Sensation and Perception Demonstrations of the size-weight illusion. David T.Homer and K.Desix Robinson
Charpentier (1891) first introduced the size-weight illusion. When lifting two objects that are identical in weight but different in size, the larger object seems to be lighter than the smaller object. Several cues affect the strength of the illusion including cutaneous information (McCloskey, 1974), haptic information (cues obtained when the hand lifts an object; Amazeen & Turvey, 1996; Ellis & Lederman, 1993), and visual information (for a review, see Jones, 1986). Because different cues affect illusion strength, demonstrations of the illusion provide excellent opportunities to discuss how theories must account for different facts and the importance of experimentally controlling for extraneous variables. Demonstrations of the illusion also illustrate the importance of designing experiments to generate empirical evidence that differentiates between competing theories.