Motion displacement thresholds for compound stimuli predicted by the displacement of centroids.

ABSTRACT

Minimum displacement thresholds were measured using a compound motion stimulus, in which a single bar split into oppositely moving components, having different luminances and absolute displacements. The results fit a simple model in which observers detect the movement of the centroid of the combined luminance pattern of the two components. This was so even when the two components were separated by more than the static spatial resolution limit of 30 sec arc.