The apparent paths of two or three circularly moving spots

Summary Two or three circularly moving luminous spots presented side by side in a dark room were observed under non-restrictive conditions, instead of pursuing a particular spot with the eyes. The experimental variables were speed, direction (clockwise or counterclockwise) and the phase difference between the moving spots. The paths of the circularly moving spots appeared to be a circle, an ellipse, or a straight line. With the three phase differences of 0°, 90°, and 180°, the paths appeared to be horizontally, obliquely, and vertically elongated ellipses, respectively. The direction difference from the other moving spots could affect the size of the apparent path. The speed had the most remarkable effect on the apparent paths. The perceptual vector analysis is applicable under slow speed conditions in the present experiments with a display of relatively large visual angle.This study was conducted in The Psychological Laboratory, Keio University in Yokohama