Abstract
In virtually every real-life situation humans are confronted with complex and cluttered visual environments that contain large amounts of visual information. Because of the limited capacity of the visual system, not all of this information can be processed at a given time. Consequently, items within a scene are competing for attentional resources. But what is the "unit" of this attentional competition? What counts as an item? Here, using fMRI and behavioral measures, we report reduced attentional competition between objects positioned according to commonly experienced configurations, such as a lamp above a table. In an fMRI study designed to measure competitive interactions between objects in visual cortex (Kastner et al., 1998), we found reduced neural competition between objects that were shown in regular configurations. Using a visual search task we then related this reduced competition to improved target detection when distracters were presented in regular configurations. These results indicate that attentional competition is reduced for objects shown in familiar configurations. We interpret the current findings as reflecting the grouping of objects based on higher-level spatial-relational knowledge acquired through a lifetime of seeing objects in specific configurations. This grouping effectively reduces the number of objects that compete for representation. Because scenes contain a large number of objects that occur in regularly positioned groups of two or more objects, such grouping might operate on many objects in a scene to greatly enhance the efficiency of real-world perception.
Meeting abstract presented at VSS 2014