Optical information for detecting loss in one's own forward speed.
An experiment was conducted to determine whether accuracy and efficiency of detecting loss in one's own forward speed are constant when optical information is invariant over a wide range of environmental variables. Deceleration rate, initial forward velocity, and altitude were varied so as to isolate initial optical flow rate, optical flow deceleration, and optical flow damping invariants specified in observer-relevant metrics. The candidate resulting in the most consistent effect on performance was global damping, which specifies a contrast of flow deceleration with initial flow rate. The finding is a first step toward validating a procedure for identifying functional invariants by assessing the usefulness of mathematically specified optical information for the perception of egomotion. The research represents both a methodological development and empirical support for the broader program of ecological functionalism.
D000054:Acceleration; D000531:Altitude; D003201:Computers; D003654:Deceleration; D004192:Discrimination, Psychological; D006801:Humans; D007699:Kinesthesis; D014796:Visual Perception