A series of six experiments, involving 198 subjects, examined the hypothesis that delinquents are less responsive than non-delinquents to social reinforcement and punishment. The hypothesis received support (a) using two different experimental techniques, one in which the subjects' judgements of autokinetic movement were modified and one using the Taffel (1955) verbal conditioning paradigm; (b) with the female adult administering the reinforcement and with a peer; (c) when the contingent social cues were rewarding (Good or Fine) and when they were punishing ('No'). The hypothesis was not supported when the verbal reinforcement was varied. Control studies using no reinforcement and money reinforcement indicated that the social reinforcement did indeed have a specific reinforcement effect and that delinquents did not show a general learning deficiency.