title: Searching while loaded: Visual working memory does not interfere with hybrid search efficiency but hybrid search uses working memory capacity.
abstract: In "hybrid search" tasks, such as finding items on a grocery list, one must search the scene for targets while also searching the list in memory. How is the representation of a visual item compared with the representations of items in the memory set? Predominant theories would propose a role for visual working memory (VWM) either as the site of the comparison or as a conduit between visual and memory systems. In seven experiments, we loaded VWM in different ways and found little or no effect on hybrid search performance. However, the presence of a hybrid search task did reduce the measured capacity of VWM by a constant amount regardless of the size of the memory or visual sets. These data are broadly consistent with an account in which VWM must dedicate a fixed amount of its capacity to passing visual representations to long-term memory for comparison to the items in the memory set. The data cast doubt on models in which the search template resides in VWM or where memory set item representations are moved from LTM through VWM to earlier areas for comparison to visual items.
authors.affiliation: University of Utah, Salt Lake City, UT, USA. trafton.drew@psych.utah.edu.
authors.forename: Trafton
authors.initials: T
authors.lastname: Drew
authors.affiliation: Goethe Universitat Frankfurt, Frankfurt, Germany.
authors.forename: Sage E P
authors.initials: SE
authors.lastname: Boettcher
authors.affiliation: Brigham & Women's Hospital, Boston, MA, USA.|Harvard Medical School, Boston, MA, USA.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Wolfe
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D057567:Memory, Long-Term / Q000502:physiology*; D008570:Memory, Short-Term / Q000502:physiology*; D011930:Reaction Time; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology*
keywords: Dual-task performance; Visual search; Working memory