Rapid parallel allocation of attention to multiple objects.

Serial models of visual search postulate a unitary focus of spatial attention that moves sequentially between candidate target objects at different locations. This implies that the allocation of attention to a new object will be preceded by the de-allocation of attention from its previous location. In contrast, alternative parallel models assume that focal attention can operate simultaneously at multiple target locations. In recent ERP studies, we employed the N2pc component as an on-line electrophysiological marker of attentional target selection to show that when two colour-defined target objects appear at different locations in rapid succession (with stimulus onset asynchronies between 10 and 100 ms), two parallel foci of attention are established, each with its independent time course (Eimer & Grubert, 2014; Grubert & Eimer, 2014). We will discuss this recent evidence for rapid parallel allocation of attention to multiple objects, and present new findings from a series of studies that explored the nature of this fast and flexible attentional control mechanism. These new results demonstrate that rapid parallel selection is not restricted to conditions where two colour-defined targets are presented sequentially. Multiple parallel attentional foci are also activated when two targets are presented simultaneously, when target objects are defined by other feature dimensions than colour, and even in search tasks where more than two targets are presented in rapid succession at different locations. We also show that attentional control processes are sensitive to temporal sequence information that is inaccessible to conscious report. These findings demonstrate the dynamic nature and flexibility of attentional selectivity in time and space. Meeting abstract presented at VSS 2015.