The Relation between Angle of Display and Performance in a Prolonged Visual Task

Abstract

An experiment is described to test the relation between angle of display and performance in prolonged visual tasks, using the Clock Test in three positions of display surface, vertical, at an angle of 45 degrees to the horizontal, and horizontal. In every case the line of regard was kept at right-angles to the display surface. The results indicate that significantly fewer stimuli are missed in the vertical position of the display surface than in the other two. The deterioration observed in the second half-hour of the original Clock Test experiments was not found in the present experiment, and two possible reasons for this are discussed briefly.