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The role of stimuli in chained fixed‐ratio schedules of reinforcement was examined. At various ratio values, responding on schedules consisting of three or five equal components, with a different colored light in each component (“block counter”) was compared with responding on tandem or simple fixed‐ratio schedules having the same color present throughout the entire ratio. At all ratio values except the smallest, the chain stimuli resulted in longer pauses after reinforcement. The magnitude of this effect became greater as the size of the ratio was increased. Post‐reinforcement pause durations were longer under five‐component schedules than under three‐component schedules. Running rates in the first component were lower on the chained schedules than on the tandem schedules; on both kinds of schedule, rates were lower in the first component than in the rest of the ratio. When the sequence of stimuli was reversed, the duration of the post‐reinforcement pause dropped markedly and the running rate in the initial component increased, but these effects gradually disappeared after the first reversal session. When the final chain stimulus was substituted for the first component stimulus but continued to appear in the final chain component as well, the pause duration dropped and remained at this lower level during subsequent sessions.

The effects of extinction and of response‐independent (free) reinforcement in decreasing rates of key pecking by pigeons were compared in single schedule (Phase 1) and multiple (Phase 2) conditions. In both phases, response rates decreased more rapidly with extinction than with free reinforcement conditions. Behavioral contrast was obtained from subjects trained in a multiple schedule involving extinction in Phase 2, whereas subjects trained in a multiple schedule involving free reinforcement showed a slight negative induction effect. Whether subjects experienced extinction or free reinforcement under single stimulus conditions did not affect subsequent performance in the discrimination situation of the second phase. Disinhibition testing was carried out at the end of both phases, but there was no evidence for disinhibitory effects under any condition.

Albino rats were conditioned to lever press during two‐component multiple and mixed schedules in which response‐dependent and response‐independent reinforcers occurred in the different components. Relative response rates in the components associated with response‐dependent reinforcers were higher (a) when different visual and auditory stimuli were associated with the two components and (b) when mixed schedule components were long in duration. These results illustrate the contribution of the response‐reinforcer relation to stimulus control and schedule control of behavior. They also suggest that under some conditions, reinforcers need not be consistently associated with a particular response to ensure that the response is maintained at a relatively high rate.

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Different ways of modifying the aide‐patient relationship to promote improvement in psychiatric patients were investigated. Psychiatric aides were given information about the behavior of assigned patients, cash awards based on the improvement of assigned patients, and different kinds of supervision by the psychology staff; the effects of these variables on a large number of psychiatrically relevant behaviors were measured. Appropriate behavior of patients increased when the aides were given quantitative information about the improvement of assigned patients. Cash awards for aides, which were not contingent on the behavior of patients had little effect, while cash awards contingent on the behavior of assigned patients were associated with more appropriate behavior. Direct supervision of aide‐patient interactions was associated with an increase in appropriate behavior, while required consultation for the aides about assigned patients was not. Behavior of patients deteriorated when the program was terminated.

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