The conceptual categories that children have developed in their second year were studied in five experiments using object manipulation tasks. Subjects included 152 children from 18 to 31 months of age. These very young children had formed global conceptions of many domains of objects. (SLD)

Six experiments involving 262 children (as young as 16 months and as old as fifth grade) indicate that the basic framework for coding location is present early in life and that later development consists of an increasing ability to impose organization on a broad range of bounded spaces. (SLD)