The material-weight illusion revisited

Percept Psychophys. 1999 Nov;61(8):1564-76. doi: 10.3758/bf03213118.


Experiment 1 documents modality effects on the material-weight illusion for a low-mass object set (58.5 g). These modality effects indicate that the material-weight illusion is principally a haptically derived phenomenon: Haptically accessed material cues were both sufficient and necessary for full-strength illusions, whereas visually accessed material cues were only sufficient to generate moderate-strength illusions. In contrast, when a high-mass object set (357 g) was presented under the same modality conditions, no illusions were generated. The mass-dependent characteristic of this illusion is considered to be a consequence of differing grip forces. Experiment 2 demonstrates that the enforcement of a firm grip abolishes the low-mass material-weight illusion. Experiment 3 documents that a firm grip also diminishes perceptual differentiation of actual mass differences. Several possible explanations of the consequences of increasing grip force are considered.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Discrimination Learning
  • Female
  • Hand Strength
  • Humans
  • Illusions*
  • Male
  • Psychophysics
  • Size Perception
  • Stereognosis
  • Touch*
  • Visual Perception*
  • Weight Perception*