Size, weight, and expectations

Size, weight, and expectations

Smeets, Jeroen B.J. (Vrije Universiteit Amsterdam)
Vos, Kim (Vrije Universiteit Amsterdam)
Abbink, Emma (Vrije Universiteit Amsterdam)
Plaisier, M.A. (TU Delft Human Information Communication Design; Eindhoven University of Technology)

2022

The size-weight illusion is well-known: if two equally heavy objects differ in size, the large one feels lighter than the small one. Most explanations for this illusion assume that because the information about the relevant attribute (weight itself) is unreliable, information about an irrelevant but correlated attribute (size) is used as well. If such reasoning is correct, one would expect that the illusion can be inverted: if size information is unreliable, weight information will be used to judge size. We explored whether such a weight-size illusion exists by asking participants to lift Styrofoam balls that were coated with glow in the dark paint. The balls (2 sizes, 3 weights) were lifted using a pulley system in complete darkness at 2 distances. Participants reported the size using free magnitude estimation. The visual size information was indeed unreliable: balls that were presented at a 20% larger distance were judged 15% smaller. Nevertheless, the judgments of size were not systematically affected by the 20% weight change (differences < 0.5%). We conclude that because the weight-size illusion does not exist, the mechanism behind the size-weight illusion is specific for judging heaviness.

haptics
sensory integration
vision

http://resolver.tudelft.nl/uuid:2e348b98-b453-4e6c-af38-21512cde9157

https://doi.org/10.1177/03010066221087404

0301-0066

Perception, 51 (5), 344-353

Institutional Repository

journal article

© 2022 Jeroen B.J. Smeets, Kim Vos, Emma Abbink, M.A. Plaisier