Non-Informative Effects of Stimuli Functioning as Cues

Abstract

The category of a first stimulus (S1) serving as a cue may allow a subject to predict the category of a second stimulus (S2). However, a cue may have effects on RT to S2 that are independent of those derived from its intended role as a predictor. These non-informative effects of a cue may add to or subtract from the benefits associated with its predictive function. Two experiments demonstrate that when S1 is in the same category as S2 (as is frequently the case for valid cues in cueing experiments) but provides no information about S2, RT is slower than when S1 is in a different category from S2. It is suggested that this category relation effect arises because inhibition of a response to S1 is still present when S2 arrives and that, in some cueing experiments, it may subtract from the RT benefits derived from the cue as a predictor of S2. Also, RT to a visual but not to an auditory S2 was faster after an auditory S1 than after a visual S1. It is argued that this modality combination effect is consistent with the view that auditory signals are more alerting than visual ones and that this is another factor to be taken into account in the design of cueing and other experiments.