Two experiments tested the effects of crawling-onset age, amount of crawling experience, and testing age on avoidance of the deep side of a visual cliff apparatus by human infants. Crawling-onset age disciminated between infants because crawling during the tactile phase interferes with later visual control of locomotion. (Author/RD)

Examined perception of object unity in partial occlusion in 72 infants. Recorded how long subjects looked at a display of complete and incomplete rods. In test and control conditions, infants looked longer at broken rods than at complete rods, suggesting that infants' cognitive, visual, or attentional skills may be insufficient to support…