Involuntary capture of visual-spatial attention occurs for intersections, both real and "imagined".

In three spatial precuing experiments, we demonstrate attentional capture by an intersection that occurs (1) between two lines that are not part of an enclosed object, and (2) between a line in the cuing array that is not physically present during target search and the invisible circumference of a perceptual circle formed by the elements in the target array. This capture effect conceptually replicates Cole, Gellatly, and Blurton's (2001) corner enhancement effect, in which responses are faster for targets presented near an object's corners rather than along its straight edges. However, it extends that effect by showing that it occurs even when the intersection is not part of an enclosed object and is not physically present during target search. More important, our capture effect occurred even though the target's position was not designated by a perceptually distinctive feature and was not predicted by the intersection's position. Thus, it seems that a line intersection--whether it be real or imaginary-automatically captures visual-spatial attention, contrary to Folk, Remington, and Johnston's (1992) and Gibson and Kelsey's (1998) views that such an involuntary capture of spatial attention is contingent on attentional control settings.