title: Effects of partial reward on lever pulling and activity level of retarded youth.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003216:Conditioning, Operant; D005260:Female; D005639:Frustration; D006801:Humans; D008607:Intellectual Disability; D008297:Male; D009043:Motor Activity; D012201:Reward; D012737:Sex Factors