Citation

Menneer T, Barrett DJK, Phillips L, Donnelly N, Cave KR. Appl. Cogn. Psychol. 2007; 21(7): 915-932.

Affiliation

Centre for Visual Cognition, School of Psychology, University of Southampton, UK; Department of Psychology, University of Massachusetts, USA

Copyright

(Copyright © 2007, John Wiley and Sons)

DOI

10.1002/acp.1305

PMID

unavailable

Abstract

The cost of searching for two visual targets simultaneously was compared against two separate single-target searches using exposure time and accuracy measures within a staircase procedure. Dual-target search for all stimuli (colour, shape and orientation) exhibited a loss of accuracy for one target. For orientation and shape, this dual-target cost in accuracy was extreme, with chance-level performance on one target. For colour, dual-target search exhibited an additional cost in search time, with search requiring a longer exposure than the summed time required for two single-target searches. An additional search-time cost was also found for orientation targets when irrelevant colour variation was added to the display. In conclusion, dual-target search for dissimilar targets is accompanied by an accuracy cost. Furthermore, colour variation, whether task-relevant or not, leads to an additional cost in processing speed. The results suggest that a divided-effort strategy would improve performance in search tasks such as X-ray baggage screening.