Calibration of Distance and Size Does Not Calibrate Shape Information

This study investigated the coupling of distance and size perception as well as the coupling of distance and shape perception. Each was tested in 2 ways using a targeted reaching task that simultaneously yielded measures of distance, size, and shape per-ception. First, feed-forward reaches were tested without feedback. Errors in size did not covary with errors in distance, but errors in shape did. Second, reaches were tested with visual feedback. Estimated distance and size became more accurate, but shape did not. The evidence indicated that distance and size perception and distance and shape perception are not coupled. These results were replicated 3 times as we also compared performance using dynamic monocular, static binocular, and dynamic binocular vision. Performance was better with binocular than monocular vision both without and with feedback. The presence of a size gradient did not improve monocu-lar distance perception, yielding additional evidence that distance and size percep-tion are not coupled. The use of vision to control reaching is quite complex. A number of spatial proper-ties of a target object must be perceived to control a reach to grasp the object. The properties include the object’s distance, size, and shape. Distance is needed to con-trol reaching. Size and shape are needed to control grasping. It has often been as-sumed that these properties are coupled in space perception. For instance, the clas-sic size–distance invariance hypothesis assumes that the perception of distance and

Binocular vision · Calibration · Computer vision · Depth perception · Monocular · Monocular vision · Perception · Statistics · Computer Science · Mathematics · Motor Control and Adaptation · Psychology · Tactile and Sensory Interactions · Visual perception and processing mechanisms · Artificial Intelligence