The Magnitude of the Pulfrich Stereophenomenon as a Function of Binocular Intensity Differences at Various Levels of Illumination.

摘要

This investigation is concerned with a stereophenomenon first described and analysed by Pulfrich: with unequal illuminations in the two eyes, the bob of an oscillating plane pendulum appears to rotate out of its plane of oscillation. The apparent displacement has been accounted for in terms of differences in visual latent periods for the two eyes. Appropriate theory allows for calculation of latency differences when the apparent displacement of the oscillating object in the vertical median plane is determined. Determinations are made of the relationships existing between (1) the magnitude of the near and far displacements (or the corresponding calculated latency differences) and (2) the difference in retinal illumination existing between the two eyes for (3) many basic levels of illumination. The results obtained may be accounted for on the assumption that the absolute visual latent period and the logarithm of the stimulus intensity are inversely related. The results are analyzed in terms of the laws of space perception, and additional experiments have been performed to test the relations.