A study of the development of conservation by a nonverbal method.
D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D005260:Female; D006801:Humans; D008128:Logic; D008297:Male; D012737:Sex Factors; D013850:Thinking; D014705:Verbal Behavior; D014796:Visual Perception