A cuing study of the N2pc component: an index of attentional deployment to objects rather than spatial locations.

Symbolic visual cues indicating the location of an upcoming target are believed to invoke endogenous shifts of attention to cued locations. In the present study, we investigated how visual attention is shifted during such cuing paradigms by recording event-related potentials (ERPs). We focused on a component known to index lateralized shifts of perceptual attention during visual search tasks, known as the N2pc component. The ERP data show that attention was shifted to a cued location in anticipation of a target shape when the location is marked by a placeholder object (Experiments 1 and 2). However, when the possible locations were not marked by placeholder objects, we found no evidence for an anticipatory shift of attention to the cued location (Experiment 3). These findings indicate that the perceptual attention mechanism indexed by the N2pc is deployed to objects and not simply locations in space devoid of object structure.