Distance Estimates with “Filled” and “Unfilled” Space
Saul M. Luria, Jo Ann S. Kinney, Seymour Weissman · Perceptual and Motor Skills · 1967
To investigate the effect of the "filled-unfilled space" illusion on perception of depth, 40 Os estimated the relative distances of comparison and standard targets when there was a rod from O's chin rest to the standard and when the rod was absent. The apparent distance of the standard was greater when the rod was present.