Does the Vigilance Decrement Occur for Elementary Features?

Abstract

The aim of the current study was to determine whether the vigilance decrement occurs when observers search for a critical signal that consists of an elementary feature (line orientation). Elementary features are processed quickly and presumably with minimal attentional resources (Treisman & Gormican, 1988). Such features should be resistant to the vigilance decrement, according to theories of the decrement that posit depletion of attentional resources as the underlying mechanism. Observers completed a vigilance task in which they reported the presence of a critical signal, which consisted of a slanted line presented amidst vertical lines. A vigilance decrement was evident in correct detections and reaction time. In a follow-up study, a pop-out effect for the slanted line was replicated in a traditional search task. To the extent that an elementary feature is processed preattenatively, the occurrence of a vigilance decrement challenges theories of the decrement based on depleted attentional resources. However, whether elementary features are processed without attention has been debated and further studies are needed. Identifying display characteristics that can be processed automatically without depleting attention will enhance monitoring performance by eliminating the decrement in safety critical tasks such as aviation and baggage screening.