Evidence for selective target processing with a low perceptual load flankers task.

Abstract

In this article, we demonstrate that selective target processing is possible when the perceptual load of the task is low. We presented a row of three items with two different identities: one identity for the target letter and one for the two flankers (B. A. Eriksen & C. W. Eriksen, 1974). Such stimulus arrays have been defined as low-load displays (Lavie & Tsal, 1994). We investigated whether subjects could ignore the irrelevant flankers, which were never response alternatives, by manipulating the predictive relationship between the flankers and the response (Miller, 1987). In a high-correlation block, the identity of the flankers was highly predictive of the target identity, whereas in a low-correlation block, the predictive value of the flankers was reduced. We varied (1) whether or not the target location was precued, (2) the flanker's category (digit vs. letter), (3) the target-flanker proximity (near = .3 degree vs. far = 5 degrees), and (4) the size of the characters. The results indicate that subjects were influenced by the predictive value of near flankers and that the magnitude of this effect was jointly modulated by the target-flanker categorical overlap and by the size of the characters. In contrast, null flanker effects were obtained for far letter flankers in the precue condition, and for far digit flankers, regardless of attentional cuing. These findings (1) are inconsistent with suggestions (Lavie, 1995) that irrelevant stimuli automatically capture attention, and (2) support the notion that target-flanker distinctiveness plays a role when the perceptual load of the task is low.