Abstract
Inefficient search is the process of locating a target among distractors whose features are highly similar to those of the target. Such search requires a serial process, in which one must foveate items one-by-one until the target is found. As such, mean response time increases for each additional distractor in the display. It has been shown that inefficient search uses visuospatial working memory (VWM). When an inefficient search was completed while participants were holding information in VWM, the search slope was greater than when the search task was run in isolation (Woodman & Luck, 2004). We therefore hypothesized that individual differences in VWM capacity might predict individual differences in search slopes. Toward that end, we developed four tasks to measure working memory capacity. In the Corsi blocks task, we asked participants to remember, and subsequently identify in order, sets of spatial locations presented serially within a grid. Set size increased across blocks. We also used three change detection tasks. In the first task, we asked participants to detect changes between pairs of displays containing twelve spatial locations arrayed within a grid. In the second task, we asked participants to detect changes between pairs of displays containing four dots arrayed along an invisible circle. The third task was a test of non-spatial working memory, which served as a control condition. We asked participants to detect changes between a probed color and a set of four colors presented previously. Finally, participants performed an inefficient search task with two difficulty conditions (difficult and very difficult) and two set sizes (5 and 8). We used individual differences in working memory capacity to predict individual differences in inefficient search slopes. The findings are discussed in terms of the different underlying memory constructs that contribute to performing inefficient search.