title: Demonstration versus instructions in concept attainment by mental retardates.
mesh_terms: D000293:Adolescent; D000328:Adult; D003210:Concept Formation; D004495:Education of Persons with Intellectual Disabilities; D005246:Feedback; D005260:Female; D006801:Humans; D007100:Imitative Behavior; D008297:Male; D012201:Reward; D014163:Transfer, Psychology; D014705:Verbal Behavior