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Two experiments investigated the extent to which response contingencies influence the choice between two schedules of reinforcement by exposing pigeons to a concurrent‐chains procedure in which reinforcers in one terminal link were response‐independent, and in the other terminal link, response‐dependent. In Experiment 1, the pigeons were indifferent between an aperiodic, response‐independent schedule and an aperiodic, response‐dependent schedule that required a minimum rate of responding. This finding limits the generality of a required‐rate contingency as a determinant of choice, which contingency had been previously demonstrated in a context of periodic reinforcement to evoke preference for an alternate schedule. In Experiment 2, the pigeons preferred a periodic, response‐independent schedule to a periodic, response‐dependent schedule that shared a feature with a required‐rate schedule: there was a requirement to respond early in the interreinforcement interval, when responding produced reinforcement only later. The results of the two experiments suggest the following general interpretation: pigeons prefer a second schedule to the extent that the response contingencies of the first schedule must be satisfied during discriminable periods of nonreinforcement.

Choice between a signalled shock schedule and an unsignalled one was examined at various shock intensities. Three rats were given the opportunity to change from the unsignalled schedule to the signalled one at intensity values between 0.15 mA and 1.0 mA. Steps were usually 0.15 mA and both ascending and descending series were given. For two other rats, shock intensity increased from 0.20 mA to 1.0 mA in 0.20‐mA increments; for two additional rats, shock intensity was first 3.0 mA and was then reduced to 1.0 mA. Subjects tended to remain in the unsignalled schedule at the lower shock intensities, but spent most of each session under the signalled schedule at the higher intensities (1.0 mA and 3.0 mA). In addition, the time spent in the signalled schedule tended to vary systematically with shock intensity over at least part of the range of intensity values. It was concluded that the relationship between shock intensity and choice behavior is similar to the relationship between intensity and behavior in procedures involving avoidance, escape, and punishment.

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In studies of stimulus compounding (1) the stimuli are presented randomly, (2) primary reinforcement is correlated with each stimulus, (3) a specific response is emitted during each stimulus, and (4) the response is necessary to produce the reinforcer. The present experiments assessed the importance of these procedures by (1) presenting light and tone stimuli in fixed order, (2) removing reinforcement (food) during one stimulus, (3) preventing the response (lever pressing) from being emitted, and (4) eliminating the contingency between lever pressing and food. These variables were presented in various combinations within the context of chained and multiple schedules. When the stimuli were combined in the schedule component correlated with each stimulus, the frequency of lever pressing increased in most instances (additive summation). This suggests that the effect of combining stimuli was not closely tied to the specific procedures used in previous experiments. However, presenting the stimuli in a fixed order did have an effect: the level of responding to the compound was generally greatest when the stimuli were combined in the component correlated with the higher frequency of lever pressing to the single stimulus. Additive summation failed to occur consistently when response‐independent food was correlated with each stimulus, and when both lever pressing and food were eliminated during one stimulus.

Two chinchillas were trained on a series of two‐valued auditory intensity discriminations. Lever presses were reinforced when no tone was present and not reinforced in the presence of a four‐kiloHertz tone. The intensity of the nonreinforced tone was successively decreased, increasing the difficulty of the discrimination, until differential responding resembled that on a mixed schedule (no‐tone‐no‐tone). Response data were partitioned in such a way as to provide a continuing assessment of the relative amounts of control exerted by the reinforcement schedule and the sound intensity, respectively. Control by reinforcement density was a direct function of discrimination difficulty, whereas the control exerted by intensity was inversely related to difficulty. For these chinchillas, the absolute threshold value obtained at four kiloHertz was about two decibels referenced to 20 microNewtons per meter squared.

Responses on one key (the main key) of a two‐key chamber produced food according to a second‐order variable‐interval schedule with fixed‐interval schedule components. A response on a second key (the changeover key) alternated colors on the main key and provided a second independent second‐order variable‐interval schedule with fixed‐interval components. The fixed‐interval component on one variable‐interval schedule was held constant at 8 sec, while the fixed interval on the other variable‐interval schedule was varied from 0 to 32 sec. Under some conditions, a brief stimulus terminated each fixed interval and generated fixed‐interval patterns; in other conditions, the brief stimulus was omitted. Relative response rate and relative time deviated substantially from scheduled relative reinforcement rate and, to a lesser extent, from obtained relative reinforcement rate under both brief‐stimulus and no‐stimulus conditions. Matching was observed with equal components on both schedules; with unequal components, increasingly greater proportions of time and responses than the matching relation would predict were spent on the variable‐interval schedule containing the shorter component. Preference for the shorter fixed interval was typically more extreme under brief‐stimulus than under no‐stimulus schedules. The results limit the extension of the matching relation typically observed under simple concurrent variable‐interval schedules to concurrent second‐order variable‐interval schedules.

Conditioned suppression was demonstrated in two experiments with rats lever pressing on a fixed‐ratio 1 schedule for lateral hypothalamic intracranial stimulation (ICS). In Experiment I, conditioned suppression of responding for low‐intensity ICS was obtained with a moderate intensity of foot shock. In Experiment II, low and high intensities of ICS were alternated within the same session and the same animal. The suppression that was exhibited with low‐intensity ICS was minimal or absent with high‐intensity stimulation, despite the pairing of foot shock with each warning stimulus. Conditioned suppression was a function of ICS intensity, and was independent of response rates. The inverse relationship between ICS intensity and degree of suppression is consistent with a motivational analysis of conditioned suppression. Previous reports of resistance to suppression of behaviors maintained by ICS may now be attributed to the use of high‐intensity stimulation.

Responding of three pigeons was maintained under conjunctive fixed‐ratio, fixed‐interval schedules where a key peck produced food after both schedule requirements were completed. The individual schedule requirements were then successively removed and reinstated with responding maintained under the following conditions: conjunctive fixed‐ratio, fixed‐time; fixed‐time; and fixed‐interval schedules. Patterns of responding changed in accord with the successive removal of the schedule requirements. Compared to the conjunctive fixed‐ratio, fixed‐interval schedule, pause duration increased and response rate decreased under conjunctive fixed‐ratio, fixed‐time schedules and under fixed‐time schedules alone. Overall mean rates of responding were highest and pause duration lowest under fixed‐interval schedules. When changes in the keylight colors were correlated with completion of the fixed‐ratio, the end of the fixed‐interval, or both of these conditions, the pattern of responding was modified and indicated a greater degree of control by the individual schedules. Although two birds showed large increases in interreinforcement time when they were initially exposed to the conjunctive schedule, when responding stabilized this measure was largely invariant for all birds across most schedule conditions.

The effect of informational feedback and graphing on reducing the number of arithmetic worksheet errors was investigated. The present study replicated and extended earlier findings with other populations (Journal of Applied Behavior Analysis, 1974, 7, 547–555; 1970, 3, 1–4; 1970, 3, 235–240) to a first‐grade classroom. Ten first‐grade pupils (four males and six females) served in an ABAB design. During the feedback‐only phase, subjects were provided informational feedback, in the form of a written number, on the number of errors made on individual arithmetic worksheets. The feedback‐only phase lasted seven days and was followed by the feedback‐plus‐graphing phase, during which subjects graphed the number (of errors written at the top of the individual worksheet) daily on individual graphs on their desks. The feedback‐plus‐graphing phase lasted 10 days and was followed by a reversal to feedback only for 10 days. The final phase was a replication of the feedback‐plus‐graphing phase. All subjects showed a change in number of worksheet errors, in the predicted direction, during the feedback‐plus‐graphing phases. An overall mean difference of −2.66 was found to be statistically significant (P < 0.01), using a Wilcoxson Matched‐Pairs Sign Test. The results were interpreted as being empirical support for earlier findings in other populations. In addition, the present findings represented a successful extension of feedback and graphing interventions to the management of academic behaviors in a first‐grade classroom.