Memory under pressure: secondary-task effects on contextual cueing of visual search.

Repeated display configurations improve visual search. Recently, the question has arisen whether this contextual cueing effect (Chun & Jiang, 1998) is itself mediated by attention, both in terms of selectivity and processing resources deployed. While it is accepted that selective attention modulates contextual cueing (Jiang & Leung, 2005), there is an ongoing debate whether the cueing effect is affected by a secondary working memory (WM) task, specifically at which stage WM influences the cueing effect: the acquisition of configural associations (e.g., Travis, Mattingley, & Dux, 2013) versus the expression of learned associations (e.g., Manginelli, Langer, Klose, & Pollmann, 2013). The present study re-investigated this issue. Observers performed a visual search in combination with a spatial WM task. The latter was applied on either early or late search trials--so as to examine whether WM load hampers the acquisition of or retrieval from contextual memory. Additionally, the WM and search tasks were performed either temporally in parallel or in succession--so as to permit the effects of spatial WM load to be dissociated from those of executive load. The secondary WM task was found to affect cueing in late, but not early, experimental trials--though only when the search and WM tasks were performed in parallel. This pattern suggests that contextual cueing involves a spatial WM resource, with spatial WM providing a workspace linking the current search array with configural long-term memory; as a result, occupying this workspace by a secondary WM task hampers the expression of learned configural associations.