Weight Illusions

Weight perception and weight illusions

When lifting an object and judging its weight, individuals will often experience that something is lighter or heavier than it actually is. The subjective nature of our perceptions of heaviness is such that identically-weighted objects can be made to feel as if they have substantially different weights from one another. In the size-weight illusion, for example, small objects feel substantially heavier than equally-weighted large objects. And, in the analogous material-weight illusion, objects which appear to be made from a low-density material will feel heavier than objects of the same mass which look as if they are made from a higher-density material. At a descriptive level, the illusory misperception of weight contrasts with their prior expectations; the light-looking object is heavier than the lifter expected, causing them to experience it as being heavier than it actually is (and vice versa). However, the mechanism behind these illusions is far from clear. We are working toward understanding the psychological and physiological factors which drive our experience of how heavy things feel.