Art and the brain: the influence of art on Roger Shepard's studies of mental rotation

This paper explores the influence of visual sources on Roger N. Shepard's 1971 mental rotation experiments and the centrality of ambiguity as one of his experimental and artistic concerns. Sources include Shepard's statements about ambiguity as expressed in the book, Mind Sights, and a recent interview. Parallel investigations of ambiguity by the contemporary artists Al Held and Robert Smithson are considered. Shepard utilized a wide range of visual sources while formulating his experimental design, namely Necker cube illusions, hypnopompic images, René Magritte, and M.C. Escher. In addition, he drew upon key art historical theses of the time, such as Ernst Gombrich's theories about schemas. For Shepard as for Gombrich, the world of appearances is a world of ambiguity.