Abstract
Attentional templates are representations of target features in working memory (WM). Although two attentional templates can guide visual search in dual-target search, search efficiency is reduced compared with one attentional template in single-target search. According to the resource hypothesis of visual search (Huynh Cong & Kerzel, 2021), the reason is that two attentional templates receive an equal share of resources in WM, which is smaller than the amount of WM resources allocated to one attentional template. To assess the value of this hypothesis, we asked participants to always memorize two colors, but the use of the corresponding WM representations varied. In the blocked condition, the two colors were either maintained as attentional templates for dual-target search, or as simple WM representations for recall only. In the mixed condition, one color was maintained as an attentional template for single-target search and the other as a simple WM representation for recall only. We found that reaction times (RTs) were delayed and recall precision reduced with two attentional templates in the blocked condition compared with one attentional template in the mixed condition, indicating that search efficiency and WM resources similarly decreased in dual- compared with single-target search. Moreover, the attentional template was always recalled much more precisely than the simple WM representation in the mixed condition, even when we substantially reduced the frequency of visual search. Consistent with the existence of an “active” state in WM, resources were strongly biased toward the attentional template in single-target search. In dual-target search, however, resources were balanced between two attentional templates, as with two simple WM representations. Therefore, the allocation of WM resources goes beyond the traditional dichotomy between “active” and “accessory” WM states and explains how attentional templates can guide visual search with variable efficiency.