Movement and focused attention: a failure to replicate.

Our original goal was to explore the nature of the grouping-by-movement phenomenon reported by Driver and Baylis (1989). In their studies, distractors that moved in common with a centrally located target had a larger influence on focused-attention performance than did more proximate but stationary distractors. These results seemed particularly important since they suggested, contrary to the predictions of space-based models of attention, that attention could be allocated to noncontiguous regions of the visual field. Their results also suggested mandatory processing of stimuli with common motion. Unfortunately, we were unable to replicate this grouping-by-movement effect. In the conditions of Experiment 1 in which we replicated Driver and Baylis's methodology, stationary distractors produced a larger response-compatibility effect than did the more distant distractors that moved in common with the target. In Experiment 2, we redundantly coded the centrally located target and the far distractors with common movement and color. However, the results were identical to those obtained in Experiment 1. The stationary near distractors that appeared in a different color from the target and the far distractors produced the largest response-compatibility effect. In a final experiment, we attempted to compensate for the reduced acuity of the moving distractors by adjusting their size by a cortical magnification factor. However, even with this manipulation, we found a larger response-compatibility effect for the stationary near distractors than for the moving distant distractors. Our results suggest that subjects are capable of selectively processing a target item that moves in common with distractors.