A new illusion: The underestimation of distance during pursuit eye movements

A new visual illusion is reported. The apparent distance through which a displaced target appears to move is significantly shorter when pursuit tracked than when that same distance is observed by means of a saccadic eye movement. This misperception of distance seems to be related to the Aubert-Fleischl paradox, the underestimation of the velocity of a tracked target, and to reveal a consistent characteristic of the pursuit eye movement system.