Children's understanding of negation as a logical operation.
D000367:Age Factors; D000704:Analysis of Variance; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D003116:Color; D005260:Female; D006801:Humans; D007802:Language; D008128:Logic; D008297:Male; D012737:Sex Factors; D012959:Socioeconomic Factors