THE SPIRAL AFTEREFFECT: II. INFLUENCES OF VISUAL ANGLE AND RETINAL SPEED ON THE DURATION AND INTENSITY OF ILLUSORY MOTION,

Visual illusions have been a persistent problem in aviation research. The spiral aftereffect SAE is an example of one type of visual illusion--that which occurs following the cessation of real motion. Duration and intensity of the SAE was evaluated under five conditions. Results indicate that perceived rather than physical characteristics of the stimulus situation may have the most significant effects on duration of the SAE. The findings thus have considerable pertinence to the evaluation of effective factors in the production of a variety of other visual illusions which can occur in aviation environments. Author