Object-related attention: an event-related potential study

In two experiments reaction time (RT) and event-related potentials (ERPs) were measured to visual stimuli consisting of two objects (Duncan, 1984; Vecera & Farah, 1994). Target stimuli were defined by two features, which either were distributed between the two objects or belonged to a single object. In Experiment 1 the two objects appeared in spatial overlap, whereas in Experiment 2 the two objects were spatially separated. In both experiments RT was shorter in the single-object condition. The late positive component of the ERP (P3) emerged, peaked, and declined earlier in the single-object condition. It is suggested that object-related attention may facilitate the earlier onset of search for the relevant features.