The position of random autokinetic movement and the physiological position of rest are frequently stable and identical

Both the autokinetic illusion (AKI) and involuntary eye movements when a fixation point goes off have been attributed to unmonitored drift eye movements which result from constant features of the oculomotor system. Pilot studies confirmed that the visual directions where these effects had no directional bias, the position of random autokinetic movement (PRAKM) and the physiological position of rest (PPR), were highly correlated and reliable. The more precise main experiment showed that they were usually, but not always, stable and identical. Drifts are therefore not totally due to stable features of the oculomotor system but are a compound of several slow responses which can differ with both stimulus conditions and time. They are not all equally unmonitored.