Direction and frequency specific processing in the perception of long-range apparent movement.

The presentation of repetitive apparent movement (AM) produces the illusion of smooth sinusoidal movement. During prolonged observation this impression vanishes periodically. On the basis of these observations, it was postulated that such long-range AM are processed via direction and frequency specific subsystems. This hypothesis was examined by means of selective adaptation. A bi-stable movement display was used to measure the adaptation effect. Generally a frequency specific reaction for horizontal and vertical movement was verifiable. In addition to this, the existence of the presumed narrow-band processing channels was confirmed by the tuning curves determined. The significance of the results for AM perception and their applicability to the processing of real movement Gestalt will be discussed.