Role of focal attention on latencies and trajectories of visually guided manual pointing.

Previous studies have shown that an odd-colored target among uniformly colored distractors can be rapidly detected and localized using broadly distributed attention over an entire display. In the current study, we show that such a broadly distributed attentional allocation is not sufficient for seemingly effortless goal-directed manual pointing. Latencies and movement durations of manual pointing in odd-colored search tasks become shorter and curved trajectories decreased as the number of distractors increase or target color repetitions increases. Because these manipulations have been shown to facilitate the deployment of narrowly focused attention to a target but not for distributed attention, this adds further support to the view that focal attention is necessary for goal-directed action. In addition, the presence of highly curved movement trajectories, directed first to a distractor then to the target reflects ongoing changes in focal attentional deployment and target selection.