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Three groups of pigeons were trained on a red‐green discrimination in which the stimuli were alternately presented in a multiple schedule of reinforcement. The discrimination was reversed 24 times. Groups were given 1, 2, or 4 hr of training on each discrimination. Increasing the length of training had two principal effects on reversal performance: it increased the rate of extinction of responding to one of the stimuli and increased the rate of reacquisition of responding to the other. The latter effect involved both an increase in reacquisition of responding to a positive stimulus within reversals and an increase in recovery of responding to the previous negative stimulus between reversals. Improvements in performance of each group over the series of reversals were qualitatively similar to the two effects of length of training on each discrimination, and were analogous to effects obtained in other studies involving overtraining and successive reversals of simultaneous discriminations.

Four rhesus monkeys were trained on a non‐discriminated shock‐avoidance schedule (baseline). Stimuli followed by response‐independent shock were then presented with the avoidance baseline no longer in effect. The main portion of the experiment consisted of superimposing (independently of responding) the stimuli followed by response‐independent shock on the avoidance baseline. Different temporal values of stimulus duration and delay of shock (produced by an avoidance response) were presented successively, using each subject as his own control. When the stimulus duration was short or the delay of shock was long, so that avoidance rate during the stimulus could assume any value without resulting in baseline (avoidable) shocks during the stimulus, a lowered or “suppressed” rate of responding developed during the stimulus. When the stimulus duration was long or the delay of shock was brief, so that avoidable shocks resulted from a response decrement during the stimulus, high or “facilitated” rates of responding developed for a large proportion of the time that the stimulus was present.

A kindergarten class, composed of five girls ages 4.8 to 6 yr, participated in the study. In each of 20 daily sessions a sequence of 10 simple instructions was given to the class, In baseline sessions, the teacher did not interact with the students, other than to give instructions. During these sessions, the children followed the teacher's instructions 60% of the time. When the teacher began attending to each child if she followed an instruction, the mean percentage of instructions followed increased to 78%. Subsequently, the teacher again employed the baseline procedures and the percentage of instructions followed decreased to 68.7%. When the teacher again provided attention dependent on the children's following the instructions, the percentage of instructions followed increased to 83.7%. The results are consistent with research that has treated instructions as discriminative stimuli. The general findings are that consequences of instructed behavior determine the extent to which the instructions are followed.

The effects of a token system on a teacher's rate of social contacts with her students were investigated in a public school kindergarten. A group of six children were observed daily during a 20‐min handwriting lesson. The children were divided into two groups (A and B) of three children each. Five conditions were imposed sequentially: (1) baseline without tokens, (2) contingent tokens for Group A, noncontingent tokens for Group B, (3) contingent tokens for Group B, noncontingent tokens for Group A, (4) reinstatement of condition 2, and (5) contingent tokens for both groups. It was consistently observed that the teacher's rate of social contact was higher with the children receiving the contingent tokens than with those who received noncontingent tokens.

Lever holding into shock and short‐latency responses to shock onset are two response patterns that interfere with avoidance acquisition in free‐operant and discriminated avoidance situations. In an attempt to eliminate these patterns, an additional timer disabled the lever for a period slightly longer than shock duration. A free‐operant avoidance schedule with a warning stimulus, but without the additional timer, constituted the control condition. The lever‐disabling timer was turned on by different events in two experimental conditions: (a) release of the lever at the onset of shock, (b) shock onset. Interfering responses diminished most rapidly, and efficient avoidance behavior appeared earliest, when the lever‐disabling timer was turned on by shock onset.

A method of observing and modifying teacher attention to appropriate child responses in preschool classrooms was developed. Two teachers with no formal training in reinforcement principles were observed for a baseline of eight days. Teacher A, who displayed a lower baseline rate of attending to appropriate child responses, was trained first. Teacher B was simply observed during the first part of the training condition for Teacher A. During training, A received feedback which included definitions of appropriate child responses, her frequency of attending to appropriate child responses, her total percentage of attending to appropriate child responses, and her frequency of failing to attend to appropriate child responses. Teacher B was then trained in a similar way. Both teachers showed an increase in attending to appropriate child responses subsequent to the onset of experimental feedback.

In an attempt to control severe vomiting in a mentally retarded patient, shock was delivered after each stomach tension, a pre‐vomiting response that consisted of an overt abdominal movement. Contingent shock resulted in an initial transitory increase followed by a decrease in rate of stomach tensions. There was a decrease in emitted vomitus, which resulted in a weight gain of the patient.

This series of four experiments sought to assess the comparative effects of multiple‐ versus single‐ratio schedules on a pupil's responding to mathematics materials. Experiment I, which alternated between single‐ and multiple‐ratio contingencies, revealed that during the latter phase the subject responded at a higher rate. Similar findings were revealed by Exp. II. The third experiment, which manipulated frequency of reinforcement rather than multiple ratios, revealed that the alteration had a minimal effect on the subject's response rate. A final experiment, conducted to assess further the effects of multiple ratios, provided data similar to those of Exp. I and II.

Pigeons were exposed to four different schedules of food reinforcement that arranged a fixed minimum time interval between reinforcements (60 sec or 300 sec). The first was a standard fixed‐interval schedule. The second was a schedule in which food was presented automatically at the end of the fixed time interval as long as a response had occurred earlier. The third and fourth schedules were identical to the first two except that the first response after reinforcement changed the color on the key. When the schedule required a peck after the interval elapsed, the response pattern consisted of a pause after reinforcement followed by responding at a high rate until reinforcement. When a response was not required after the termination of the interval, the pattern consisted of a pause after reinforcement, followed by responses and then by a subsequent pause until reinforcement. Having the first response after reinforcement change the color on the key had little effect on performance. Post‐reinforcement pause duration varied with the minimum interreinforcement interval but was unaffected by whether or not a response was required after the interval elapsed.

Goldfish were trained to swim back and forth in a shuttle tank to avoid unsignalled shocks. The response‐shock interval and the shock‐shock interval were always of equal duration; both were either 15, 30, 45, or 60 sec. Response rates varied inversely with response‐shock—shock‐shock interval duration, as has been found with rats. Percentage of shocks avoided was somewhat lower at the 15 sec response‐shock—shock‐shock interval, but otherwise did not vary systematically with changes in the interval. As the response‐shock—shock‐shock interval increased, the fish made increasingly more responses than necessary to avoid all shocks. Interresponse‐time distributions showed that response probability rose to a maximum at about 15 to 25 sec after a response, regardless of the response‐shock—shock‐shock interval. Thus, at the longer intervals the fish were responding too early in the response‐shock—shock‐shock interval to minimize response rates.