Visual Displacement During Manual Aiming

Abstract

<p> Four experiments were conducted to examine the visual regulation of manual aiming under visually displaced conditions. A secondary purpose of these studies was to examine potential gender differences in behaviour following prismatic displacement. The initial experiment was designed to test a monocular switch of vision as a method of presenting the visually displaced information. This experiment also provided an opportunity to explore manual and ocular asymmetries. The monocular switch had no major influence on the terminal accuracy of the movements. Therefore. the methodology was employed to present visually displaced information in the three subsequent experiments. The second experiment was designed to present visually displaced information at different times during the aiming movements. while the third experiment was designed to remove the displaced information during the movements. In a fourth experiment. a real time movement analysis procedure was used to introduce visual displacement at various kinematic markers. In Experiments 2, 3, and 4. the early presentation and removal of the visually displaced information had the most influence on terminal accuracy. However. these effects were not consistent across gender. Male participants executed their movements based on the information presented prior to the movements. In contrast. female participants were more influenced by the information received during the initial portions of the movements. The results support models of manual control that emphasize the importance of vision in the early portions of the movement for the correction of trajectory errors. The effects involving gender suggest that gender should be included as an independent variable in future research. </p>