Real and apparent movement nulled

Abstract

It is a controversial issue whether ‘real’ movement, seen from the successive stimulation of retinal receptors by a moving image, and ‘apparent’ (phi) movement, which is produced by stimuli separated in space and time, are transmitted by the same or different neural channels. With this question in mind, we have devised ways to oppose real against opposite-direction apparent movement, to see whether they cancel. Cancelling, especially in a variety of conditions, would be expected for a single but not for separate neural movement channels. As we report here, we find that opposed-direction real and apparent movements will cancel, allowing null measurements to be made.