title: Separation of low-level and high-level factors in complex tasks: visual search.
abstract: A method for assessing the role of low-level factors in complex tasks is described. The method, which involves comparing simple-discrimination performance and complex-task performance for the same stimuli, was used to assess the role of low-level factors in multiple-fixation visual search. In one experiment, the target and background were composed of line segments that differed in color, orientation, or both; in another, target and background were composed of filtered-noise textures that differed in spatial frequency, orientation, or both. Most of the variance in search time was found to be predictable from the discrimination data, suggesting that low-level factors often play a dominant role in limiting search performance. A signal-detection model is presented that demonstrates how current psychophysical models of visual discrimination might be generalized to obtain a theory that can predict search performance for a wide range of stimulus conditions.
authors.affiliation: Center for Vision and Image Sciences, University of Texas, Austin 78712, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Geisler
authors.forename: K L
authors.initials: KL
authors.lastname: Chou
mesh_terms: D001288:Attention; D004193:Discrimination Learning; D006801:Humans; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics; D011930:Reaction Time