The center of projection.
Our ability to manipulate ourselves and the objects which surround us in our object space depends upon reasonably precise localization of the perceived images of these objects in our visual space. To be functionally sensible, this premise suggests that a "center of projection" must be located somewhere on the subject's body. Two studies which were done in an effort to illuminate an earlier study in regard to the center of projection are reported. One study used an "optical gun" which forced the subject to "shoot" at a perceived target. A second study used a focused beam headlamp to indicate the perceived direction of a perceived target. The perceived direction of the targets was altered by changes in the accommodative stimulus. Since the subject was aware only of the perceived direction of the image and since, in addition, he could not see the results of his efforts to localize the target, the location of a fixed center of projection could not be demonstrated.
D005246:Feedback; D006801:Humans; D008722:Methods; D013028:Space Perception; D014796:Visual Perception