Dr. Heinrich Liesefeld
Despite the vivid subjective impression of a rich sensory world, people actually process only little information from their environment at a time. Which aspects of the world are processed under which conditions is studied in research on selective attention. Ideally, objects would be prioritized based on their relevance to current behavioral goals. But goals are not the only or strongest influence on selective attention, so that attention is often misdirected and irrelevant objects (distractors) receive prioritized processing. Such “failures” of selective attention are subjectively perceived as distraction; they prevent or delay processing of the concurrently presented goal-relevant objects (targets). The dimension weighting account is a long-standing theory of the various influences on priority computations and selective attention from which I derive unique predictions regarding the circumstances under which distraction occurs. As attention allocations cannot be observed directly, I make use of event-related potentials extracted from the electroencephalogram to test these predictions. The N2pc and PD components are particularly useful markers of attentional enhancement and suppression, respectively. With these tools, I show that distractors standing out in the same visual dimension as search targets capture attention, so that the target can be attended only subsequently. By contrast, distractors standing out in a different dimension are suppressed before they can capture attention, so that target processing is only slightly delayed. The aim of this talk is to convince the audience of the theoretical utility of the dimension weighting account and the empirical utility of the employed event-related-potential components.
