VISUOMOTOR CONTROL OF THE RELATIVE MOVEMENT OF RANDOM-DOT PATTERNS

A series of experiments were made on human performance in controlling optical relative movement. The aim was to test the influence of differ ent kinds of relative movement on visually controlled steering tasks. Within adjacent displays on a computer screen random dot patterns move d in a fixed direction at continually changing speeds (Exp. 1) or at c onstant speed and in continually changing directions (Exp. 2). The sub ject was required to compensate for the unpredictable modulations of t he pattern movement by means of an isometric joystick. The task was to adjust relative movements involving pure translation, symmetric conve rgence, divergence, or shear. Analysis indicated that the task perform ance was not dependent on the special kind of relative movement. Howev er, performance was significantly higher in tasks where directionally disturbed relative movement had to be controlled compared to those sit uations in which relative movement varied with respect to speed.