His 1923
In his 1912 monograph on apparent motion, he explored hysteresis and worked with a motion-blind patient, coining the word "phi-phenomenon" to describe the effect produced by a movie theatre marquee.   His 1923 Untersuchungen zur Lehre explained how we perceive non-moving things by organization and not piecemeal; he termed this phenomenon the "bundle-hypothesis." FTP, name this experimenter whose results were extolled by Kurt Koffka in his Introduction to Gestalt Theory.
In his 1912 monograph on apparent motion, he explored hysteresis and worked with a motion-blind patient, coining the word "phi-phenomenon" to describe the effect produced by a movie theatre marquee.   
Max Wertheimer