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Four pigeons were trained to peck at either of two response‐keys. Pecking at either key occasionally produced a secondary reinforcer. Then, in the presence of the secondary reinforcer, further pecking occasionally produced the primary reinforcer, food. The relative rate at which each pigeon pecked to obtain a secondary reinforcer equalled the relative rate of primary reinforcement in its presence.

Key pecking of pigeons was reinforced with grain on a progressive ratio schedule during the presence of either of two key colors. Under one color, all responses were shocked; under the other color, responses were not shocked. A single response on a second key switched the key color and reset the progressive ratio, provided that the first step of the progressive ratio had been completed. A preference developed for the longer ratios of the progressive ratio under the non‐shock key color. When the severity of punishment suppressed responding under the key color correlated with shock, the subjects continued to switch to the shock condition after a moderate degree of responding under the non‐shock condition. Severe punishment also resulted in frequent, ineffective responses on the switching key and extended pausing under the key color associated with shock.

Key‐pecking of pigeons, maintained by an FR 50 grain reinforcement schedule, was punished by shocking the first, middle, or last response of the ratio. Under high shock levels, the three punishment conditions produced differential effects on the behavior. Punishment of the first response of the ratio resulted in consistent and extended post‐reinforcement pausing and frequent extended breaks after the initial response(s) of the ratio. Punishment of the 25th response disrupted responding in the first half of the ratio with little effect on the last half of the ratio. Punishment of the final response resulted in breaks and local rate changes in various parts of the ratio. Durations of pauses after reinforcement were more variable when the 25th and 50th responses were punished relative to those when the first response was punished.

Five three‐man teams were conditioned to a multiple DRL‐DRH schedule during five daily sessions of 3 hr each. The teams were conditioned on the basis of their cumulative response rate regardless of the contributions of individual members. Two individually conditioned Ss were run under a similar schedule for comparison. Although all teams demonstrated some differentiation of response rate under the two legs of the schedule, this difference was not achieved as rapidly, nor was it as stable, as the differentiation in rates achieved in individually conditioned Ss. Team members displayed a variety of response rates as a result of collective team conditioning. Often, individual response rates interfered with obtainment of team reinforcement. The individual team members displayed little SD control in comparison with the individually conditioned Ss. In general the results suggest that collective reinforcement is highly inefficient in comparison with procedures employing individual feedback.

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Three hooded rats were trained to bar press for variable‐ratio liquid reinforcement after which an electric shock was delivered following the response. Initially, the shock was presented on a FR 100 basis but the frequency was gradually increased until all responses were punished. Finally, a partial extinction procedure was conducted to determine if the shock resulted in increased bar pressing. No durable suppression of responding occurred, although one subject's rate was reduced during continuous shock. The overall trend for the three animals was one of increased responding. Changes in the pattern of responding were also observed suggesting that the suppressive effects of the punishment were largely restricted to the first response following reinforcement. Increased responding as a function of shock reintroduction during extinction was also observed.

Two pigeons were trained on an FR 150 schedule of reinforcement. An Estes‐Skinner conditioned suppression procedure was then superimposed on this performance at varied intervals. If the CS occurred during the early stages of the ratio run, complete suppression resulted. If the CS occurred during the later stages of the run, the birds continued to respond until the reinforcement was obtained, which was then followed by complete suppression.

Pigeons produced food on a fixed‐ratio schedule by pecking at one key, and an SΔ period by pecking at a second (switching) key. Switching behavior was examined as a function of (a) size of the fixed ratio, (b) whether the SΔ was of fixed duration or could be determined by the bird, (c) the introduction of a novel food SD, (d) extinction of food responding, and (e) the stimuli associated with the SD and SΔ conditions. No monotonic relationship was obtained between ratio size and switching behavior. Switching behavior was, however, influenced by many variables. The results suggest that an interpretation of switching behavior in terms of its being reinforced by the removal of aversive conditions, is open to considerable question.

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