Weight Illusions and Weight Discrimination—a Revised Hypothesis

Abstract

The results of several experiments are reported most of which suggest that there is an optimum density for weight discrimination. This density corresponds to the “non-illusory” density, as determined by the density at which a visible weight is correctly matched with a hidden weight. The greater the illusion (whether of heaviness or lightness) the poorer the discrimination. It is pointed out that similar changes in discrimination occur as a result of peripheral sensory adaptation in many modalities; but that the size-weight illusion, and the associated discrimination changes, must be due to a central scaling process. A theoretical model is suggested.