Affiliations: [a] University of West Florida, Pensacola, Florida | [b] Naval Aerospace Medical Research Laboratory, NAS, Pensacola, Florida | [c] Massachusetts Institute of Technology, Cambridge, MA 02139
Note: [1] This paper, presented by the first author in a symposium organized by Professor Makoto Igarashi, April 1990, Houston, Texas, focuses on comparison of perceived spatial orientation change during acceleration and deceleration of centrifuge runs in a series of experiments. To simplify presentation, the direction of rotation of centrifuge runs is described as counterclockwise in Series 1, 2, and 4. When subjects are positioned in forward-facing tangential heading on the centrifuge, angular acceleration generates a mild pitch-up orientation change and deceleration generates a strong confusing pitch-down orientation change irrespective of whether the centrifuge rotation is clockwise or counterclockwise. In Series 2, which focused on the vestibulo-ocular reflex, direction of rotation was clockwise for the forward-facing configuration and counterclockwise for the backward-facing configuration.
Note: [*] Reprint address: F.E. Guedry, PhD, Department of Psychology, University of West Florida, Pensacola, FL 32514.
Abstract: The dynamics of spatial orientation perception were examined in a series of experiments in which a total of 43 subjects were passively exposed to various combinations of linear and angular acceleration during centrifuge runs. Perceptual effects during deceleration were much stronger than effects during acceleration. The dynamics of spatial orientation perception differed substantially from changes in the vestibulo-ocular reflex (VOR). VOR was fairly well predicted by a current model, but our experiments revealed perceived change in attitude (roll, pitch, yaw tilt position in space) and perceived angular velocity in space that was not reflected by parallel changes in the plane or magnitude of the VOR. This series of experiments establishes several facts concerning spatial orientation perception beyond the predictive domain of any current model. New concepts are needed and several are suggested to deal with changing reactions to complex combinations of linear and angular accelerations.
