Abstract
Multiple-target visual searches, where more than one target can be present in a search array, are subject to Subsequent Search Miss (SSM) errors: a decrease in second target detection after successful detection of the first target. While SSM errors have been known in radiology for over 50 years, their underlying cause remains elusive. The perceptual set account predicts that SSM errors are driven by target similarity, such that a second target is more likely to be missed if it is dissimilar to a previously found target. Biggs et al., (2015) demonstrated initial strong evidence for this account by exploring how different types of target similarity affect SSM errors. If a second target shared the identity, color, or category of a previously found target, observers made fewer SSM errors. However, target orientation was not investigated as a measure of similarity. Here, we investigated SSM errors in a multiple target search, with targets that appeared in the same or different orientation. Observers were asked to search for up to two targets: high- or low-salience target letter T's and L's, amongst low-salience pseudo T/L distractors. Four search items were independently rotated either 0°, 90°, 180°, or 270° and presented for 400ms equally centered around a fixation point. The results demonstrated an SSM effect with decreased low-salience target accuracy after a high-salience target was detected compared to single, low-salience, target accuracy. However, there was improved second target detection when both targets shared identity (i.e., both T's or both L's) and orientation, compared to when both targets were either different types (i.e., a T and an L) or different orientations (e.g., two T's of different orientations). These results provide novel evidence suggesting that SSM errors are impacted by the rotation of targets, providing further evidence for the perceptual set account.
Meeting abstract presented at VSS 2017