Abstract
It is still unclear how working memory representations bias attentional selection in visual search and, specifically, how that bias affects top-down and/or bottom-up guidance in search. Researchers studying the influence of Working Memory (WM) load in visual search have found some discrepant data, sometimes showing a WM modulation (e.g. Oh & Kim, 2004) but sometimes finding lack of effects of passive working memory loads on search (e.g. Woodman, Vogel & Luck, 2001). However, recent data have shown that active working memory tasks do modulate visual search performance (Gil-Gómez de Liaño, Drew, Quirós & Wolfe, 2014). Does the effect of active WM tasks occur both for efficient and inefficient searches? We compared WM effects on a relatively inefficient search for a specific object among heterogeneous distractor objects and efficient search for a salient object among homogeneous distractors. As in Gil-Gómez de Liaño et al. (2014), we used two active WM tasks: active-span tasks and updating n-back tasks. In the first active-span task, participants had to count how many times WM items were repeated through several visual search trials. In the second task, information in WM had to be updated during the search task. The results show that active WM tasks only interfered with inefficient search tasks, not with efficient search. Moreover, inefficient searches, but not efficient ones, were sensitive to the degree of WM load: high WM loads in the active-span and updating tasks, produced higher RT x set size slopes in search (control-no load: 21 msec/item, high load-active span: 36 msec/item, high load-updating: 34 msec/item). No differences were found for slopes in efficient search (control-no load: 0.44 msec/item, high load-active span: 1.96 msec/item, high load-updating: 2.79 msec/item). The results suggest that active working memory loads specifically interfere with top-down guidance during visual search, but not under bottom-up guided search.
Meeting abstract presented at VSS 2015