Boston University Center for Adaptive Systems and Department of Cognitive and Neural Systems
Abstract
How is the perceived direction of motion of a target affected by the motion of multiple surrounding regions? Observers viewed displays consisting of three nested regions, a circular target region surrounded by two concentric annuli, each containing coherently moving dots. The observers' task was to estimate the direction of motion of the dots in the central region. By itself, motion in either annulus can alter this estimate, producing a contrast effect whereby the perceived direction of the centre is biased away from the direction of motion of the annulus. In combination, the outer annulus dominated the inner in its effect on the target's motion. This result suggests that local operators, such as antagonistic centre-surround mechanisms for motion direction, are in themselves insufficient to explain relative motion effects.Office of Naval Research (N00014-92-J-4015, N00014-91-J-4100, N00014-94-J-0597); National Science Foundation (IRI- 90-00530); Air Force Office of Scientific Research (F49620-92-J-0334
