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Pigeons working for food on a multiple variable‐interval 1‐min—variable‐interval 4‐min schedule were subjected to variations in body weight, presumably causing changes in hunger. The proportion of responses in each component approached and eventually reached the proportion of reinforcements as body weight increased. This effect follows from the matching‐law interpretation of contrast in multiple schedules.

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In most federal job training and employment programs, trainees' pay is not contingent on job performance, but upon physical presence. This study sought to increase the job performance of seven Neighborhood Youth Corps workers being paid an hourly wage for serving as aides in an urban recreation program. When thorough job descriptions and threatened termination of employment were insufficient to maintain adequate job performance, an attempt was made to make the hourly wage (required by the Neighborhood Youth Corps program) more contingent on job performance. When the number of hours credited the workers on their payroll sheets was proportional to their rating on a simple checklist of job performance, rather than to the number of hours they were present, their job performance was maintained at near‐perfect levels. Although this simple semantic shift in emphasis—from “hours worked” to “hours worked”—was still interpreted as meeting the Neighborhood Youth Corps requirements for hourly pay, its behavioral effects were substantial. This simple procedure might be used in other training programs handicapped by hourly wage requirements.

Pigeons were given a small, immediate food reinforcement for pecking a key, and a larger, delayed reinforcement for not pecking this key. Most subjects pecked the key on more than 95% of trials. However, when pecking a differently colored key at an earlier time prevented this option from becoming available, three of 10 subjects consistently pecked it, thereby forcing themselves to wait for the larger reward. They did not peck the earlier key when it did not prevent this option. This is an experimental example of psychological impulse and a learnable device to control it. Although only a minority of the subjects learned it, the fact that such learning is possible at all argues for a theory of delayed reward that can predict change of preference as a function of elapsing time.

Rural black, economically impoverished Head Start children, whose normal diets were deficient in nutritional requirements, were not consuming the nutritional breakfasts of, to them, unfamiliar foods provided by the county school system. This study investigated a positive simple method to increase the amount of food consumed and thereby ensure proper nutrition. Teachers dispensed sugar‐coated cereal and small candies paired with praise contingent on eating behaviors and rewarded children who finished the entire meal with additional treats and praise. Substantial increases were produced in the proportion of meals consumed and in the number of children observed engaged in eating behaviors. These simple traditional behavioral procedures are readily available for any staff working with economically impoverished children as one method of increasing their sampling and consumption of unfamiliar nutritious foods.

Appropriate play with toys was studied in two autistic children with high occurrences of self‐stimulatory behavior. Each child participated in the experimental sessions in an A‐B‐A design, where “A” refers to baseline sessions and “B” refers to self‐stimulation suppression sessions. It was found that: (a) during the baseline sessions, the children exhibited low levels of play and high levels of self‐stimulatory behavior; (b) the per cent of unreinforced, spontaneous, appropriate play increased when self‐stimulatory behavior was suppressed; and (c) when the suppression of self‐stimulation was discontinued, the per cent of self‐stimulation and that of appropriate play approached their presuppression levels. These results seem particularly significant because they identify a set of conditions under which spontaneous appropriate behavior, uncommon in autistic children, occurs at an increased level.

Two pigeons were exposed to a multiple schedule of reinforcement: in the presence of one discriminative stimulus, key pecks produced grain according to a fixed‐ratio schedule; Final Acceptance in the presence of a second discriminative stimulus, key pecks produced grain according to a variable‐ratio schedule. The key‐peck requirements in the two components were increased in successive stages from 50 to 125 responses. Live target pigeons were restrained at the rear of the chamber. Attacks against the targets were automatically recorded, and a variety of measures of attack behavior were taken. Attacks, when they occurred, always followed grain presentation. All measures revealed higher levels of attack during the fixed‐ratio component at all parameter values. All measures generally increased with increases in fixed‐ratio values with both birds, and with increases in variable‐ratio values with one bird. With the other bird, only the per cent of reinforcements followed by attack increased with increases in variable‐ratio value; Final Acceptance all other measures first increased and then decreased. Both increasing and bitonic functions relating induced attack to schedule parameters have been reported in experiments usually employing a single measure of attack. The measures have varied widely among these experiments. It is suggested that further studies of induced attack examine a wider range of schedule parameters and that relationships among measures be studied.

The key pecking of pigeons was reinforced according to a variable‐interval 1‐min schedule during each of two successively presented stimuli. When the key was illuminated by a black line on a white background, reinforcement was delayed for 10 sec. When the key was illuminated by a plain white light, reinforcement was not delayed. For half of the subjects, the delayed reinforcer was 4.0‐sec access to mixed grain, and for the remaining subjects it was 1.5‐sec access. The immediate reinforcer was 1.5‐sec access for all subjects. All subjects responded at a lower rate during the presentation of the black line; no between‐group difference in terms of terminal response rate during the presentation of the line was found. However, subjects that received 4.0 sec of delayed reinforcement responded at a lower terminal rate during presentation of the plain white light than subjects that received 1.5 sec of delayed reinforcement. A subsequent generalization test along the line‐orientation dimension produced flatter U‐shaped gradients for subjects that received 4.0‐sec of delayed reinforcement.

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Lever pressing in rats was reinforced with food under a multiple spaced‐responding schedule. A lever, food cup, and drinking tube were mounted in a running wheel so that lever pressing, running, and licking could be recorded. Running and licking had no scheduled consequences. Lever pressing was reinforced under a multiple schedule with three spaced‐responding components and an extinction component. Each component was associated with a different auditory stimulus. Spaced‐responding components reinforced only lever presses terminating interresponse times equal to or greater than 10, 20, or 60 sec, respectively. Rates of lever pressing, reinforcement, and licking all decreased as schedule parameter increased. Efficiency of spaced responding, as measured by reinforcements per response, also decreased. Rate of wheel running either increased or increased and then decreased with increasing schedule parameter. Individual running rates differed substantially. Neither licking nor running rate correlated with individual differences in efficiency. Analysis of conditional probabilities among the several response classes showed that, as the schedule requirement increased, the probability of running after a lever press increased and the probability of licking after a lever press decreased. After reinforcement, one subject always pressed the lever next. In the other subjects, the conditional probability of lever pressing, given reinforcement, increased while the probability of licking, given reinforcement, decreased with increasing schedule requirement. Results are discussed in relation to the concepts of schedule‐induced and mediating behavior.