Abstract
This study examines the effects of visual feedback's discreteness on fine positioning tasks. An experiment is performed in which computer's mouse is positioned under human's eye-hand coordination. In the experiment the following three factors were examined; a form of visual feedback, i.e. analog and digital, a Control/Display ratio and a cycle time of visual feedback. Results are summarized as follows. Movement Time (MT) becomes larger for the digital feedback and with the cycle time because of the discreteness of the visual feedback. In case that the cycle time is smaller than 240msec, however, no improvement of the performance is observed, because human's reaction can't catch up with the feedback cycle. The value of 240msec is well coincident with the simple reaction time for the Model Human Processor proposed by Card et al. These results are useful to design a Man-Machine-Interface and manage its priority under a multitask environment.
