title: Two-year gains in reasoning by retarded and nonretarded persons.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002657:Child Development; D003071:Cognition; D005260:Female; D006801:Humans; D008607:Intellectual Disability; D007361:Intelligence Tests; D008297:Male; D011581:Psychological Tests; D011582:Psychological Theory; D013850:Thinking