Don't distract the searcher: search performance for X-ray security screening images is reduced with the addition of a simple mental arithmetic task

Abstract

Recent studies have demonstrated the important role of working memory in conducting effective visual search. The present study examined the role that the central executive plays in visual search, which is believed to be necessary for high-level control and coordination in search, as well as storing task- and target-related information. Performance was compared across three tasks: a visual search task, a simple mental arithmetic task, and a combined task, in which mental arithmetic and visual search were performed simultaneously. Adding the mental arithmetic task to the visual search task increased search response time while decreasing search response accuracy. There was also a decrease in search response accuracy when participants were asked to search for more than one target simultaneously (the dual-target cost). However, the dual-target cost was not amplified when the mental arithmetic and visual search tasks were combined. The results replicate previous findings regarding the highly limited capacity of the central executive and its importance to search. At a practical level, these results suggest that search performance may be impaired in real-world visual search applications in which the observer is open to potential distractions from their environment, and that performance may be improved by imposing measures to either reduce or prevent such distractions.

Footnotes

 Supported by a grant from the UK Department for Transport and the Engineering and Physical Sciences Research Council.