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Relative responding in initial links of concurrent‐chain schedules showed that pigeons preferred free to forced choices and informative to uninformative stimuli. Variable‐interval initial links on two lower keys (white) of a six‐key chamber produced terminal links on either two upper‐left keys (blue and/or amber) or two upper‐right keys (green and/or red). Terminal links in which pecks on either of two lit keys produced fixed‐interval reinforcement (free choice) were preferred to links with only one lit fixed‐interval key available (forced choice). Terminal links with different key colors correlated with concurrent fixed‐interval reinforcement and extinction (informative stimuli) were preferred to links with these schedules operating on same‐color keys (uninformative stimuli). Scheduling extinction for one of the two free‐choice keys assessed preference for two lit keys over one lit key, but confounded number with whether stimuli were informative. Fixed‐interval reinforcement for both keys in each terminal link, but with different‐color keys in one link and same‐color keys in the other, showed that preference for informative stimuli did not depend on stimulus variety. Preferences were independent of relative responses per reinforcement and other properties of terminal‐link performance.

Seven pigeons were trained to discriminate without errors between a green keylight and a dark key. The key‐pecking response was reinforced in the presence of green, and extinction was in effect in the presence of the dark key. The opportunity to attack a restrained target pigeon was present only during extinction. Both variable‐interval 30‐sec and fixed‐ratio 1 schedules of reinforcement during the positive stimulus induced a higher rate of attack during extinction than a variable‐interval 5‐min schedule. The highest rate of attack during extinction occurred during the first 20 sec after the positive stimulus terminated. Hence, the withdrawal of the positive condition, rather than the consequences of the pecking response during extinction, appears to be one of the primary factors responsible for attack between pigeons during extinction. Behavioral contrast, denned as a decrease in the rate of responding when the positive stimulus was presented alone, was obtained from the four birds that displayed the lowest overall rates of attack, while the three birds with the highest attack rates did not display behavioral contrast. For the birds without contrast, components of the attack response during the positive stimulus presumably competed with and reduced the rate of pecking the key, thereby precluding behavioral contrast.

After acquisition of a treadle‐pressing response maintained by an avoidance contingency, four groups of pigeons received interdimensional discrimination training. For two groups, the positive stimulus was a 1000‐Hertz tone correlated with the avoidance schedule and the negative stimulus was noise correlated with extinction. The discriminative stimuli were reversed for the other two groups. For two groups, the test stimuli were presented during extinction without any shocks during the test stimuli, for the other two groups, an unavoidable shock was presented during each test stimulus. Generalization was measured daily during discrimination training by randomly substituting each of six test frequencies for the 1000‐Hertz tone. When the 1000‐Hertz tone was correlated with the avoidance schedule, the number of responses to it increased and the excitatory gradient became steeper as a function of the amount of training. When the 1000‐Hertz tone was associated with extinction, the number of responses to it decreased as a function of days of training and the inhibitory gradient became slightly steeper, provided that responding to the test stimulus was elevated by unavoidable shock. The training effects parallel those obtained with positive reinforcement.

The effect of training on the rate of behavior‐specific praise for two fourth‐grade teachers was investigated within a multiple‐baseline design. Training teachers to identify instances of behavior‐specific praise on videotaped presentations (discrimination training) combined with instructions to use praise, and audiotape recordings of the teachers' classroom interactions as feedback, increased the rates of behavior‐specific praise. However, the effects were restricted to subject‐matter areas in which training was conducted.

Two retarded children were exposed to daily imitation training in which teacher or nurse modelled and instructed each child to imitate 12 sentences containing one of six animal names. The subjects were praised for correct verbal imitation. Across three phases of a multiple‐baseline design, sentences varied as to the presence or absence of size and/or color adjectives describing the animals. In probe sessions at another time of day and in a different setting, the experimenter twice asked each subject to describe 12 different animal pictures. The subjects' use of descriptive adjectives (color and/or size) greatly increased during probe sessions as a function of the sentence content (presence or absence of color and/or size adjectives) in modelling and imitation training sessions. Generalization to descriptions of animals also not used in imitation training sentences was also obtained.Generalization to descriptions of animals not used in imitation training sentences was also obtained.

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Using audiotaped descriptions of sexual experiences and a direct measure of penile erection, it is possible to specify more precisely erotic cues in sexual deviates. Results indicated that such cues are highly idiosyncratic. Some tentative conclusions and suggested application for the method are discussed.

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“Incidental teaching” denotes a process whereby language skills of labelling and describing are learned in naturally occurring adult‐child interactions. In the present study, 15‐min daily samples of the spontaneous speech of 11 children were recorded during free play over eight months of preschool. After incidental teaching of compound sentences, increases in unprompted use of compound sentences were seen for all the children, first directed to teachers, and then to children, in accordance with who attended to the children's requests for play materials. The incidental teaching procedure also stimulated spontaneous variety in speech, and appears to have general applicability to child learning settings.

Pigeons learned to discriminate between a positive stimulus (white key) and a negative stimulus (red or green key, depending on the subject) via Terrace's fading procedure. Generalization tests, conducted with intermittent reinforcement for key pecking at various wavelengths, yielded minima at the value of the negative stimulus in most “errorless” birds. Terrace's contrary finding of flat gradients in errorless subjects probably resulted from a floor‐effect (i.e., virtually zero responding) produced by his extinction‐test procedure. The present and other findings do not support Terrace's conclusions that the negative stimulus of an errorless discrimination is behaviorally neutral; inhibition apparently develops to the nonreinforced stimulus even during errorless discrimination learning. A negative correlation between stimulus and reinforcer seems the crucial factor in producing an inhibitory stimulus.