A historical note on illusory contours in shadow writing

摘要

It is widely accepted that illusory contours have been first displayed and discussed by Schumann (1900, Zeitschrift fur Psychologie und Physiologie der Sinnesorgane 23 1-32). Here we show that, before him, Jastrow (1899, Popular Science Monthly 54 299-312) produced illusory contours consisting of a shadow word. A brief history of shadow writing in psychological literature from Jastrow to Brunswik is presented, in which the contributions of Pillsbury, Warren, Koffka, and Benussi are examined.