An Analysis of Eye Movements during a Visual Task

Abstract

The distributions of the interval of saccadic movements during different visual situations were analysed. These distributions were composed of three kinds of movement which have different properties; involuntary, voluntary and fixation. Involuntary movements occurred when a subject ran his eyes along a line, or when he searched some targets on an object. Also, corrective movements to a fixation point were considered as involuntary. The interval of these movements was less than 270 msec. When the subject voluntarily moved his eyes among targets in succession, the intervals were distributed from about 270 msec to 500 msec. In the case of more than about 500 msec, the subject gazed at a target carefully, or he was not required to see any special object. From those results, a side view of a visual task may be inferred from an analysis of the interval of saccadic movements. Furthermore, a criterion for the estimation of the load of a paced visual task, such as an inspection task on a conveyor belt, may be proposed.