ABSTRACT
J.J. Gibson’s seminal insight regarding the pick-up of higher-order invariants in the optic-array was outlined by 1950, one decade before the recent wave of neurophysiological advances which began in the early 1960’s. Gibson stressed motion, especially the global field of velocities, as particularly important, both for the delineation of surface properties (Gibson, 1950) and for the perception of self-motion (Gibson, 1958). Electrophysiological recordings from cortical area MT in primate reveal cells which are sensitive to differences in velocity between adjacent portions of the visual field (Allman, Miezin, & McGuiness, 1985). Such mechanisms are likely to encode just those variables that Gibson understood as important for vision: velocity differences rather than absolute values of velocity (see Nakayama & Loomis, 1974; Frost & Nakayama, 1983). Thus Gibson’s insight was perhaps prophetic, yet in ways not personally anticipated, since his own outlook eschewed a concern for necessary details of neural computation.
