The Role of Working Memory in Dual-Target Visual Search.

Visual search (VS) for multiple targets is especially error prone. One of these errors is called subsequent search misses (SSM) and represents a decrease in accuracy at detecting a second target after a first target has been found. One of the possible explanations of SSM errors is working memory (WM) resource depletion. Three experiments investigated the role of WM in SSM errors using a dual task paradigm. The first experiment investigated the role of object WM using a classical color change detection task. In the second and the third experiments, a modified change detection task was applied, using shape as the relevant feature. The results of our study revealed no effect of additional WM task on second target detection in dual-target VS. To this end, SSM errors are not related to WM resource depletion. On the contrary, WM task performance was violated by dual-target VS as compared to single-target VS, when the targets in VS task were defined by the same feature used in the WM task.