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The fixed‐ratio requirement was varied in concurrent fixed‐interval fixed‐ratio schedules. Fixed‐interval responding was reinforced by food. In different phases, fixed‐ratio responding was reinforced by food or water. There was a direct relation between the ratio requirement and interval response rates when both responses were reinforced with food, but essentially no relation when the reinforcers were different. The role of reinforcers in concurrent schedules merits detailed study.

The study compared the behavior of family members at home as recorded by audiotape recordings in two conditions: with an observer present or absent. Behavioral differences were expected as a function of differential reactivity to these observational procedures, but none was found, and there was no evidence of adaptation effects in either condition. In general, significant positive correlations were obtained between the rates of recorded behavior in both situations. The implications of these findings for the development of nonreactive observation procedures were discussed.

A matching paradigm was used to examine the discriminative properties of two different reinforcement contingencies. Responding according to either a differential‐reinforcement‐of‐low‐rate or a differential‐reinforcement‐of‐other‐behavior schedule produced a choice situation in which each of two keys was illuminated with a unique color. The correct choice response was defined by the contingency that was met to produce the choice. Eighty to 100% correct matching was obtained and recovered during two reversals of the choice stimuli. Introduction of a delay between completion of the reinforcement contingency and presentation of the choice stimuli resulted in decrements in matching performances similar to those obtained when other types of sample stimuli are used. The results provided evidence of the discriminative properties of the relation between behavior and other classes of stimuli.

Temporal patterns of key pecking by pigeons were shaped by a schedule in which the delivery of food was contingent upon a measure of the overall extent to which the temporal pattern of behavior within a 5‐sec trial conformed to a required pattern. This pattern approximated a constant rate of change in the rate of key pecking throughout the 5‐sec trial. In comparison with behavior maintained by a classical fixed‐interval 5‐sec schedule, the new schedule controlled a better approximation to a “scallop” within individual trials and greatly reduced intersubject variability. These results are consistent with the view that the delivery of a reinforcer after a behavioral pattern a few seconds in duration may strengthen the entire pattern as a unit, or operant. The response topography contiguous with reinforcement may be a negligible fraction of the strengthened operant. One implication of this view is that mean response rate for such brief responses as key pecks and lever presses is a byproduct of whatever patterns are strengthened, and generally will not reveal fundamental controlling relationships, whenever a reinforcer is not contiguous with all the behavior on which it is contingent.

Pigeons obtained food by making four responses on three keys in a specified sequence, e.g., left, right, center, right. Under the “tandem‐learning” condition, all three keys were the same color throughout the response sequence, and the sequence was changed from session to session. After total errors per session (overall accuracy) and within‐session error reduction (learning) had stabilized, the effects of varying doses of phenobarbital and chlordiazepoxide were assessed. For comparison, the drug tests were also conducted under a “performance” condition, in which the response sequence was the same from session to session, and under corresponding “chain‐learning” and “chain‐performance” conditions, where different colored keylights were associated with the response sequence. Under all four baseline conditions, the largest dose of each drug impaired overall accuracy. Under the two learning conditions, the error rate decreased across trials within each session, but the degree of negative acceleration was less in the drug sessions than in the control sessions. In contrast, under the two performance conditions, the error rate was relatively constant across trials, but was higher in the drug sessions than in the control sessions. Of the four baselines, the chain‐learning condition was the most sensitive to the drug effects.

Attempting to replicate procedures from Achievement Place, token reinforcement procedures were used to modify savings, conversational interruptions, and table‐setting of delinquent boys residing in a home‐style, community based, treatment setting. The tokens (points) were redeemable for various privileges and could be earned for specified appropriate behaviors and lost for specified inappropriate behaviors. Contingent point fines reduced the frequency of interruptions. Point rewards improved table‐setting, but even large point rewards did not substantially increase savings. Baseline data indicated that lateness to dinner was not a problem, as it was in Achievement Place. Withdrawal of contingent points and back‐up rewards did not disrupt the clean‐up behavior of two boys.

Three experiments examined the effects of superimposing free reinforcement (Free VI 30‐sec) on behavior maintained by a response dependent mult VI 2‐min VI 2‐min schedule of reinforcement. Experiment I used pigeons as subjects, key pecking as the response, and colors of response key as the stimuli associated with the multiple‐schedule components. When free reinforcement was added during only one component (Differential condition) a large and highly significant increase in response rate developed in this component. Adding free reinforcement during both components (Nondifferential condition) produced smaller and far less‐consistent effects. An entirely different pattern of results was obtained in two subsequent experiments, where similar procedures and reinforcement conditions were used with rats as subjects and bar pressing as the response. In both Experiments II and III, response rates decreased to the stimulus associated with added free reinforcement in the Differential condition. These findings are interpreted as the result of interactions between behavior maintained by response‐reinforcer contingencies and behavior maintained by stimulus‐reinforcer contingencies. As such, they support the main assumption of an auto‐shaping theory of behavioral contrast, that additivity of responding generated by the two kinds of contingency can occur only in situations favorable to autoshaping.

Four rhesus monkeys were tested for preferences within the wavelength and line‐tilt dimensions. In the case of wavelength, the response panel was back‐illuminated by light of one of the following wavelengths, presented in a random manner: 470, 525, 580, and 635 nm. Similarly, the line‐tilt dimension was studied, by presenting a 5 cm by 0.3 cm black bar tilted at 0, 30, 60, or 90 degrees. No preferences were found within this latter dimension; in contrast, marked wavelength preferences existed, the order of preference being 470 (most preferred), 525, 580, and 635 nm (least preferred). These response preferences were resistant to behavioral manipulation; the number of responses to blue and to red in extinction was about equal when red was used as the training stimulus, but vastly different following training on blue. These results indicate that such response preferences must be taken into account in the design of a wide variety of experiments.

Three pigeons key pecked under second‐order schedules in which the completion of two successive fixed‐ratio 50 components constituted a reinforcement cycle. Tandem, chained, and brief‐stimulus second‐order schedules were studied when completion of the initial fixed‐ratio 50 component delivered brief intense electric shock in every nth reinforcement cycle and n assumed values between one and nine. During sessions without shock, the brief‐stimulus (unpaired with food) schedule generated higher rates of responding in the initial component than did the tandem schedule. Electric shock engendered increased time to the fifth response and a repeated pause‐run pattern of not responding and responding, particularly in the initial component, even with shock scheduled in every ninth reinforcement cycle. The results were consistent with those reported for shock of a shorter duration scheduled in every reinforcement cycle. The overall rate of responding decreased as a function of increasing shock density and was lower in brief‐stimulus than in tandem schedules.

In a two‐key chamber, one key (the food key) was either red or green with different variable‐interval schedules operating concurrently in each color and a second key (the changeover key) served to change the food‐key color. Three pigeons were trained with either a 2‐sec changeover delay or a 0‐sec changeover delay and three birds with a fixed‐ratio 2 on the changeover key instead of a changeover delay. The proportion of time spent in red approximated the proportion of reinforcers delivered in red for all birds. When the procedure was changed so that reinforcers were signalled in the green schedule, rates of reinforcement were unaltered, but the pigeons spent virtually the whole session in red. Changeovers to green were allowed only when a reinforcer was assigned by the schedule associated with green. For all pigeons with the fixed—ratio requirement on the changeover key or with a 0‐sec changeover delay, the overall rate of red‐key responses was higher during the signalling condition than during unsignalled, or baseline, condition. The present data question the generality of previous reports that the rate of one response is independent of the amount of time allocated to the alternative response.