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Four pigeons were trained under concurrent variable‐interval variable‐interval and fixed‐interval variable‐interval schedules in a two‐key situation. Both response allocation and time allocation to the two schedules were measured when various reinforcement rates were arranged on each key. All animals showed an approximately constant proportional preference for the variable‐interval schedule over the fixed‐interval schedule. These results support Schneider's (1969) analysis of fixed‐interval schedule performance.

The performances of five pigeons were studied under a variety of multiple fixed‐interval schedules in which both component duration and reinforcement rate were varied. The three series of experimental conditions were: (a) when the ratio of component durations equalled the reciprocal of the ratio of component reinforcement rates; (b) when the component durations were equal; and (c) when the ratio of component durations equalled the ratio of component reinforcement rates. Relative response rates were related to relative reinforcement rates in the same manner as in multiple variable‐interval schedules, but no effect of component duration was found.

The effect of increases in the rate of responding in one component of a multiple schedule upon the rate of responding in a second component was investigated. Pigeons were exposed to a multiple schedule where both components were initially variable‐interval schedules having the same parameter value. After rate of key pecking stabilized, one component was changed to a schedule that differentially reinforced high rates of responding. Rate of reinforcement in this varied component was adjusted to remain equal to rate of reinforcement in the constant (variable‐interval) component. Four of five pigeons showed a maintained increase in rate of responding during both the constant and varied components, even though rates of reinforcement did not change.

Fixed‐ratio behavior of monkeys was analyzed separately for two hands. While one hand responded on the fixed‐ratio schedule the other performed a holding response and the function of the hands changed in alternate ratio runs. After performance was stable on the fixed ratio (70 responses, two monkeys; 100 responses, two monkeys, 120 responses, two monkeys) 90 sessions of further training equalized post‐reinforcement pauses and the mean interresponse time of the two hands. Hand preference in reaching for food remained unchanged. Then, the fixed‐ratio requirement was changed (a) in small sequential steps, (b) in two large steps, and, (c) within sessions alternating two runs at a high ratio with two runs at a low ratio. The mean duration of post‐reinforcement pauses was correlated with a fixed ratio maintained throughout a session but single pauses were neither controlled by the immediately preceding nor by the following ratio run when a cue to its length was available. The mean interresponse time was insensitive to changes in fixed ratio. The fixed‐ratio performance was generally similar to that of pigeons and rats.

Food‐deprived pigeons pecked a key under a schedule in which grain was made available after the seventieth peck. In each sequence of 70 responses, either the first, middle, or final response was followed by electric shock. Before the first response of each sequence, each response on a second key changed the color of the food key and the schedule of shock that was correlated with the food key color. Each pigeon preferred a schedule of shock, in that each of the three shock schedules did not occur equally often. The preferred shock schedule and the strength of the preference varied among the pigeons. The overall rate of responding by a pigeon under a given shock schedule was directly related to the pigeon's relative preference for that schedule, except when shock after the first response in the sequence was the most preferred schedule.

Six pigeons were trained under a concurrent chains procedure so that preference for fixed‐interval versus mixed‐interval schedules with varying numbers of component intervals could be examined. The smallest and largest intervals in the terminal links were the same value as those used by Davison (1969). Relative choice in all cases approximated the relative means of the squares of the harmonic intervals to reinforcement in the terminal links, and no effect of number of component intervals was demonstrated. Mixed‐interval versus fixed‐interval choice could not be predicted from extant data on fixed‐interval versus fixed‐interval choice.

Pigeons were trained on a probability learning task where the overall reinforcement probability was 0.50 for each response alternative but where the momentary reinforcement probability differed and depended upon the outcome of the preceding trial. In all cases, the maximum reinforcement occurred with a “win‐stay, lose‐shift” response pattern. When both position and color were relevant cues, the optimal response pattern was learned when the reinforcement probability for repeating the just‐reinforced response was 0.80 but not when the probability was 0.65. When only color was relevant, learning occurred much more slowly, and only for subjects trained on large fixed ratio requirements.

Effects of three experimental and one control strategy were investigated in facilitating generalization and maintenance of treatment effects after two months in a token‐economy classroom. At the conclusion of treatment, subjects were randomly assigned to one of three maintenance strategies or a control group and returned to their regular classrooms. The maintenance strategies were peer reprogramming, equating stimulus conditions between the experimental and regular classrooms, and teacher training in behavior management techniques. The maintenance strategies were implemented in the regular classroom for a two‐month period and then terminated. Results indicated a powerful treatment effect produced by the token economy. Behavior maintenance effects following treatment were also obtained. The mean per cent appropriate behavior for the peer reprogramming and equating stimulus conditions strategies was significantly greater than the mean for the control subjects. The teacher training and control group means were not significantly different.

Punishment of bar‐pressing responses of rhesus monkeys with electric shock in one component of a multiple free‐operant avoidance schedule suppressed responding in that component. These decreases were concomitant with response rate increases in the unpunished component (punishment contrast). Response rates in both components increased when punishment was removed and decreased in successive sessions. These effects of punishment on unpunished responding were similar to those obtained during single and multiple schedules of positive reinforcement and they suggest a further similarity in the development of discriminations during positive and negative reinforcement schedules.

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