Abstract
When a horizontally elongated surface is occluded in the middle by a larger surface, it appears narrower than its true width (Kanizsa's compression illusion). We report that a similar compression effect occurs for closed-loop visuomotor matches of size, but not for otherwise comparable open-loop reaching or memory matching actions. Grasping actions in personal space were performed with both hands on relatively large surfaces. Precision grips performed on smaller surfaces with the thumb and index fingers proved extremely variable. Implications for the current debate on the existence of dissociations between spatial perception and grasping actions in personal space are discussed.
Supported by Murst n. 9911333852 and by the University of Trieste.