The material-weight illusion revisited.
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.
Ellis
R R
RR
Psychology Department, Queen's University, Kingston, ON, Canada. robert.ellis@bangor.ac.uk
Lederman
S J
SJ
D000328:Adult; D004193:Discrimination Learning; D005260:Female; D018737:Hand Strength; D006801:Humans; D007088:Illusions; D008297:Male; D011601:Psychophysics; D012858:Size Perception; D013236:Stereognosis; D014110:Touch; D014796:Visual Perception; D014892:Weight Perception