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The transition from fixed‐ratio 1 performance (every response reinforced) to fixed‐ratio 30 performance (every thirtieth response reinforced) was studied in nine pigeons. These were divided into three treatment groups given daily oral doses of saline, or 250 mg/kg/day or 500 mg/kg/day of yeast ribonucleic acid. Detailed computer‐assisted analyses of how fixed‐ratio behavior develops revealed the following typical sequence. After the transition, the first few ratios typically were emitted without long interresponse times within the ratio. Steady responding then ceased, and numerous long interresponse times occurred, with no systematic relationship to ordinal position within the ratio. Gradually, a new pattern evolved, characterized by a consistently long post‐reinforcement time, a border region of the next few interresponse times within which the mean interresponse time monotonically decreased, and short interresponse times within the last 80% of the ratio. Long interresponse times were eliminated from this last section of the ratio without regard to proximity to reinforcement. Various analytical procedures suggested that the final pattern can be conceived, in part, as the shaping of a reliable response topography. The group of three pigeons given 250 mg/kg/day of yeast ribonucleic acid responded at higher rates than the saline and 500 mg/kg/day groups. The latter group, in contrast to the saline and lower dose groups, which continued to increase their rates, reached a rate asymptote very early.

In two experiments, the effect of an illuminated response key on the acquisition of stimulus control by an airflow stimulus was assessed. In the first experiment, pigeons were given nondifferential training with airflow emerging from behind the response key in one of three conditions of illumination: trained to peck a lighted key, trained to peck an unlighted key with a houselight present, trained to peck a key in total darkness. After 10 days of training on a variable‐interval schedule of reinforcement, all subjects were given a generalization test on airflow velocity. The gradients for subjects trained in the dark were sharp, while those for subjects trained in lighted conditions were shallow. In the second experiment, the effect of an irrelevant keylight on the acquisition of an airflow velocity discrimination was assessed. Two groups of pigeons were trained to discriminate two airflow velocities. One group was trained with a lighted response key and the other was trained to peck the response key in total darkness. The dark‐trained subjects acquired the discrimination more rapidly. The results demonstrate that the acquisition of stimulus control by airflow with either a differential or nondifferential training procedure can be overshadowed by keylight.

Most previous research on the effect of the duration of preceding discrimination training on responding to a new stimulus has measured the responding during extinction. To reduce effects originating in the extinction procedure itself, the present study assessed the effect of discrimination training on responses to a new negative stimulus added during continued discrimination training. Pigeons were given a new negative stimulus (blue key) after 0, 1, 3, or 9 days of discrimination training with a yellow key as the positive stimulus, and both a green key and a red key as negative. Fewer responses were made to the blue key when it was introduced after nine days of discrimination training than after less discrimination training. That effect of long discrimination training agrees with reported results from extinction tests. However, the effect of briefer discrimination training in the present study differed from reported results with extinction testing. It appears that testing during continued discrimination training eliminates a distortion present in extinction tests of the effect of discrimination training on responding to a new stimulus.

Three retarded boys served as subjects in a 13‐phase experiment. In eight of these phases, the instructions administered by the experimenter before demonstrating a behavior and the consequences for imitative behavior were incongruent (the consequences were not those indicated by the instructions). Consequences rather than instructions controlled imitative behavior when (a) subjects were instructed not to imitate but received reinforcers if they imitated; (b) subjects were instructed to imitate but were differentially reinforced for other behavior; (c) subjects were instructed to imitate but were verbally reprimanded for imitation. Although subjects were highly imitative at the beginning of the study, when there was no reinforcement for imitation subjects gradually stopped imitating when instructed not to imitate. Instructions seemed to control imitative behavior when there was no reinforcement for imitation and subjects were instructed to imitate. These results indicated a need for further investigation of antecedent and consequent variables in imitation experiments and pointed out that certain techniques may be more efficient than others in eliminating well‐established responses.

This experiment studied the effect on intelligence test scores of a probable reinforcer given for correct responses. Eleven pairs of 5‐ to 7‐yr‐old children were matched on the basis of a strong liking of candy, no physical problems associated with eating it, parent permission to receive and eat the candy, age, sex, and a revised Stanford‐Binet Scale Form L IQ score. The control group was given the revised Stanford‐Binet Scale Form M, as prescribed in the test manual. The experimental group was also given Form M according to the manual, except M&M candy was given for each plus or correct response. There was an appreciable, statistically significant difference between the resulting IQ test scores of the two groups.

Comparisons were made between reading programs that involved superimposition of correlated pictoral and printed stimuli, fading of the pictoral stimuli, and overt observing (touching) responses. Nursery school children aged 4 to 5.8 yr learned and retained oral reading behavior better when fading was used; observing responses had no effect.

Previous work using variable‐interval schedules in the terminal links of concurrent chained schedules suggested that relative choice proportion in the initial links equalled relative rate of reinforcement in the terminal links. With fixed‐interval terminal‐link schedules, however, matching was not obtained. The present study held pairs of fixed‐interval terminal‐link schedules in a constant ratio but varied absolute sizes. Relative choice for the smaller terminal‐link fixed‐interval schedule was a negatively accelerated, increasing function of absolute size of the fixed‐interval pairs. Matching was found only with the fixed‐interval pair of 5 and 10 sec. When pairs of variable‐interval schedules were arranged so that the harmonic mean of the intervals equalled the fixed‐interval parameter values, relative choice functions were like those for fixed‐interval schedules.

Prior research with token reinforcement in the psychiatric population has been directed at work adjustment, more than at major symptomatic behaviors. The purpose of the present research, on the other hand, was to investigate the effects of feedback and token reinforcement on the modification of delusional verbal behavior in chronic psychotics. Six male and four female paranoid schizophrenic patients participated in the study. The results indicated that the effects of feedback were effective about half the time in reducing percentage delusional talk, but in at least three cases produced adverse reactions. Token reinforcement, however, showed more consistency and reduced the percentage of delusional verbal behavior in seven of the nine subjects exposed to this procedure. The effects of both feedback and token reinforcement were quite specific to the environment in which they were applied and showed little generalization to other situations. It would appear that using token reinforcement can reduce the percentage delusional speech of chronic paranoid schizophrenics.

Parent‐child problems within the home are frequently reported to be instances in which children refuse to help with household chores, bicker among themselves, or engage in verbally inappropriate behavior toward their parents. The present study investigated the effects of a token reinforcement program administered by the parents in ameliorating these problems. Two sets of parents, with a total of five children between the ages of 5 and 10 yr, were taught to administer a token economy within their homes. The parents received instruction in specifying desired social and chore behaviors, communicated these behavioral goals to their children, recorded data on their occurrence, and managed a point system backed with reinforcers normally found in the home. The token reinforcement program was shown to have successfully modified 15 problem behaviors in Family 1 and six in Family 2. In addition, the parents rated all 21 behavior changes as significant improvements. These studies indicated that some cooperative parents need only a small amount of professional help to learn to manage their children's behavior problems with token reinforcement procedures.

Two experiments demonstrated the pigeon's sensitivity to ultraviolet light. In Experiment I, pigeons' responses were reinforced on a multiple schedule with a variable‐interval reinforcement schedule in one component and extinction in the other component. Response rates were quite different in the two components where the 520‐nm stimuli signalling each component differed only in that one of them contained a 366‐nm ultraviolet component. In Experiment II, pigeons were trained to peck one side key when two halves of a split field were of different wavelength and to peck another side key when they were of the same wavelength. Initially, field halves contained both “visible” and ultraviolet components of energy. Discrimination performance improved when the ultraviolet component was removed from one field half. It was argued that the critical change in the stimulus was a color change, rather than a brightness one, or a fluorescence of structures in the pigeon's eye.