Conjunction in simulated railway signals: a cautionary note

Abstract

Train drivers routinely perform visual search tasks to locate combinations of coloured signals controlling their progress, and are required to make discrete decisions on the basis of what they see. Two studies are reported which examine the performance of students under conditions that simulate critical aspects of United Kingdom train drivers' signal-response task. The most crucial cautionary signal, the single yellow signal used to alert a transition to potentially hazardous situations, was responded to more slowly than other signal types. A longer processing time was found whether (Study 2) or not (Study 1) the signal appearance was accompanied by the auditory warning signal train drivers encounter under actual driving conditions. The results are consistent with predictions from Treisman and Gelade's (1980) Feature Integration Theory, and the implications for signal sighting practice are discussed. Copyright © 2005 John Wiley & Sons, Ltd.