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To determine the effect of a negative discriminative stimulus on the response producing it, two pigeons were each studied in a three‐key conditioning chamber. During alternating periods of unpredictable duration, pecking the center (food) key either was reinforced with grain on a variable‐interval schedule or was never reinforced. On equal but independent variable‐interval schedules, pecking either of the side (observing) keys changed the color of all keys for 30 sec from yellow to either green or red. When the schedule on the center key was variable‐interval reinforcement, the color was green (positive discriminative stimulus); when no reinforcements were scheduled, the color was red (negative discriminative stimulus). Since pecking the side keys did not affect grain deliveries, changes in the rate of pecking could not be ascribed to changes in the frequency of primary reinforcement. In subsequent sessions, red was withheld as one of the possible consequences of pecking a given side key. When red was omitted, the rate on that key increased, and when red was restored, the rate decreased. It was concluded that red illumination of the keys, the negative discriminative stimulus, had a suppressive effect on the response that produced it.

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Eight preschool children were exposed initially to an unstructured (open) classroom in which, among other objects, a dozen different books were continuously available. Samples of the subjects' behavior over several weeks documented a very low frequency of reading‐related activity (attention to books). Introduction of novel books into the classroom increased some children's reading‐related behavior, but adults who modelled reading by reading aloud produced larger and more stable increases of such behavior. There was also a relative increase in frequency of independent and a relative decrease in mutual‐peer reading‐related activity, possibly as a result of modelling. The study calls attention to the need to evaluate the open‐classroom setting in a manner compatible with the experimental analysis of behavior in other applied settings—a manner that is also consistent with the real aims of open education.

It is presumed that recreation activities have a variety of functions for people, from tension reduction to citizenship development; however, a recreation activity's most empirically obvious function is as a reinforcer. This study demonstrates how two recurrent problems of urban recreation programs—recruitment of members and reduction of disruptive behaviors within the program—can be handled simply by contingently adjusting the amount of time the recreation activities are available. When extra time in the recreation center was provided to those youths who brought new members, dramatic increases in membership were achieved. On the other hand, when the closing time for each evening's recreation program was publicly moved forward by a few minutes for each offense, disruptive behaviors were nearly eliminated. Recreation used as a reinforcer can thus improve the basic operation of a recreation center and might similarly enhance other presumed and desired functions of recreation.

Aggressive and self‐injurious behaviors of four retarded children were reduced by combining various techniques with the differential reinforcement of other behaviors (DRO). In one study, aggressive responses of a severely retarded child were reduced when DRO was combined with a 30‐sec timeout. In a second study, various aggressive classroom behaviors were reduced when the child was told “no” for an inappropriate response but earned puzzle pieces for periods of time when inappropriate responses did not occur. Exchangeable tokens were given to a third subject for every 15 min in which aggressive responding did not occur, while each inappropriate response resulted in the loss of all tokens accrued. Responding was decreased to a level far below baseline. For a fourth child, self‐injurious responses were followed by “no”, and intervals of time in which no self‐injurious responding occurred earned candy. The rate of this behavior reduced significantly. In each case, the DRO procedure combined with the other techniques proved to be manageable for the teacher and successful in reducing the inappropriate behavior.

Four groups of six pigeons each were given nondifferential training on multiple variable‐interval variable‐interval reinforcement schedules and then were switched to differential training involving a multiple schedule in which reinforcement density was reduced in one of the two components. The multiple schedules used in the four groups had mean interreinforcement intervals of 1 min and 1 min in the two components changed to 1 min, 5 min; 2.5 min, 2.5 min changed to 2.5 min, 5 min; 12 sec, 12 sec changed to 12 sec, 24 sec; and 12 sec, 12 sec changed to 12 sec, 60 sec. In subsequently administered wavelength generalization tests, some peak shifts were observed in each condition and occurred occasionally in the absence of behavioral contrast or rate reduction in the less‐reinforced component. The best predictor of peak shift was a high proportion of total responses emitted during the more‐reinforced component at the end of differential training.

Response‐cost procedures within a token economy with extremely regressed residents excluded many residents from access to positive reinforcement. Procedures allowing residents to “purchase eligibility” to obtain backup reinforcers through contingent payment on standing fines, combined with proportional fine payoff schedules contingent upon time without new fines, increased payment on fines, reduced incidence of new fines, and increased utilization of backup reinforcers. These modifications removed adverse side effects while retaining the benefits associated with response costs. Failures or adverse effects of elements of token systems should not occasion abandonment of token economies, but rather encourage their continual evaluation and modification.