Oculomotor adaptation to wedge prisms with no part of the body seen

When S looks at a visual target through prisms, adaptive shifts in reaching behavior occur even though he sees no part of his body through the prisms. These shifts are caused by a change in the judgment of the direction of gaze (oculomotor change), which in turn is caused by two secondary prismatic effects: (a) asymmetry of the visual display and (b) apparent rotation about a vertical axis of a panel or wall facing S. The “asymmetry” factor contributes 22% of the total oculomotor change, and the “rotation” effect contributes the remaining 78%. Oculomotor change is not facilitated by eye-movement activity. The adaptive oculomotor change induces a non-adaptive proprioception change about one-tenth as large as the oculomotor change. These findings are capable of accounting for the previously unexplained results reported by Wooster in 1923, and also for the current controversy about the role of reafferent stimulation in sensorymotor adaptation.     

A method for sensation scaling based on an analogy between perception and judgment

Two techniques for studying judgment are discussed. In the first of these one assumes invariance of perception over different judgment processes and conceives of the properties of one judgment process as known. Then, perceptions may be estimated under this process and utilized in the study of other judgment processes of interest. A second technique disposes of the reliance up on a basic, “known” process and instead suggests that perception be treated as free parameters to be estimated from data. The paper then proceeds to show how this second technique may be used under certain conditions on perception themselves. A concept of sensation is introduced which is thought of as generating percepts in formally the same manner as percepts are thought of as generating judgments. The idea is tried out on the perception of movement time. A simple perception process appears to give a good fit to data.     

Oculomotor adaptation to wedge prisms with no part of the body seen

When S looks at a visual target through prisms, adaptive shifts in reaching behavior occur even though he sees no part of his body through the prisms. These shifts are caused by a change in the judgment of the direction of gaze (oculomotor change), which in turn is caused by two secondary prismatic effects: (a) asymmetry of the visual display and (b) apparent rotation about a vertical axis of a panel or wall facing S. The “asymmetry” factor contributes 22% of the total oculomotor change, and the “rotation” effect contributes the remaining 78%. Oculomotor change is not facilitated by eye-movzment activity. The adaptive oculomotor change induces a non-adaptive proprioception change about one-tenth as large as the oculomotor change. These findings are capable of accounting for the previously unexplained results reported by Wooster in 1923, and also for the current controversy about the role of reafferent stimulation in sensorymotor adaptation.