Conservation development in blind children.
D000367:Age Factors; D001766:Blindness / Q000151:congenital*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D006801:Humans; D011582:Psychological Theory; D013028:Space Perception; D014785:Vision, Ocular; D014892:Weight Perception