Preconditioning of reinforcing properties to an exteroceptive feedback stimulus

Three groups of rats were given Pavlovian preconditioning by means of a yoking procedure and subsequently trained to avoid. One group received a light stimulus during preconditioning at the same times as the master avoiding animals received an exteroceptive feedback stimulus. During the subsequent avoidance training, this group was then given the same light stimulus as a feedback stimulus on successful avoidance trials. The group learned two-way avoidance in about the same number of trials as one-way avoidance is typically learned and substantially faster than two other control groups. These data indicate that feedback stimuli develop reinforcing properties by a Pavlovian mechanism. The data of the control groups indicate that feedback stimuli do not provide “information” about responding in the present situation.     

The effect of light intensity when onset or termination of illumination is used as reinforcing stimulus

The Psychological Record - Two experiments were performed to examine the reinforcing effects of onset and termination of non-aversive illumination, made conterminous with lever contacting, as a...     

A comparison of several procedures for eliminating behavior

The pecking response of pigeons was reinforced when a minimum period of time had elapsed since the last response (DRL schedule of food-reinforcement). Punishment, satiation, extinction, and stimulus change were employed separately to reduce responding. When the effects of the four procedures were compared, punishment was found capable of producing a more immediate, complete and long lasting response reduction than the others. Punishment had its maximum effect on the responses that were least relevant to reinforcement. The punishment reduced the frequency of the short inter-response times to a greater extent than did either extinction or satiation. In this way, punishment actually increased the efficiency of the DRL responding.     

Effects of stimulus variation on the reinforcing capability of nonpreferred stimuli

We examined the effects of stimulus (reinforcer) variation in several different contexts. In Study 1, we identified high-quality (HQ) and low-quality (LQ) stimuli based on results of a paired-stimulus assessment and examined their effects when available under concurrent-reinforcement schedules for 8 participants. No participants showed preference for the LQ stimuli when compared singly or in a varied arrangement to the HQ stimulus. In Study 2, we identified nonpreferred (NP) stimuli based on results of a single-stimulus assessment and examined their effects when available under single-reinforcement schedules for 3 participants. Results of Study 2 were mixed. One participant's data indicated that the varied presentation of NP stimuli produced a modest improvement in performance over that observed when the stimuli were presented singly. By contrast, a second participant's data showed no facilitative effect for the varied delivery of NP stimuli and that the inclusion of an HQ stimulus in the varied arrangement obscured the reinforcing effects of the HQ stimulus. The 3rd participant's data showed no effect for the varied delivery of NP stimuli but an apparent facilitative effect when an HQ stimulus was included in the varied arrangement, which was attributable solely to the presence of the HQ stimulus.     

Temporal summation related to the nature of the proximal stimulus for the warmth sense

Magnitude estimations of the warmth aroused by radiant stimulation of the forehead showed that warmth obeys the psychophysical power law when the’ duration of the stimulus is relatively long (3 or 6 sec). When duration is short (0.25, 0.5. or 1 sec), however, warmth grows as a more complex function of irradiation. The family of psychophysical functions measured for the various durations can be used to generate the rules by which radiant intensity and duration trade to preserve constant warmth. These rules vary systematically from complete temporal summation (i.e., complete reciprocity) near threshold to less and less complete summation as warmth level increases. When, however, the stimulus is expressed as an equivalent change of temperature in the skin, there is no summation, only adaptation. It can be shown that temporal summation observed psychophysically must result from the heat-transfer properties of skin tissue.     

The reinforcing value of several types of aggressive behavior: A review

Field observations of “surplus killing” and laboratory studies of operant performance rewarded by prey-killing opportunities suggest that predatory behavior is positively reinforcing. Similarly, both repeated encounter and operant performance studies suggest that intraspecific aggression can be positively reinforcing for successful aggressors. While a few studies suggest that defensive aggression under aversive conditions may also be positively reinforcing, it appears that when appropriate response modes are available escape and/or avoidance are preferred to attack. Studies of the reinforcing properties of aggression-eliciting brain stimulation are in general agreement with these conclusions, but methodological problems with these latter observations render them less compelling. The progressive escalation of aggression seen in “warm-up effects” of birds and fish, “priming effects” of mice, and ecstatic violence of humans may be analogous processes based on the positively self-reinforcing characteristics of some kinds of aggression. The transient reductions of aggression which appear as refractory periods and satiation effects in a variety of species may reflect temporary reductions in the reinforcing value of aggression. All these temporal effects must be considered in the evaluation of experiments on the reinforcing value of aggression. More generally, it is possible that these temporal fluctuations reflect the operation of common motivational processes (aggressive states) which regulate overt aggression by changing its reinforcing value.     

The effects of electroconvulsive shock on the action of a reinforcing stimulus

Three experiments sought to evaluate the effect of electroconvulsive shock on the action of a reinforcing stimulus. In all experiments behavior was maintained on a 2 min variable interval schedule for food reinforcement. Foot shock at the termination of a buzzer stimulus served as the reinforcing stimulus for conditioned suppression during the ensuing buzzer interval. Omission of foot shock at the termination of the buzzer stimulus was followed by normal responding (no conditioned suppression) during the next buzzer interval. In Exp I electroconvulsive shock followed foot shock at varying time intervals. In the first subsidiary experiment electroconvulsive shock followed an unreinforced buzzer stimulus at varying time intervals. In the second subsidiary experiment electroconvulsive shock followed foot shock at varying time intervals and an additional buzzer stimulus was sounded between the termination of foot shock and the onset of electroconvulsive shock. These three experiments demonstrated that electroconvulsive shock invariably abolished the effects of the reinforcing stimulus if it followed conditioning by no more than 10.0 sec and never had an effect if it followed conditioning by 12.5 sec or more; electroconvulsive shock was not acting as a reinforcing stimulus in this situation.     

A test of the reinforcing properties of stimuli correlated with nonreinforcement

The information hypothesis of conditioned reinforcement predicts that a stimulus that “reduces uncertainty” about the outcome of a trial will acquire reinforcing properties, even when the stimulus reliably predicts nonreinforcement. Four pigeons' key pecks produced one of two 5-sec stimuli with 0.50 probability according to a discriminated variable-interval schedule. One stimulus was followed by reinforcement; a second stimulus was followed by blackout. To the same extent, therefore, both stimuli reduced uncertainty about the possibility that food would arrive at the termination of the schedule interval. When a second key in the chamber was lighted, each peck on it could produce the stimulus preceding reinforcement, the stimulus preceding nonreinforcement, a novel stimulus, or no stimulus, across separate conditions. The stimulus preceding food maintained responding at substantial levels on the second, stimulus-producing, key. Such responding was not maintained by other stimuli. These data, replicated when the stimuli were reversed on the variable-interval schedule, do not support the prediction that uncertainty-reducing stimuli are necessarily conditioned reinforcers.     

A note on some reinforcing properties of university lectures

Contingency management systems in university courses have sometimes assigned the role of reinforcing stimulus to lectures and demonstrations. Attending a lecture was made contingent upon having previously finished certain course assignments. The present paper investigated some variables that control student attendance at lectures. Attendance remained high throughout each course at those class meetings where quizzes contributing to course grades were given or where impending quizzes were discussed. Attendance at lectures over the reading assignments or over material unrelated to course quizzes rapidly declined. When students were given course credit for attending these lectures, or when the lectures included information for future quizzes, attendance increased. When attending these lectures was made contingent upon having completed certain assignments the prior week, no increase in assignment completion was noted and the attendance at the lectures decreased even further. All lectures were given during one class meeting each week. Attendance at the other class meetings during the week remained stable.     

A comparison of verbal and tangible stimulus preference assessments

Tangible preference assessments were compared with verbal preference assessments for 6 individuals with mental retardation, behavior disorders, or both. In the tangible assessment, items were placed in front of the participant. In the verbal assessment, participants were asked, “Do you want X or Y?” and the items were not present. The two assessments yielded similar high‐preference items for 4 of the 6 participants. The verbal assessment was typically completed in less time than the tangible assessment.     

Concurrent schedules of response-independent reinforcement: duration of a reinforcing stimulus

Presentations of grain to three pigeons were determined by two response-independent schedules. Interpresentation intervals varied with a mean interval of 1.5 min for each schedule. Both were concurrently operative, but grain was presented by one only when the chamber was illuminated with blue light and by the other only during amber illumination. A response on a white key, the only key in the chamber, alternated the stimulus conditions and the effective schedule. Grain presentation durations associated with the illumination conditions were varied from 1.5 to 4.5 sec. The proportion of the total session time spent in an illumination condition closely approximated the relative grain presentation duration provided in that illumination. For two of the birds, the proportion of the total number of grain presentations obtained in an illumination condition was an increasng function of the presentation duration in that illumination.