Convergence as a cue to perceived size and distance

A wire mesh was used as stimulus object in the old ‘wall-paper experiment’. Fixating a small object on the near side of the wire mesh, the mesh appears of course double. By adjusting the fixation object back and forth a position can be reached at which fusion of the double image is obtained. At this moment the wire mesh appears to shift location. A nearly perfect one-to-one correspondence obtained between the perceived distance of the ‘fused.’ wire mesh and the actual convergence distance. It is concluded that the convergence mechanism may provide perfectly specific information to the visual system concerning the spatial location of objects.