ATTENTIONAL DISTRIBUTION IN VISUAL SPACE

The horizontal extent of the visual attentive field was measured by th e use of a two-choice-RT task and compatible and incompatible distract ors. The target was a line that inclined either to the left or to the right. Whether or not the subject performed the choice RT was made con tingent upon whether two other stimuli presented in the visual display matched or mismatched. The match-mismatch stimuli varied in locations so as to manipulate the relevant visual area (the attended area). The locations of the distractors were also varied. The increase in RT ass ociated with incompatible distractors was found to vary inversely with their distance from the edge of the area attended to and independentl y of their distance from the target lines. The results were interprete d in terms of an inhibitory field that surrounds the area attended to.