THE UPPER SPEED THRESHOLD FOR THE DISCRIMINATION OF VISUAL MOVEMENT AS A FUNCTION OF STIMULUS LUMINANCE

摘要

The problem of the present report was to determine how stimulus luminance affects the upper speed threshold. The observer viewed the center of a circular black area surrounded by a dimly illuminated area. The moving spot of white light traversed the path of a horizontal line cen­tered in the circle. At high speeds, the observer reported a stationary line and could not indicate the direction of movement. At slow speeds, he indicated the direction (right or left). Two subjects made 50 responses, one 26 responses, to each of several combinations of luminance and speed of the moving spot. The speed and luminance were systematically varied in a counterbalanced order.