Abstract
Recently, Kimchi and colleagues (Kimchi, Yeshurun, & Cohen-Savransky, PB&R, 2007; Kimchi, Yeshurun, & Sha'shoua, Psychonomics, 2009) presented data demonstrating automatic visuospatial attentional capture by perceptually organized “objects” when a display of nine uniform-sized rotated Ls contained four items arranged to form the corners of a diamond. Specifically, subjects were faster to respond to a cue presented inside the object than they were to respond to a cue presented elsewhere in the display; response times were intermediate when the display elements did not form an object. However, when the display contained an object, the object enclosed a quarter of the display, making it a size singleton. Previous experiments have shown that a size singleton can involuntarily capture attention. By varying the size of the non-object-defining elements in the display, we demonstrate that the status of the object as a size singleton cannot account for the attentional capture found by Kimchi and colleagues. When we made three of the display elements larger than the remaining elements, response times were slowed equally across all object conditions (cue in object, cue outside object, no object), yielding a main effect of size variation. Additionally, we replicated the effect found by Kimchi and colleagues in which the perceptually organized “object” captured attention. Critically, these two effects did not interact—the presence of additional large elements had no effect on attentional capture by the perceptual object. In further experiments, we explore the role of shape in determining attentional capture. Our results suggest elements arranged to form an object do capture attention, even when there is no incentive to allocate attention to the object compared to other parts of the display.
NIH grants R01 DA13165 and T32 EY07143.