2 FORMS OF RETINAL DISPARITY

The retinal disparities in stereograms where the vertical alignment of pairs of homologous points in 1 eye [in man] differs from that in the other eye were more effective than disparities that do not involve that kind of binocular difference. The presence of such transverse disparities shortened the time elapsed until perceived depth was reported in 4 instances, in 2 simple stereogram pairs and in 2 different pairs of random dot pattern stereograms. In an experiment where binocular parallax was in conflict with an effect of past experience, the presence of transverse disparities caused binocular parallax to prevail. The presumption that the amount of perceived depth depends only on the amount of disparity (provided distances from the eyes are unchanged) and not on the configuration in which it manifests itself did not hold in stereograms containing transverse disparities.