title: Covert reinforcement: two studies and a comment.
mesh_terms: D000328:Adult; D001521:Behavior Therapy; D003216:Conditioning, Operant; D003463:Cues; D005260:Female; D006801:Humans; D007092:Imagination; D008297:Male; D008875:Middle Aged; D012054:Reinforcement, Psychology; D012559:Schizophrenia / Q000534:rehabilitation*; D012737:Sex Factors