Retinal Size in the Visual Cliff Situation

Abstract

300 one-day-old chicks were used in two experiments. Exp. I was designed to test an hypothesis that unequal retinal size is an insufficient cue for depth discrimination in a visual cliff situation. One group of Ss was exposed to mirrors on deep and shallow sides which reflected only their image and a white ceiling. A second group was exposed to white patterns, and a third to stripe patterns equated for retinal size. No significant preferences were found. No conclusions were made regarding the cue of unequal retinal size. In Exp. II, motion parallax was maximized by the use of three-dimensional patterns. One group was exposed to 3-D patterns equated for retinal size, a second to 2-D patterns unequated, and a third to 3-D patterns unequated. A significant preference for the shallow side was found only for the first group. Results of both experiments suggested that the total size of the pattern areas was too small to permit consistent depth discrimination. Implications for studies attempting to define thresholds were discussed.