PUB - Publikationen an der Universität Bielefeld

While it is common wisdom that a salient visual event draws attention, experimental research provided mixed support for this hypothesis. The present experiment seeks evidence that a singleton draws attention to the degree that its feature is novel or unexpected. Two visual search experiments were conducted where an irrelevant colour singleton is presented on each pre-critical trial to familiarize participants with the presence of the singleton. In the critical trial of Experiment 1, the singleton was presented in a novel colour without prior announcement. The singleton was gazed at significantly earlier and longer in the critical trial, as compared to pre-critical trials. This result is consistent with predictions from the expectancy discrepancy hypothesis that colour novelty is sufficient to capture attention. Experiment 2 tested the alternative explanation that a surprising event mainly leads to a breakdown of the previously acquired attentional set, which in turn causes a reorientation towards perceptual salience. An unannounced change of the background colour in the critical trial while the singleton colour remained unchanged did not induce an attentional capture by the singleton like in Experiment 1. This result further confirms that surprising events capture attention in a spatial manner.