Distinct Mechanisms for Distractor Suppression and Target Facilitation.

If you were told to ignore a white bear, you might find it quite difficult. Holding something in working memory is thought to automatically facilitate feature processing, even if doing so is detrimental to the current task. Despite this paradox, it is often assumed that distractor suppression is controlled via similar top-down mechanisms of attention that prepare brain areas for target enhancement. In particular, low-frequency oscillations in visual cortex appear especially well suited for gating task-irrelevant information. We describe the results of a series of studies exploring distractor suppression and challenge this popular notion. We draw on behavioral and EEG evidence to show that selective distractor suppression operates via an alternative mechanism, such as expectation suppression within a predictive coding framework.