Cohen, R. L. Velocity perception—centrally or retinally organised?Scand. J. Psychol., 1961, 2, 45–48.—5 subjects were asked to estimate (a) the relative and (6) the absolute velocities of two spots moving in a simple harmonic motion, 180° out of phase under two experimental conditions: (1) both spots projected on to bothretinas, and (2) one spot projected on to one retina and the second on to the other. Theresults were precisely the same under both conditions. This was taken as indicating that(a) the organisation of velocity perception is central rather than retinal, and (b) the effect of interference caused by one spot when trying to estimate the velocity of the other (the signal) is not lessened when the interference is fed into the eye other than the one receiving the signa