An evaluation of quantity conservation performance during old age.
D000368:Aged; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology; D004522:Educational Status; D005260:Female; D006801:Humans; D008297:Male; D008606:Mental Processes; D008875:Middle Aged; D011581:Psychological Tests; D011582:Psychological Theory; D012737:Sex Factors