Belopolsky & Kramer, Electrophysiological analysis of visual marking Abstract Visual marking is an attentional mechanism that enables observers to selectively search through new information in a visual field. In a visual marking task search items are presented in two sets, separated by a time interval (gap interval), and with the second set containing the target. ERPs were used to investigate whether visual marking operates during the gap interval. Premasks, created by overlapping all possible stimulus segments, were used to generate the search items. ERPs were recorded to the probe, presented at the old and new locations in the gap interval. Significant differences in N1 and P300 components were found, with the amplitude larger at the locations of the new objects, indicating differential allocation of attention.