The blocking of reinforcement control

Two experiments were conducted to extend the blocking effect to the reinforcement of a response. A delayed reinforcement contingency was presented to subjects with or without a previously pretrained response available during the delay interval. The interpolated response had no scheduled effect on delivery of the reinforcer, but its availability reduced strengthening of the initial response, which completely extinguished for some subjects. The results were interpreted as support for blocking as a fundamental principle of behavior, and as evidence against the principle of reinforcement being stated solely in terms of temporal proximity between response and reinforcer.     

Control of myoelectrical responses through reinforcement

A classic experiment by Hefferline, Keenan, and Harford (1959) showed that small thumb-twitches, imperceptible to the subject, can be controlled by the consequences of terminating and/or postponing aversive noise. These findings were further investigated in three experiments reported here. Experiment 1 replicated the original study. Experiment 2 was a control study in which stimulus changes were presented as in Experiment 1, but independently of the responses. Under these conditions the response rate varied over a large range with no systematic relation to experimental events. The increments in response rate reported by Hefferline et al. were within the present range of variation, suggesting that conditioning in the earlier study may have reflected a consistency in the direction of change rather than an increase in rate beyond the baseline range. In the present experiment, however, the rate increase was absolute. In Experiment 3, analog rather than binary changes in stimulus conditions were used as reinforcement. Under these conditions, the rates of subjects whose responses were conditioned fell from 78% (in the previous experiment) to 31%.     

Development of verbal control over bizarre gestures of retardates through imitative and nonimitative reinforcement procedures

Two retardates, manifesting hand gestures and minimal instructional control, were trained by imitative reinforcement procedures to imitate a response that was in contrast to gesturing. Next, with the contrast response continuing to be imitatively reinforced, gesturing was reduced by nonimitative reinforcement procedures; while providing facial and gesture cues, the adult said, "Do not do this". Imitative and nonimitative procedures were found to have the same effects on the contrast response as on the gesturing response, such that imitative procedures increased both responses, whereas nonimitative procedures decreased both. Nonperformance of gesturing was further maintained when (1) explicit verbal directions for nongesturing were superimposed upon the demonstrational-facial-verbal cues as these collective stimuli were faded out and (2) food reinforcers for nongesturing were gradually removed while social consequences continued to be administered.     

The effects of extinction,noncontingent reinforcement and differential reinforcement of other behavior as control procedures

Several techniques have been used in applied research as controls for the introduction of a reinforcement contingency, including extinction, noncontingent reinforcement (NCR), and differential reinforcement of other behavior (DRO). Little research, however, has examined the relative strengths and limitations of these "reversal" controls. We compared the effects of extinction with those of NCR and DRO in both multi-element and reversal designs, with respect to (a) rate and amount of response decrement, (b) rate of response recovery following reintroduction of reinforcement, and (c) any positive or negative side effects associated with transitions. Results indicated that extinction generally produced the most consistent and rapid reversal effects, with few observed negative side effects.     

Stimulus control with fixed-ratio reinforcement

Pigeons were trained on a three-stimulus simultaneous discrimination with reinforcements given on fixed-ratio schedules ranging from one response per reinforcement to 205 responses per reinforcement. Responses to any of the three stimuli advanced the ratio, but, when it was completed, a reinforcement followed a response to one designated stimulus. Throughout the ratio, the birds responded mainly to the designated stimulus. The relatively few responses to the other stimuli usually occurred immediately after postreinforcement pauses. The distribution of responses to the various stimuli was not affected by omitting reinforcements.     

Stimulus control and delayed reinforcement

Pigeons were tested for generalization along the line-orientation dimension, after being trained on various two-component multiple schedules. The first component contained either a variable-interval 1-min schedule of immediate reinforcement or an extinction schedule and was associated with a plain white key (S1). The second component contained a variable-interval 1-min schedule of delayed reinforcement and was associated with a black line on a white background (S2). The major results showed that (a) decremental gradients were obtained around the stimulus associated with the delayed reinforcement component when S1 was associated with extinction, but that incremental gradients were obtained when S1 was associated with immediate reinforcement, (b) the subjects' pretraining did not affect the generalization gradients if sufficient training on the terminal multiple schedule was provided, and (c) changing the S1 schedule from immediate reinforcement to extinction produced behavioral contrast if reinforcement was delayed for 10 sec during S2, but not if it was delayed for 20 sec.     

A review of reinforcement control procedures

A demonstration of the effects of reinforcement requires comparison of response rates in the presence of a contingency with those in another condition that controls for the influence of extraneous variables. We describe several control conditions that have been used in evaluating the effects of positive and negative reinforcement. The methodological rigor and practical utility of each type of control condition are discussed, and recommendations for the use of these conditions are presented.     

The operant conditioning of conversation

Human conversation is a natural place to begin the study of social responses. In a conversation, a number of individuals use one another's responses as cues for their own behavior. So long as a conversation is being held, the speakers must talk in some order. Four experiments were conducted to test whether differentially reinforcing a group of speakers can bring the order of speakers under experimental control. The results are all consistent with the hypothesis. The paper also devises and evaluates different procedures for studying conversational sequences and examines associated statistical problems.     

The role of locus of control of reinforcement in interpersonal attraction

The purpose of the present study was to examine initial interpersonal attraction as a function of locus of control orientation. Subjects, previously tested for internality and externality, listened to a tape of an alleged stranger of the same age and sex as the subject. In reality the tapes were prepared to be either primarily internal or external in emphasis. Subjects were then asked to make some judgments about the supposed stranger. Among these judgments was the degree of attraction felt toward the individual on the tape. It was hypothesized that similarity of locus of control orientation between a subject and a stranger would lead to greater initial attraction than would a complementary locus of control orientation. Contrary to prediction, the results showed that both internal and external subjects were significantly more attracted to an internal stranger than to an external stranger. These results were discussed within an interpersonal attraction framework which suggested the need for a two-factor theory as the basis for interpersonal attraction.     

Probability of reinforcement and the development of stimulus control

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.     

The establishment of stimulus control by instructions and by differential reinforcement

A repeated acquisition design was used to study the effects of instructions and differential reinforcement on the performance of complex chains by undergraduates. The chains required responding on a series of keys that corresponded to characters that appeared on a monitor. Each day, subjects performed a new chain in a learning session and later relearned the same chain in a test session. Experiment 1 replicated previous research by showing that instructional stimuli paired with the correct responses in the learning sessions, combined with differential reinforcement in both learning and test sessions, resulted in stimulus control by the characters in each link. Experiment 2 separated the effects of instructional stimuli and differential reinforcement, and showed that stimulus control by the characters could be established solely by differential reinforcement during the test sessions. Experiment 3 showed that when a rule specified the relation between learning and test sessions, some subjects performed accurately in the test sessions without exposure to any differential consequences. This rule apparently altered the stimulus control properties of the characters much as did differential reinforcement during testing. However, compared to differential reinforcement, the rule established stimulus control more quickly.     

Inhibitory stimulus control and the magnitude of delayed reinforcement

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.