Purchase this article with an account.
Yusuke Tani, Yutaka Nakajima, Kazushi Maruya, Takao Sato; The role of the visual feedback on the pointing behavior. Journal of Vision 2005;5(8):129. doi: 10.1167/5.8.129.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: When we point an object with a finger, the control of the arm and finger may be conducted by using a feedback loop involving vision, but it could be carried on solely by motor system without visual involvement especially when we point a target very quickly. To clarify the mode of control, or the involvement of vision in pointing behavior, we measured and compared the accuracy of pointing in conditions with and without visual feedback.
Method: Eight right-handed students participated. They were asked, to point a target (as quickly as possible) using their right hand. The target was a small dot displayed on a screen 228 cm away from the subjects. The target was on the medial plane of subjects' eye height. The points actually pointed by subjects were measured from the image projected on the screen by a small laser pointer that emits red light and affixed to the subjects' forefinger. There were two conditions. In one, feedback condition, subjects could see their arm and hand through the green glasses as well as the target. In the other, no-feedback condition, subjects saw only the target through a head mounted display connected to a video camera. They could not see their arm and hand. The location and the size of target were the same between the two conditions. In either condition, subjects did not have feedback from the point projected by the laser pointer since they wore either green glasses or head mounted display to prevent seeing the point. Each subject had 20 trials for both conditions.
Results: The accuracy was generally worse in the no-feedback condition than in the feedback condition. In addition, there was a systematic deviation towards right in the no-feedback condition. These results, together, demonstrate importance of visual feedback in pointing behavior.
This PDF is available to Subscribers Only