The Origin of the Autokinetic Effect

Abstract

The effects of unbalanced fatigue of the ocular and neck musculature on the auto- kinetic effect are described. It is shown that after deviation of the eyes to an extreme position, fixation of a small light source with the eye in the central position gives rise to an immediate and pronounced autokinetic effect. This apparent movement is typically in the same meridian as that of the ocular deviation and is often, at all events at first, in the opposite direction. Similar, though less clear-cut, results are obtained after induction of unbalanced fatigue in the neck musculature. It is argued that the autokinetic effect observed under these conditions warrants treatment as a primary illusion of movement and does not involve a “framework” or standard of reference. In an appendix, a speculative model of the ocular control system and some preliminary observations are presented. It is concluded that the autokinetic effect is principally due to spontaneous minor fluctuations in the neural system which monitors the outward signals controlling eye movement.