Within-Trial and Across-Trials Habituation Mechanisms to Irrelevant Visual Transients

Observers can learn to resist distraction in visual search when feature singletons or luminance transients are repeatedly presented across trials at a given location. In this study, we investigated whether the same repetition benefit would be observed when luminance transients are repeatedly shown at the same location within the same trial, and how this effect relates to across-trials habituation of attentional capture. The results showed that interference was reduced when four luminance transients were presented at the same location before target appearance, compared to when a single transient was presented, replicating the feature singleton findings. Furthermore, the magnitude of this repetition effect did not depend on the local and global across-trials probability of repeated and single transients, supporting the hypothesis that two relatively independent within-trial and across-trials habituation mechanisms coexist. Finally, in Experiment 4, we demonstrated that the repetition effect was largely reduced when the first three transients appeared at a different location, ruling out the possibility that the repetition benefit was simply because of a warning effect and/or the spatial predictability of the last visual transient.