Two socially isolated patients were placed on a program where social reinforcement from staff members was made dependent on social interaction with other patients or staff members. This procedure was imposed in a setting where only limited control was possible. The level of social interaction and a concomitant alternate behavior in each patient was increased when the contingency for social reinforcement was imposed. The study provides another example of the efficacy of social reinforcement where there is little control over other reinforcers. Implications for use of similar procedures to increase generalization in the community are discussed.Many recent studies of operant conditioning treatment for severe psychological disorders have made use of tokens that could be used to purchase meals, beds, and other events and have been conducted on wards where much control was possible (Ayllon and Azrin, 1965;Ayllon and Azrin, 1969;Ayllon and Haughton, 1962). However, initial efforts at operant conditioning treatment made effective use of social reinforcement (Ayllon and Michael, 1959), and more recently, the ubiquity of unscheduled social reinforcement has been implicated as a powerful source of reinforcement for maladaptive behavior in the typical psychiatric hospital (Gelfand, Gelfand, and Dobson, 1967 2The investigator wishes to thank the members of the psychiatric treatment teams on ward 8-S for their cooperation and specifically Messrs. Crawford, Brown, Rivers, Sims, Stevenson, Tucker, and White, without whose efforts this study would have been impossible.