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Pigeons were trained to peck at red or green keys presented simultaneously in discrete trials. In one experiment, reinforcements were arranged by concurrent variable‐interval schedules. The proportion of responses to green approximately matched the proportion of reinforcements produced by pecking green. Detailed analysis of responding revealed a systematic decrease in the probability of switching from green to red within sequences of trials after reinforcement. This trend corresponded to sequential changes in the relative frequency of reinforcement, and not to sequential changes in probability of reinforcement. In a second experiment, reinforcements were scheduled probabilistically every seventh trial. Even though there were no contingencies on pecking during the first six post‐reinforcement trials, choices of green on the first response after reinforcement matched the proportion of reinforcements for pecking green. These results extend the generality of overall matching under concurrent reinforcement.

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The study attempted to isolate some of the environmental conditions that controlled the self‐destructive behavior of three severely retarded and psychotic children. In the extinction study subjects were placed in a room where they were allowed to hurt themselves, isolated from interpersonal contact. They eventually ceased to hurt themselves in that situation, the rate of self‐destruction falling gradually over successive days. In the punishment study, subjects were administered painful electric shock contingent on the self‐destructive behavior. (1) The self‐destructive behavior was immediately suppressed. (2) The behavior recurred when shock was removed. (3) The suppression was selective, both across physical locales and interpersonal situations, as a function of the presence of shock. (4) Generalized effects on other, non‐shock behaviors, appeared in a clinically desirable direction. Finally, a study was reported where self‐destructive behavior increased when certain social attentions were given contingent upon that behavior.

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Brief timeout for disruptive and aggressive behaviors and reinforcement for appropriate behaviors were used with two retarded patients in a state hospital ward setting. The procedures reduced loud vocal behavior in one patient and aggressive behavior in another to near‐zero levels when first applied. The behaviors returned to previous levels when the procedures were removed and were again greatly reduced when timeout and reinforcement were reapplied. The results were significant because the behavior problems were severe and long‐standing and the procedures were instituted without greatly disturbing normal ward routine.

The present experiment was designed to test the efficacy of symbolic modeling as a treatment to enhance social behavior in preschool isolates. Nursery school children who displayed marked social withdrawal were assigned to one of two conditions. One group observed a film depicting increasingly more active social interactions between children with positive consequences ensuing in each scene, while a narrative soundtrack emphasized the appropriate behavior of the models. A control group observed a film that contained no social interaction. Control children displayed no change in withdrawal behavior, whereas those who had the benefit of symbolic modeling increased their level of social interaction to that of non‐isolate nursery school children.

Pigeons were exposed to four cycles per session of a multiple schedule in which each cycle involved twelve 60‐sec fixed intervals followed by four 180‐sec intervals [(12 FI 60‐sec)(4 FI 180‐sec) schedule]. Post‐reinforcement pauses were shorter during the first few short intervals of each cycle than during later short intervals, and increased over the four long intervals of each cycle (positive and negative transient contrast). A (12 FI 15‐sec)(4 FI 45‐sec) schedule showed similar results. These two schedules differed in some other respects indicating effects of absolute FI duration on stimulus control. Differences in contrast properties between both these procedures and multiple variable‐interval schedules were related to the pause‐producing property of reinforcement on FI (temporal inhibition). Behavior under two other multiple fixed‐interval schedules—(2 FI 360‐sec)(1 FI 720‐sec) and (3 FI 360‐sec)(1 FI 720‐sec)—differed in certain respects from both the (12 FI x‐sec)(4 FI 3x‐sec) schedules. These differences may be related to differences in the number of successive fixed intervals within a component (run length).

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