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Comparison was made of two methods for training monkeys to “observe” a two‐member serial position sequence by pressing two consecutively lighted keys and then to “report” the sequence by pressing the same two keys in the same order but without the lights. A fading technique involving gradual elimination of brightness cues from “reporting” keys was found more effective than a no‐fading procedure in which the cues remained bright during training and then were suddenly removed. Animals that failed to learn to report a new sequence with the no‐fading procedure sometimes developed behavior incompatible with that desired. They made repeated and specific errors that prematurely terminated trials of the sequence to‐be‐learned, even though the correct key was cued by a bright light. They behaved appropriately, however, on succeeding trials of other sequences. Thus, the errors were followed by trials on which reinforcement occurred. Manipulation of this contingency indicated its importance in maintaining the stereotyped error patterns.

Pigeons were exposed to four cycles per session of a schedule in which the duration of successive interreinforcement intervals differed by t‐sec. A cycle was composed of seven increasing and seven decreasing intervals, from 2t to 8t sec in length. In Exp. 1, postreinforcement pause tracked interval duration on five cyclic schedules, with values of t ranging from 2 to 40 sec. Tracking was better at shorter t values, and when discriminative stimuli signalled increasing and decreasing parts of the cycle. Pooled data for the whole experiment showed postreinforcement pause to bear a power function relationship to interval length, with a smaller exponent than the comparable function for fixed‐interval schedules. Tests in a second experiment showed that pigeons trained on an arithmetic progression could also track schedules in which successive intervals followed either a logarithmic or a geometric progression, although tracking was more stable in the logarithmic case.

Pigeons learned a successive discrimination between a positive stimulus (red) correlated with a variable‐interval 1‐min reinforcement schedule and a negative stimulus (vertical line) correlated with either a variable‐interval 5‐min schedule or extinction. Transfer tests measured the rate of responding to the positive stimulus alone, to various orientations of the negative stimulus, and to the same line orientations superimposed on the positive stimulus. Although there were no gradients with minima at the training value for the negative stimulus dimension, the addition of the negative stimulus dimension to the positive stimulus always resulted in a lower response rate than that for the positive stimulus alone. The results demonstrate that an operational definition of inhibitory stimulus control that requires increased responding to stimuli more distant from a negative stimulus (along some dimension) is not always consistent with a definition that requires the suppression of responding in the presence of one stimulus, the positive stimulus, by the simultaneous presentation of another, the negative stimulus.

After a period of equal reinforcement for choices of any job revealed which of 10 jobs each of 24 preschool children preferred and did not prefer, token payment became dependent on particular choices. Some children received tokens only for choosing previously non‐preferred jobs, others for choosing previously preferred jobs. When tokens depended on choosing the nonpreferred jobs, those came to be preferred. When tokens depended on choosing the preferred jobs, the preferences were strengthened. The effects were replicated both within and between subjects, except in the case of one boy who consistently avoided token pay.

A multiple baseline technique was employed to examine the experimental development of an imitative repertoire within preselected topographical boundaries. Four severely retarded children, initially nonimitative, were individually trained to imitate a number of motor and vocal responses by shaping and fading procedures. Other untrained responses (probes) were demonstrated to the subjects systematically throughout the ongoing training. Training responses were divided into three topographical types: small motor, large motor, and short vocal responses. Probe responses were divided into four topographical types: small motor, large motor, short vocal, and long vocal responses. Following a multiple baseline format, sequential training of the first three types was begun at different temporal periods of the study; unreinforced imitative generalization was continually measured by the probes. Generalized imitation was observed in each subject (untrained responses were imitated even though unreinforced); but this generalization was restricted to the topographical type of imitation currently receiving training or having previously received training.

Intermittent grading of papers and the combination of intermittent grading with contingent access to play were evaluated as methods for increasing the accuracy of kindergarten children's printing responses. For a group of target letters, intermittent grading alone failed to produce an increase in accuracy, but when grading was paired with access to play, accuracy increased for every child. These results were then replicated with another letter.

The effects of self‐recording on classroom behavior of two junior high school students was investigated. In the first experiment, study behavior of an eighth‐grade girl in history class was recorded. Following baseline observations her counselor provided slips for the girl to record whether or not she studied in class. This resulted in an increase in study. When slips were withdrawn, study decreased and then increased once self‐recording was reinstated. After teacher praise for study was increased, self‐recording was discontinued without significant losses in study behavior. In the final phase, increased praise was also withdrawn and study remained at a high level. In the second experiment, the number of talk outs emitted by an eighth‐grade boy were recorded during math period. Following baseline, slips for recording talk outs were issued for the first half of the period, for the second half, and then for the entire period. Talk outs decreased when self‐recording was in effect and increased again when self‐recording was discontinued. When self‐recording was reinstituted in the final phase there was a slight, though not significant decrease in talking out when compared to the baseline condition.

The major dependent variable was the rate at which first and second‐grade students printed or wrote daily copying assignments. Data were also taken on the percentage of letters scored as errors according to a set of scoring criteria. Initially, these data were collected during a baseline condition in which each child returned to his seat as soon as his completed work had been scored, to wait for the rest of the class to finish their assignments. When the children were allowed to go to a playroom after their papers had been scored, there was a reliable increase in the mean printing or writing rates. Subsequent introductions of the baseline and playroom conditions replicated the relative effectiveness of access to the playroom to produce higher work rates. Finally, the total amount of time allowed for children to complete their assignments and then play was progressively reduced from 50 to 35 minutes. A progressive increase in work rates was correlated with these changes. Throughout the experiment, there was considerable variability in the mean number of letters scored as errors but there was a clear trend towards fewer errors.

The effects of briefly presented stimuli paired or not paired with food reinforcement were investigated in the pigeon on a multiple schedule containing second‐order schedules. A stimulus paired with food reinforcement was presented on a variable‐interval schedule in one unit of the multiple schedule and either a stimulus not paired with food reinforcement or no stimuli were scheduled in the other unit. Response rates were highest when behavior was followed by the food‐paired stimulus. Presentation of the food‐paired stimulus at completion of each 1‐min variable‐interval component maintained a steady rate of responding between consecutive food presentations. Pausing following food reinforcement was greatest in the second‐order schedule not containing the paired stimulus. Reversing the stimulus pairings led to a reversal of the relative response rates and patterns of responding for each stimulus.

The present study attempted to assess one condition of language exposure that might be operative in a normal environment, and experimentally determine its relevance to the acquisition of productive speech. The results demonstrated that the development of receptive language skills can be functionally related to productive speech. Specifically, the data indicated that exposure to words that have stimulus control over a subject's nonverbal pointing behavior can facilitate later articulation of those same words. Thus, this study draws attention to the fact that at least some classes of operants, in this case verbal, can be affected not only by their consequences, but by not obviously related antecedent events as well.