Abstract
Eye movements are tightly coupled to an unexpected extent with ongoing motor actions in everyday activities, such as food preparation (Land and Hayhoe, 2001). Considering the fact that eye movements are usually preceded by the deployment of focal visual attention, we ask whether there is a similar dependence of motor actions on attention. Are signature characteristics of focal attentional deployment also seen for motor tasks more generally? In particular, will visual guided motor actions show decrease in latency as a function of distractor number (Bravo and Nakayama, 1992), will they exhibit the “gap” phenomenon (Fischer and Breitmeyer, 1987), and will they show color priming (Maljkovic and Nakayama, 1994)?
Colored stimuli were presented on a touch screen and subjects were asked to point as quickly as possible to the odd colored target among distractors. We found that the specific pattern of results seen for attentional deployment was mirrored in the results obtained in our pointing task. Latencies decreased with increasing number of distractors but only when target and distractor colors were randomly switched. The “gap” effect was shown and found to be determined by the disappearance of the fixation mark itself rather than by a non-specific warning property of the event. The consecutive repetition of a given colored target gradually decreased manual pointing times and thus showed cumulative priming effects. These results suggest that visually guided motor actions are closely coupled to the deployment of focal attention.