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Key pecking in pigeons can be engendered by associating response‐independent food presentations with illumination of a key. Specific pairings of key and food are not necessary for this phenomenon. Differential positive association between key and food (defined in terms of relative densities of reinforcement), however, is necessary and sufficient to produce and maintain key pecking. Thus, the occurrence of key pecking in auto‐shaping can be considered to depend on associative processes similar to classical conditioning. Consequently, auto‐shaped pecking can be virtually eliminated by the addition of food presentations in the intertrial interval, thus removing the association between key and food. Initial exposure to random reinforcement, or reinforcement only in the absence of the key, results in lower rates of pecking in subsequent auto‐shaping procedures.

Three pigeons were trained in an upright conditioning chamber to peck a key transilluminated by a vertical line. This training was followed by a line orientation generalization test. During the test, the chamber was tilted laterally 22.5 degrees from upright. The chamber floor remained horizontal with respect to gravity. Under these conditions, the subjects responded more often in the presence of a visually vertical (parallel to chamber walls) line orientation than in the presence of a gravitationally vertical line orientation. Subsequent reinforcement of pecking in the presence of a line that was always gravitationally vertical but not always visually vertical temporarily abolished this “visual field dependency” and resulted in generalization gradients with peak responding in the presence of the gravitationally vertical line orientation. The results are discussed in terms of selective attention to the gravitational and visual components of line orientation.

Human subjects, mostly between 11 and 16 yr old, matched to sample for points that were exchangeable for money. An audit response was defined as a response maintained by allowing a subject access to an existing score on his own (self audit) or a coactor's (coactor audit) performance. In Experiment I, changes from non‐social procedures (no coactor) to social procedures (coactor present) increased self and coactor audits. Since both types of audits occurred at about the same rates during cooperation and parallel work procedures, the increases did not depend on the subjects' response interactions. Although Experiment I did not demonstrate that subjects were comparing scores, the frequent occurrence of each kind of audit within a brief time period (interpersonal audit) did indicate that it was reinforcing to have both scores at the same time. These interpersonal audits suggested that the coactor's score increased self audits during social procedures. Experiment II supported this notion: relative to a non‐social procedure, self audits increased more during a parallel work procedure when the coactor's score was accessible than when it was not accessible. Thus, increases in other behaviors that occur in the presence of a coactor, i.e., social facilitation, may also result from or be increased by providing a coactor's score.

Rats learned either a lever‐press response, a shuttle response or a one‐way crossing response, which produced one immediate shock but was instrumental in avoiding five identical shocks scheduled to occur later. These responses were acquired both with and without support of an escape contingency. These results support shock‐frequency reduction as a sufficient condition for the acquisition and maintenance of avoidance.

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Rats responded on a multiple fixed‐interval fixed‐interval schedule of reinforcement. Each complete cycle of the multiple schedule was separated from the next by a relatively long period of timeout from all schedule contingencies. A response at the end of the second component of each cycle was always reinforced with an invariant reinforcement magnitude, while reinforcement magnitude and reinforcement omission were systematically varied in the first component. Response rate in the first component was a monotonic function of reinforcement magnitude in that component. These changes in response rate in the first component did not affect response rate in the second component. When reinforcement was omitted on 50% of occasions in the first component, following reinforcement there was a reduction in response rate in the second component that was monotonically related to reinforcement magnitude. Following reinforcement omission there was an increase in response rate in the second component that was unrelated to reinforcement magnitude. When reinforcement was omitted on 100% of occasions in the first component, behavioral contrast was observed.

Cebus albifrons monkeys received electrical stimulation of the hindlimbs over a wide range of intensities. On trials signalled by a blue light, the animals were permitted to escape shock by pressing a disc, or shock was terminated after 8 sec (free escape). Escape force (disc pressure) was found to increase as stimulation intensity increased well beyond escape threshold, while shock duration curves reached plateau at the mid‐range of intensities. The shock duration curves generated by free escape responses should be comparable to pain detection functions obtained by similar operations in humans, and the curves were stable over months of testing, as is generally found in pain‐detection studies. On trials signalled by a red light, the animals received intense tail shock immediately after escape responses (punished escape), or, if they endured leg shock for 8 sec without escaping, then they could avoid tail shock with a panel press. The shock duration curves generated by punished escape responses should be comparable to pain tolerance functions as defined for human subjects, and the escape thresholds were considerably higher on red‐light trials. As in human studies, the tolerance curves were not stable over repeated testing sessions, and some feature of the paradigm forced a progression toward extremely high levels of tolerance.

Pigeons received discrimination training in which the presence of a white field was correlated with variable‐interval reinforcement and the presence of a monochromatic field was correlated with extinction. Responses during the negative stimulus prolonged its duration. Five experimental groups each received a different number of discrimination sessions up to 70 sessions. The last session was followed by a wavelength generalization test. The control group was tested both before and after four discrimination sessions. Responding to the positive training stimulus was enhanced in all groups by the discrimination procedures. This enhancement tended to decrease over sessions in some animals but it never disappeared in others. Responding to the test stimuli preceding discrimination training was minimal around the negative stimulus and increased in either direction away from that wavelength. Responding to the test stimuli was not systematically related to the amount of discrimination training.