Monitoring the visual environment for targets has evolutionary and ecological significance. Exploration of the visual scene can be hypothesized to use "saliency maps" representing the priorities allocated to different locations and features, which change dynamically based on previous experience. This is supported by the observation that sequential effects influence the speed and accuracy of visual search tasks. Yet, the mechanisms underlying these effects are not well understood. Here we used electrophysiological methods to identify some of the mechanisms underlying a specific sequential effect-the distractor previewing effect (DPE). We found that the DPE is correlated with electrophysiological indices of attention allocation but not with sensory or motor components, suggesting that the DPE is related to attentional phenomena, rather than perceptual or motor levels of processing.