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The acquisition and maintenance by rats of single alternation, double alternation, and four other repeating patterns of reinforced and non‐reinforced trials was studied in a discrete‐trial lever‐pressing situation. The rats learned all these patterns in a small number of experimental sessions. Single alternation was learned more rapidly than the more complex patterns. Rate of learning single and double alternation decreased moderately as inter‐trial interval increased. Abrupt changes in the scheduling of trials, either by doubling the inter‐trial interval or by shifting from fixed to variable trial spacing, temporarily disrupted the patterned performance. Two hypotheses concerned with the means by which the rats could have learned to conform to the pattern were examined: (1) “timing” of the interval between successive reinforcements; and (2) control of responding on a trial by the outcome of preceding trials, depending on the consistency with which these outcomes were associated with reinforced or non‐reinforced trials in the pattern and on how many trials back these outcomes occurred. The second hypothesis accounted for the relative frequency of errors on trials at various locations in the sequences, and predicted most of the changes in error frequency observed in experiments in which “inter‐trial stimuli” were added to the sequences.

Performance on associated mixed and multiple variable‐interval—extinction schedules was studied as a function of food versus intracranial stimulation (ICS) reinforcement. For the mixed schedule, differential responding was greater for an ICS reinforcement group than for a food reinforcement group, demonstrating that conditions affecting resistance to extinction help to determine the control exerted by a mixed schedule. Performance on the multiple schedule demonstrated greater differential responding for an ICS group than for a food reinforcement group during the early training sessions, indicating that the control exerted by mixed schedules interacts with that exerted by the exteroceptive discriminative stimuli. The results suggest that the influence of the associated mixed schedule on discriminative responding would be greater, the greater the difficulty of the stimulus discrimination.

The responding of rats was reinforced on one key after a 1‐sec auditory stimulus and on a second key after a 5‐sec stimulus. With errors punished by a short timeout, all subjects achieved a high level of accuracy. A chain of responses during the stimuli mediated the performance so that when the auditory signals were omitted accuracy decreased only slightly. Response‐independent aversive stimulation superimposed upon this procedure both suppressed the total amount of behavior and reduced the accuracy of the discriminative performance, the intensity of the stimulus determining the error rate. The increase in errors under these conditions may have depended in part upon differential suppression of members of the response chain, but such suppression was not necessary, since error rate increased even in its absence. Furthermore, the locus of response disruption within the chain was not consistent from day to day either for any individual animal or across animals.

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The first study investigated a group control procedure for suppression of excessive sound‐intensity levels in a regular public school classroom. Reinforcement consisted of a 2‐min addition to the class gym period and a 2‐min break after maintenance of an unbroken 10‐min quiet period as monitored on a decibel meter. Transgressions of the sound limit (42 decibels) resulted in a delay of reinforcement by the resetting of the timer to the full 10‐min interval. The results indicated that these procedures were highly effective in suppression and control of sound intensities. The second experiment utilized a similar procedure coupled with a procedure of eliminating out‐of‐seat behavior. Experiment III studied the effects of Exp. II procedures on a single student's out‐of‐seat behavior rate. All procedures were found effective.

In three experiments, human subjects were trained on a five‐component multiple schedule with different fixed intervals of monetary reinforcement scheduled in the different components. Subjects uninstructed about the fixed‐interval schedules manifested high and generally equivalent rates regardless of the particular component. By comparison, subjects given instructions about the schedules showed orderly progressions of rates and temporal patterning as a function of the interreinforcement intervals, particularly when feedback about reinforcement was delivered but also when reinforcement‐feedback was withheld. Administration of the instructions‐reinforcement combination to subjects who had already developed poorly differentiated behavior, however, did not make their behavior substantially better differentiated. When cost was imposed for responding, both instructed and uninstructed subjects showed low and differentiated rates regardless of their prior histories. It was concluded that instructions can have major influences on the establishment and maintenance of human operant behavior.

Two severely retarded boys, each a member of a different play group, experienced three regimes of reinforcement from adults [contingent, noncontingent, and mixed (contingent and noncontingent)]. The agent of contingent reinforcement acquired stimulus control of the subjects' behavior; the noncontingent agent did not. The agent of the mixed schedule of reinforcement did not gain control, but aspects of his behavior came to function as cues. The mixed adult's withholding reinforcement in the absence of the target behavior (cooperative play) evoked cooperative play, whereas his presenting free reinforcement resulted in the subjects' remaining in their inactive, baseline positions.

In concurrent, two‐member chains, the completion of one or the other of two initial percentage fixed‐interval 90‐sec links produced a terminal link in which the completion of a fixed ratio produced food reinforcement. The fixed ratios and the duration of reinforcement in the terminal links were varied. Relative response rate in initial links was proportional to the relative reinforcement duration per ratio response (reinforcement duration divided by fixed ratio) in terminal links. The rate of responding in the terminal fixed‐ratio links was insensitive to both ratio size and reinforcement duration and therefore did not vary sufficiently to distinguish between responses per reinforcement and immediacy of reinforcement as controlling variables in terminal links.