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A system called Performance Determined Instruction (PDI) is presented as a methodological tactic for training in remedial reading. The system incorporates aspects of binary logic, instrumental conditioning, and programmed instruction. Results suggest that PDI is a high‐precision instructional procedure effective in obtaining desired changes in reading‐task performance.

Rats were shocked every 6 min while responding was maintained on a variable‐interval schedule of reinforcement. With some rats, shocks were interspersed with a sequence of three different stimulus conditions (S3→S2→S1), or clock cues, each lasting 2 min. For other rats, a single stimulus condition prevailed between shocks at the beginning of the experiment and clock cues were introduced later. Response rate decreased from S3 to S1. Response rate in S3, S2, and S1 was inversely related to shock intensity. When clock cues were added, response rate increased in all 2‐min intershock periods. During clock cues, an index of curvature, indicating the degree of negative acceleration of response rate, was greatest for S1 and least for S3, and was directly related to shock intensity. The response‐facilitating effect of shock and its relation to a possible discriminative function of shock and to behavioral contrast is discussed.

A procedure in which responses reduced intermittently presented electric shocks to one quarter of their originally scheduled intensity, effectively engendered and maintained lever pressing in hooded rats. This contingency also markedly increased the response rates of rats initially trained under an unsignaled avoidance procedure. The responding of all animals extinguished rapidly when shock was withdrawn. Subsequently, it was discovered that high response rates could be maintained solely through presentation of shocks that were not affected by responses. Variations in the interval between shocks and changes in shock intensity over a wide range did not attenuate responding. Terminal performance was characterized by a consistent pattern of shock‐elicited responses. Responses were also elicited by a tone following repeated tone‐shock pairings. Finally, responding that was maintained by response‐independent shocks was quickly suppressed by response‐contingent shocks of the same intensity.

Research has revealed the phenomenon of conditioned suppression in which the rate of responding is reduced during a stimulus that is paired with noncontingent shock. The present study replicated this procedure, but used noncontingent positive reinforcers instead of the aversive shock. The lever‐pressing responses of rats were reinforced with food or water. While the rats were responding, a stimulus was occasionally presented and paired with the delivery of a noncontingent positive reinforcer, which was either food, water, or brain stimulation for different rats. The result was a reduction in the rate of responding during the conditioned stimulus. This finding shows that conditioned suppression occurs during a signal for reinforcing as well as aversive stimuli.

Pigeons were trained on a two‐link concurrent chain schedule in which responses on two keys were reinforced according to independent variable‐interval schedules by the production of a change in key color. Further responses on the key on which the stimulus change had been produced gave a single food reinforcement and a return to concurrent variable‐interval conditions. On one key the terminal link was a two‐valued mixed‐interval schedule, while on the other, the terminal link was a fixed‐interval schedule. When the mixed‐interval values were kept constant and the fixed‐interval values varied, relative response rates in the initial concurrent links matched relative reinforcement rates in the terminal links when these were computed from cubic transformations of the reciprocals of the intervals comprising the terminal link schedules.

Pigeons were trained with a successive discrimination procedure in which responding during the negative stimulus was never reinforced and responding during the positive stimulus was reinforced according to one of four probability values. This discrimination training followed extensive training with a single, neutral stimulus and the same temporal distribution of reinforcements. The development of stimulus control was studied by tracing the difference in rate of responding between the positive and negative stimuli over the course of discrimination training. Response rate during the positive stimulus remained constant, while that during the negative stimulus decreased to zero. The probability of reinforcement associated with the positive stimulus affected both the total number of responses emitted during the negative stimulus and the number of negative stimulus presentations during which responding occurred. However, the number of reinforcements during the positive stimulus preceding the attainment of various degrees of stimulus control was similar for all probability values.

Squirrel monkeys were restrained in a chair equipped with a tail‐shock apparatus and a pneumatic bite hose located in front of the subject's face. An aggressive response was recorded when the monkey bit the hose. Initial sessions in which no shocks were delivered produced some biting. When biting during these sessions stabilized at a near‐zero level, regularly scheduled shocks were delivered to the monkey's tail, causing a consistently higher rate of biting. After several sessions under these conditions, a punishment phase was introduced in which the previous shock conditions were maintained, and every bite was followed immediately by another, more intense shock. Biting under these conditions was suppressed to a near‐zero level. When the punishment contingency was removed, biting increased. With one subject, two additional bite‐contingent stimuli were examined: (1) a milder shock that, when made contingent upon hose biting, also suppressed that response, and (2) a contingent tone that had no obvious suppressing or facilitating effect. Individual differences among subjects were extreme, but the effect of bite‐contingent shock was consistent. Observations of the subjects during the punishment sessions indicated the existence of certain side effects that resulted from the use of punishment to suppress shock‐induced aggression.

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