The Illusory Perception of Movement Caused by Angular Acceleration and by Centrifugal Force During Flight. II. Visually Perceived Movement of a Fixed Target During Turns

摘要

The oculo-gyral and oculo-gravic illusions were studied in flight using three trained subjects who observed a fixed luminous target in the dark. All observations were made in the rear cockpit of a standard Navy training plane. The subject gave a running account of the apparent motion and displacement of the target while the pilot maneuvered the plane through different degrees of bank. All of the observers' reports and the pilot's signals were recorded on an airborne wire recorder and written transcriptions of these recordings were made in the laboratory. These written protocols served as a basis for the analyses of the data. The results show that illusions of motion and displacement may occur during all degrees of bank for 10 to 60 degrees, and always occurred during banks of 40 degrees and above. There is a direct relation between the degree of bank and the amount of motion and displacement observed; the maximum observed displacement of the star from the 'true' position was 50 degrees. All displacements were observed in or close to the vertical plane whereas motion was observed not only upward and downward but to the right and left.