven dimension processes in the detection of pop-out signals. ((c) 2003 APA, all rights reserved)
Ludwig-Maximillians-U Munchen, Dept Psychologie, Munich, Germany. mueller@psy.uni-muenchen.de
Hermann J
HJ
Muller
Brit
B
Reimann
Joseph
J
Krummenacher
D000328:Adult; D001288:Attention / Q000502:physiology*; D003116:Color; D003463:Cues; D004192:Discrimination, Psychological; D005260:Female; D005364:Field Dependence-Independence; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D010364:Pattern Recognition, Visual; D010470:Perceptual Masking / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time; D014796:Visual Perception / Q000502:physiology*; D014836:Volition / Q000502:physiology