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Pigeons pecked two response keys to move a white dot until it was equidistant from two other dots on a screen. Continuous records of dot position showed the effects of reinforcement and stimulus parameters upon the accuracy with which the dot was positioned. The method may prove useful for studying the perception of distance in non‐human organisms.

Pigeons were trained to discriminate the duration of a stimulus. One response in a psychophysical choice situation was reinforced, given the immediately prior presentation of a stimulus duration in one class of durations called short durations, and the other response was reinforced given the immediately prior presentation of a stimulus duration in a second class called long durations. Durations of equal logarithmic difference from the cutoff, whether in the short or long class, yielded equal accuracy. Accuracy was a function not only of the properties of the stimuli to be discriminated, but also of the experimental contingencies used. Accuracy was greater in variable‐ratio than in fixed‐ratio schedules of reinforcement of the discriminative responses, and was lower at the beginning than later in individual fixed ratios. Proportion of short or long responses (response bias) was affected by sequential dependencies among long and short durations and was effectively controlled through the use of asymmetric reinforcement and fixed‐ratio contingencies.

Pigeons were studied in two experiments designed to explore the effects of deprivation level upon responding in each link of a two‐link chained schedule. The stimulus associated with the terminal link of the chain can be both a discriminative stimulus (SD) for responding in the presence of the stimulus and a conditioned reinforcer (Sr) for responding in the preceding link. Previous findings have indicated that the Sr function was more readily weakened by satiation than was the SD function, i.e., the rate of responding decreased more rapidly in the initial link of the chain than in the terminal link. The first of the present experiments, in which tests were conducted after a series of sessions, produced different results: rates of responding in the two links declined simultaneously. The second experiment supported the hypothesis that the effects of satiation interact with the duration of maintenance on the satiation procedure: in early sessions the Sr function was more readily disrupted, but in later sessions the rates of responding in the two links declined simultaneously. Subsequent to this extensive series of identical sessions, the pigeons' deprivation level was altered before a session by pre‐feeding the pigeons up to their normal post‐session weights. The rates of responding failed to reflect fully this change in deprivation in the first such session, suggesting that the pigeons' behavior had become partially independent of deprivation level.

Three pigeons' pecks were reinforced on 1‐ and 2‐min variable‐interval schedules, and frequency distributions of their interresponse times (IRTs) were recorded. The conditional probability that a response would fall into any IRT category was estimated by the interresponse‐times‐per‐opportunity transformation (IRTs/op). The resulting functions were notable chiefly for the relatively low probability of IRTs in the 0.2‐ to 0.3‐sec range; in other respects they varied within and between subjects. The overall level of the curves generally rose over the course of 32 experimental hours, but their shapes changed unsystematically. The shape of the IRT distribution was much the same for VI 1‐min and VI 2‐min. The variability of these distributions supports the notion that the VI schedule only loosely controls response rate, permitting wide latitude to adventitious effects. There was no systematic evidence that curves changed over sessions to conform to the distribution of reinforcements by IRT.

In a Sidman‐avoidance schedule of counter losses for two human subjects, the loss‐to‐loss and response‐to‐loss intervals were 20 sec. The avoidance response was a vocal response that was louder than a minimum vocal requirement. This requirement was set at 80 db, 95 db, or 110 db. In addition to vocal responses meeting the minimum requirement, all responses exceeding a threshold of 75 db or louder were recorded. The rate of both above‐threshold and avoidance responses decreased as the response‐force requirement increased. Thus, high response‐force requirements produced an effect on avoidance responding similar to its effect on positively reinforced responding.

Duration of the post‐reinforcement pause was measured for three pigeons on fixed‐ratio schedules of reinforcement ranging from 10 to 160. Small sequential changes were made in the ratio values without disrupting stable performance. The post‐reinforcement pause increased consistently for all birds within three sessions as the ratio requirement increased. A frequency analysis of the individual pauses at selected fixed ratios revealed an increase in dispersion for all animals as the ratio size increased. Response rate tended to decrease for two of the birds and remained relatively stable for the third; but there were many reversals in these data.

Timeout procedures in the home and extinction and reinforcement of incompatible behaviors in the laboratory failed to eliminate the disruptive and dangerous climbing behavior of a deviant child. Punishment with electric shock was used to eliminate this behavior in the laboratory and then in the home. The effects were reversible and were restricted to specific stimulus conditions. A less severe form of punishment was used to eliminate the child's autistic rocking. Other behaviors of the subject were continuously measured in the laboratory to determine the side effects of punishment. No suppression of other behaviors correlated with punishment was noted. However, the rate of some behaviors increased when punishment was used to eliminate deviant behaviors, but these increases were, primarily, desirable.

Methods were compared for teaching severely retarded boys to discriminate the position of a 0.75‐in. black square and to press the response key closest to it. Seven boys were given trial‐and‐error training; one learned the task. The six boys who did not learn were presented with a program of graduated stimulus changes. All but one acquired the performance, and he was under appropriate control during the program. When he reached the criterion stimuli, he reverted to a position‐based response learned during trial‐and‐error training. Six similar subjects were presented with graduated stimulus training alone. All six learned the criterion discrimination with few or no errors. Both groups were tested for retention of the criterion performance 35 days after training was completed. Two boys who had near‐perfect criterion discrimination performances showed no signs of retention after 35 days. These boys had a history of trial‐and‐error training.

Social greeting responses of three withdrawn, chronic schizophrenics were experimentally modified. Initially, none of the subjects spoke to an experimenter. Prompts and cigarette reinforcement were employed to produce increases in the rates of greetings. Then, the prompts were faded so that the greetings came under the control of the presence of the experimenter. Reversal and subsequent reinforcement procedures were employed to demonstrate that the responses were controlled by their consequences. Next, the schedule of cigarette reinforcement was leaned out so that greetings continued to occur in the absence of cigarette reinforcement. However, low or zero rates of greetings occurred in the presence of a second experimenter. Five new experimenters employed the prompting, fading, reinforcement, and schedule‐leaning procedures. Subsequently, all subjects emitted appropriately high rates of greetings in the presence of the second experimenter. Without further application of the experimental procedures, greetings were still occurring in the presence of both the first and second experimenters almost three months later.