Visual Search: A Novel Psychophysics for Preattentive Vision

An important component of visual search is the preattentive guidance of attention towards a target item. The purpose of this investigation is to determine a tuning curve for these guidance mechanisms. The experiments utilize an oriented grating to mask preattentive guidance in a visual search for orientation. By systematically varying the orientation of the grating, we expected to determine the tuning curve for preattentive guidance mechanisms. The results, however, suggest that we found a tuning curve for early visual processing of unattended stimuli. Figure 1: Parallel search for a horizontal target among vertical distractors. The target seems to “pop out” of the display.