Plan view of a pendulum swinging in a plane (solid black) that appears to swing in an ellipse (dashed black) when one eye views it through a neutral-density filter – A denotes the actual position of the bob, A′ its previous position (as perceived by the darkened eye) and A* its apparent position; similarly for B and C
The Pulfrich effect is a psychophysicalpercept wherein lateral motion of an object in the field of view is interpreted by the visual cortex as having a depth component, due to a relative difference in signal timings between the two eyes.
