title: Heterogeneity effects in visual search predicted from the group scanning model.
abstract: The group scanning model of feature integration theory (Treisman & Gormican, 1988) suggests that subjects search visual displays serially by groups, but process items within each group in parallel. The size of these groups is determined by the discriminability of the targets in the background of distractors. When the target is poorly discriminable, the size of the scanned group will be small, and search will be slow. The model predicts that group size will be smallest when targets of an intermediate value on a perceptual dimension are presented in a heterogeneous background of distractors that have higher and lower values on the same dimension. Experiment 1 demonstrates this effect. Experiment 2 controls for a possible confound of decision complexity in Experiment 1. For simple feature targets, the group scanning model provides a good account of the visual search process.
authors.affiliation: Department of Psychology, University of Alberta, Edmonton.
authors.forename: A D
authors.initials: AD
authors.lastname: Macquistan
mesh_terms: D000328:Adult; D001288:Attention; D003118:Color Perception; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008297:Male; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics; D011930:Reaction Time; D012858:Size Perception