1 Eros, Thanatos and scenebased theories of MüllerLyer and Poggendorff illusions Alexander W. Pressey Winnipeg, Canada Abstract A distinction between analytic approaches employed by scenebased theories of geometric illusions and by scenebased investigations of “ subliminal” advertising is sought. Proponents of scenebased theories of geometric illusions (e.g., Gillam, 1971; Gregory, 1963; Redding and Vinson, 2010) often provide a picture or a drawing of a 3D object such as the building shown in Figure 1A. They then trace out features of the building to show how they represent a 2D geometric illusion. In the case of Figure 1A, the interior and exterior corners are considered to be 3D versions of expansion and shrinkage forms of 2D Müller–Lyer’s drawings. Figure 1B depicts a “…Poggendorff pattern [bold lines]…with pictorial scenes within which a viewer might subconsciously embed those patterns (thin lines)” (Parks, 2009, p. 142). Figure 1(A) Representations of 3D objects within which 2D MüllerLyer figures are sketched (Adapted with permission from Schloss & Prinzmetal, 2012; original by Preeti Talwai) (B) Reproduced from Parks, 2009; see text for explanation) Proponents of the theory that corporations employ representations of Freud’s two basic instincts, i.e., sex and aggression, in subliminal advertising provide pictures such as those shown in Figures 2A and 2B. In 2A, the word “SEX” is carefully sketched out in the palm trees and in 2B the skull in the ice cube is circled. A B