Search

STIMULUS variables influencing the perception of the third dimension and rate of perceived reversals1–7of the Necker cube (Fig. 1a–c) and the Mach book (Fig. 1d) have been examined, and although the Necker cube has been viewed as an ambiguous figure whose configuration and accompanying instructions usually limit the number of percepts to two4, few studies have asked what the observer perceives the figure to be8,9. We show here that the perceptual structure of the Necker cube is far more ambiguous than previously suggested.