Natural Oculomotor Performance in Looking and Tapping Tasks

A unique apparatus recorded eye and head movements of subjects as they tapped or only looked at sequences of 2, 4 or 6 nearby, 3-D targets. Each sequence was repeated 10 times to allow an opportunity for learning. A stereotypical pattern of movements was established after 2-3 repetitions. Subjects almost always looked at each target just before tapping it. Looking-only was more difficult than tapping in that it took more time and, unlike tapping, usually did not benefit from practice. The number of targets in a sequence affected timeA^get in both tasks. Sequence length and practice effects show that memory was involved. The persistent strategy of looking before tapping and the subjects' inability to tap a well-leamed patten with eyes closed, show that visual cues were also important We conclude that motor plarming occurred first at the level of the task and then at the level of specific motor programs. The relative difficulty of the less natural, looking-only task, in which the eyes worked without a meaningful cognitive or motor purpose, suggests that efficient eye movement programming requires a natural task of the kind eye movements evolved to serve

The function of visual search and memory in sequential looking tasks

Eye and head movements were recorded as unrestrained subjects tapped or only looked at nearby targets. Scanning patterns were the same in both tasks: subjects looked at each target before tapping it; visual search had similar speeds and gaze-shift accuracies. Looking however, took longer and, unlike tapping, benefitted little from practice. Looking speeded up more than tapping when memory load was reduced: memory was more efficient during tapping. Conclusion: eye movements made when only looking are different from those made when tapping. Visual search functions as a separate process, incorporated into both tasks: it can be used to improve performance when memory load is heavy

The function of visual search and memory in sequential looking tasks

Eye and head movements were recorded as unrestrained subjects tapped or only looked at nearby targets. Scanning patterns were the same in both tasks: subjects looked at each target before tapping it; visual search had similar speeds and gaze-shift accuracies. Looking, however, took longer and, unlike tapping, benefitted little from practice. Looking speeded up more than tapping when memory load was reduced: memory was more efficient during tapping. Conclusion: eye movements made when only looking are different from those made when tapping. Visual search functions as a separate process, incorporated into both tasks: it can be used to improve performance when memory load is heavy. Saccades Visual search Memory Visuomotor coordinatio