The Locus of Visual Search's Interference on Visual Working Memory

Visual attention and visual working memory (VWM) are interacting systems. Most research has been directed toward how a retained VWM load can influence visual search behavior. However, the relationship between the two is bidirectional. When performing a visual search while maintaining a VWM load, decreases in change detection accuracy are often seen. Woodman and Luck (2010) argued that this interference was due to the onset of the search display leading to disruption. The current work attempts to identify the exact component of visual search that leads to interference with VWM. Potentially interference could be due to an attentional component of the task or a procedural artifact of the dual-task paradigm. Over five experiments, different attentional tasks were completed in the retention period of a difficult change detection task. Memory interference was measured as accuracy decrements in these conditions compared to trials where no attentional task was completed. Over the five experiments, one factor was highlighted as a sufficient cause for interference: the addition of nontarget items in the attentional task. Procedural artifacts were ruled out as potential sources of interference including: response bindings, eye movements, nontarget variance, spatial shifts of attention, perceptual load, and the time it took to complete the attentional task. It is proposed that interference arises from the attentional selective process of choosing the target item out of the nontargets.