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Results for “Reinforcement Schedule”

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At least 577 records · Page 32Linked to original sources

PubMed2001

Second-order schedules of token reinforcement with pigeons: effects of fixed- and variable-ratio exchange schedules.

Pigeons' key pecks produced food under second-order schedules of token reinforcement, with light-emitting diodes serving as token reinforcers. In Experiment 1, tokens were earned according to a fixed-ratio 50 schedule and were exchanged for food according to either fixed-ratio or variable-ratio exchange schedules, with schedule type varied across conditions. In Experiment 2, schedule type was varied within sessions using a multiple schedule. In one component, tokens were earned according to a fixed-ratio 50 schedule and exchanged according to a variable-ratio schedule. In the other component, tokens were earned according to a variable-ratio 50 schedule and exchanged according to a fixed-ratio schedule. In both experiments, the number of responses per exchange was varied parametrically across conditions, ranging from 50 to 400 responses. Response rates decreased systematically with increases in the fixed-ratio exchange schedules, but were much less affected by changes in the variable-ratio exchange schedules. Response rates were consistently higher under variable-ratio exchange schedules than tinder comparable fixed-ratio exchange schedules, especially at higher exchange ratios. These response-rate differences were due both to greater pre-ratio pausing and to lower local rates tinder the fixed-ratio exchange schedules. Local response rates increased with proximity to food under the higher fixed-ratio exchange schedules, indicative of discriminative control by the tokens.

Animals↗

PubMed2006

Influence of temporal context on value in the multiple-chains and successive-encounters procedures.

This set of studies explored the influence of temporal context across multiple-chain and multiple-successive-encounters procedures. Following training with different temporal contexts, the value of stimuli sharing similar reinforcement schedules was assessed by presenting these stimuli in concurrent probes. The results for the multiple-chain schedule indicate that temporal context does impact the value of a conditioned reinforcer consistent with delay-reduction theory, such that a stimulus signaling a greater reduction in delay until reinforcement has greater value. Further, nonreinforced stimuli that are concurrently presented with the preferred terminal link also have greater value, consistent with value transfer. The effects of context on value for conditions with the multiple-successive-encounters procedure, however, appear to depend on whether the search schedule or alternate handling schedule was manipulated, as well as on whether the tested stimuli were the rich or lean schedules in their components. Overall, the results help delineate the conditions under which temporal context affects conditioned-reinforcement value (acting as a learning variable) and the conditions under which it does not (acting as a performance variable), an issue of relevance to theories of choice.

Animals↗

PubMed1998

Using a self-control training procedure to increase appropriate behavior.

The present study evaluated a technique for teaching self-control and increasing desirable behaviors among adults with developmental disabilities. Results showed that when participants were initially given the choice between an immediate smaller reinforcer and a larger delayed reinforcer, all participants repeatedly chose the smaller reinforcer. Concurrent fixed-duration/progressive-duration reinforcement schedules then were introduced in which initially both the smaller and larger reinforcers were available immediately. Thereafter, progressively increasing delays were introduced for the schedule associated with the larger reinforcer only. When initial short-duration requirements for access to the larger reinforcer were gradually increased, participants repeatedly selected the larger reinforcer, thereby demonstrating increased self-control.

Adult↗

PubMed1996

Human behavioral momentum: implications for applied behavior analysis and therapy.

Recent behavioral studies have addressed the persistence of behavior under altered environmental conditions using more sophisticated techniques of behavior analysis which have direct relevance for applied behavior analysis and therapy. In clinical populations, for example, behavioral programs are concerned with issues such as generalizability of behavior and relapse prevention (Epstein, 1992). Free-operant behavior can be analyzed not only in terms of its response rate but also in terms of its persistence under changed environmental constraints. The aggregation of these two response measures, rate and persistence, has been termed behavioral momentum (Nevin, Mandell, & Atak, 1983). This study assessed behavioral momentum in a human population in order to test predictions made from the behavioral model and potential clinical applications of behavioral momentum to behavior analysis and therapy. Eight undergraduates served as subjects for this study. Results were consistent with the predictions based on behavioral momentum. Denser reinforcement schedules, regardless of response contingency, produced greater resistance to the implementation of changed contingency schedules. Results of this study may have direct application to behavior analysis programs. If humans, in clinical contexts, show similar patterns of persistence in behavior under changed environmental settings, schedules could be implemented that provide both contingent and non-contingent reinforcement, thereby strengthening behavior to give it greater generalizability outside of the immediate situation.

Adult↗

PubMed1982

Acquisition and extinction of continuously and partially reinforced running in rats with lesions of the dorsal noradrenergic bundle.

Local injection of 6-hydroxydopamine was used to selectively destroy the dorsal ascending noradrenergic bundle (DB) in rats. Two lesion procedures were used, differing in the extent of depletion of forebrain noradrenaline they produced (greater than 90% or 77%). In Experiments 1-3 the rats were run in a straight alley for food reward on continuous (CR) or partial (PR) reinforcement schedules. The smaller lesion reduced and the larger lesion eliminated the partial reinforcement acquisition effect (i.e. the faster start and run speeds produced by PR during training) and the partial reinforcement extinction effect (PREE, i.e. the greater resistance to extinction produced by PR training); these changes were due to altered performance only in the PR condition. Abolition of the PREE by the larger DB lesion occurred with 50 acquisition trials, but with 100 trials the lesion had no effect. In Experiment 4 rats were run in a double runway with food reward on CR in the second goal box, and on CR, PR or without reinforcement in the first. The larger lesion again eliminated the PREE in the first runway, but did not block the frustration effect in the second runway (i.e. the faster speeds observed in the PR condition after non-reward than after reward in the first goal box). These results are consistent with the hypothesis that DB lesions alter behavioural responses to signals of non-reward, but not to non-reward itself. They cannot be predicted from two other hypotheses: that the DB mediates responses to reward or that it subserves selective attention. Since septal and hippocampal, but not amygdalar, lesions have been reported to produced similar behavioural changes, it is proposed that the critical DB projection for the effects observed in these experiments is to the septo-hippocampal system.

Animals↗

PubMed1977

Research on the difference between generalization and maintenance in extra-therapy responding.

Many authors have reported that the development of programs for producing durable extra-therapy responding lags behind the development of programs for producing initial behavior change. In Experiment I, responding was recorded continuously in both the therapy and extra-therapy settings. The results showed that one child did not generalize to the extra-therapy setting, but that other children did. However, for the children who generalized, extra-therapy responding was not maintained. Therfore, in Experiment II two variables affecting the durability of extra-therapy responding were assessed and found to be influential: (a) the use of partial reinforcement schedules in the original treatment environment; and (b) the presence of noncontingent reinforcers in the extra-therapy environment. The results suggest that there are two distinct parameters of extra-therapy responding: generalization and maintenance. A technology for producing durable extra-therapy responding is discussed in terms of different treatment procedures required for different deficits in extra-therapy responding.

Autistic Disorder↗

PubMed1976

Concurrent performances: rate constancies without changeover delays.

Pigeons' pecks on two keys were maintained, without changeover delays, by independent variable-interval schedules of food reinforcement. Four regularly cycling 2-min components scheduled reinforcement respectively for both keys, left key only, both keys, and right key only. Initially, reinforcement scheduled for one key alone produced more responding on that key than reinforcement scheduled concurrently for both keys. Continued sessions reduced this difference; response rate on a given key approached constancy, or invariance with respect to the performance on and schedule for the other key. When extinction replaced the reinforcement schedule on either key, responding on that key decreased more during components that scheduled reinforcement for the other key than during those that did not. This demonstration that responses on one key were not supported by reinforcers on the other key suggested that the alternation of concurrent responding and either-key-alone responding prevented concurrent superstitions from developing.

Journal Article↗

PubMed1970

Schedule-induced aggression as a function of fixed-ratio value.

Pigeons responding for food on fixed-ratio reinforcement schedules attacked live target birds when the ratio value was increased, but not when the value was decreased. The frequency of attacks peaked several days after ratio value change, and then gradually decreased to an original level.

Aggression↗

PubMed1983

Choice between response units: The rate constancy model.

In a conjoint schedule, reinforcement is available simultaneously on two or more schedules for the same response. The present experiments provided food for key pecking on both a random-interval and a differential-reinforcement-of-low-rate (DRL) schedule. Experiment 1 involved ordinary DRL schedules; Experiment 2 added an external stimulus to indicate when the required interresponse time had elapsed. In both experiments, the potential reinforcer frequency from each component was varied by means of a second-order fixed-ratio schedule, and the DRL time parameter was changed as well. Response rates were described by a model stating that time allocation to each component matches the relative frequency of reinforcement for that component. When spending time in a given component, the subject is assumed to respond at the rate characteristic of baseline performance. This model appeared preferable to the absolute-rate version of the matching law. The model was shown to be applicable to multiple-response concurrent schedules as well as to conjoint schedules, and it described some of the necessary conditions for response matching, undermatching, and bias. In addition, the pigeons did not optimize reinforcer frequency.

Journal Article↗

PubMed1980

Extinction and dopamine receptor blockade after intermittent reinforcement training: failure to observe functional equivalence.

Response decrements in an operant task produced by either extinction or by the dopamine receptor blocker pimozide were examined in three experiments which employed intermittent reinforcement schedules. In contrast to the congruency between these treatments previously observed following continuous reinforcement training, treatment with pimozide was markedly more effective than extinction in decreasing performance after training with variable interval, fixed interval, and fixed ratio reinforcement. The two treatments also produced substantially different patterns of responding. A shift from extinction to pimozide did not alter the progressive decline in response rate over days, but a shift from pimozide to extinction caused a pronounced increase of performance. These results indicate that the pimozide and extinction treatment did not produce functionally equivalent effects, and that the role of dopamine on reward processes should not be inferred from comparisons between pimozide and extinction.

Animals↗

PubMed1978

Noradrenaline and partial reinforcement in rats.

Lesions of the dorsal nonadrenergic bundle produced by 6-hydroxydopamine, which depleted telencephalic noradrenaline by over 95%, were found to produce resistance to extinction in animals trained on a continuously reinforced schedule for food reward but not to alter the extinction rate after partial reinforcement training. These results confirm the dorsal bundle extinction effect reported previously but suggest that it is confined to continuously reinforced situations. The pattern of results is consistent with a role for the dorsal bundle in attentional processes but appears to contradict the predictions required if the dorsal bundle were to have a role in frustrative nonreward.

Animals↗

PubMed2001

Situational descriptions of behavioral procedures: the in situ testbed.

We demonstrate the In Situ testbed, a system that aids in evaluating computational models of learning, including artificial neural networks. The testbed models contingencies of reinforcement rising an extension of Mechner's (1959) notational system for the description of behavioral procedures. These contingencies are input to the model under test. The model's output is displayed as cumulative records. The cumulative record can then be compared to one produced by a pigeon exposed to the same contingencies. The testbed is tried with three published models of learning. Each model is exposed to up to three reinforcement schedules (testing ends when the model does not produce acceptable cumulative records): continuous reinforcement and extinction, fixed ratio, and fixed interval. The In Sitt testbed appears to be a reliable and valid testing procedure for comparing models of learning.

Animals↗

PubMed2005

Effects of delayed reinforcers on the behavior of an animal model of attention-deficit/hyperactivity disorder (ADHD).

Attention-deficit/hyperactivity disorder (ADHD), affecting 3-5% of grade-school children, is a behavioral disorder characterized by developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. It has been suggested that the symptoms are caused by altered reinforcement and extinction processes, behaviorally described as an abnormally short and steep delay-of-reinforcement gradient in ADHD. The present study tested predictions from the suggested shortened and steepened delay gradient in ADHD in an animal model, the spontaneously hypertensive rats (SHRs). It was predicted that SHR responding during baseline would mainly consist of responses with short inter-response times, and that responding would be more rapidly reduced in the SHR than in the controls by the introduction of a time interval between the response and reinforcer delivery. Effects of a resetting delay of reinforcement procedure with water as the reinforcer were tested on two baseline reinforcement schedules: variable interval 30 s (VI 30 s) and conjoint variable interval 60 s differential reinforcement of high rate 1s (VI 60 s DRH 1 s). The results showed a higher rate of responses in the SHR than in the controls during baseline, mainly consisting of responses with short inter-response times. The statistical analyses showed that response rates decreased more rapidly as a function of reinforcer delay in the SHR than in the controls. The analyses of the estimates of the reinforcer decay parameter showed no strain differences during the VI 30 s schedule but showed a significant strain difference at the end, but not at the start, of the sessions during the VI 60 s DRH 1 s schedule. In general, the results support predictions from the suggested steepened delay gradient in SHR. However, the predictions were only partly confirmed by the analyses of the decay parameter.

Analysis of Variance↗

PubMed1982

Failure to obtain functional equivalence between dopamine receptor blockade and extinction: evidence supporting a sensory-motor conditioning hypothesis.

The effects of pimozide were tested in a discrete trial paradigm. Following 8 days of continuous reinforcement training with a retractable bar, subjects were divided into 3 groups: Vehicle-Extinction; Pimozide-Extinction and Pimozide-Reinforcement. Pimozide rats received 1 mg/kg of drug 4 hours prior to test. On each of 3 test days reinforcement continued to be delivered on a continuous reinforcement schedule for the Pimozide-Reinforcement Group whereas it was no longer delivered for the other two groups. Each test day was separated by 4 drug-free days. The Pimozide-Reinforcement Group showed the least response suppression, followed by the Vehicle-Extinction and Pimozide-Extinction Groups. These results do not support the anhedonic hypothesis that dopamine containing neurons mediate reward processes and were interpreted within a sensory-motor conditioning framework.

Animals↗

PubMed2005

Moment-to-moment dynamics of ADHD behaviour.

BACKGROUND: The behaviour of children with Attention-Deficit/Hyperactivity Disorder is often described as highly variable, in addition to being hyperactive, impulsive and inattentive. One reason might be that they do not acquire complete and functional sequences of behaviour. The dynamic developmental theory of ADHD proposes that reinforcement and extinction processes are inefficient because of hypofunctioning dopamine systems, resulting in a narrower time window for associating antecedent stimuli and behaviour with its consequences. One effect of this may be that the learning of behavioural sequences is delayed, and that only short behavioural sequences are acquired in ADHD. The present study investigated acquisition of response sequences in the behaviour of children with ADHD. METHODS: Fifteen boys with ADHD and thirteen boys without, all aged between 6-9 yr, completed a computerized task presented as a game with two squares on the screen. One square was associated with reinforcement. The task required responses by the computer mouse under reinforcement contingencies of variable interval schedules. Reinforcers were cartoon pictures and small trinkets. Measures related to response location (spatial dimension) and to response timing (temporal dimension) were analyzed by autocorrelations of consecutive responses across five lags. Acquired response sequences were defined as predictable responding shown by high explained variance. RESULTS: Children with ADHD acquired shorter response sequences than comparison children on the measures related to response location. None of the groups showed any predictability in response timing. Response sequencing on the measure related to the discriminative stimulus was highly related to parent scores on a rating scale for ADHD symptoms. CONCLUSION: The findings suggest that children with ADHD have problems with learning long sequences of behaviour, particularly related to response location. Problems with learning long behavioural sequences may ultimately lead to deficient development of verbally governed behaviour and self control. The study represents a new approach to analyzing the moment-to-moment dynamics of behaviour, and provides support for the theory that reinforcement processes are altered in ADHD.

Journal Article↗

PubMed1979

Deviations from matching as a measure of preference for alternatives in pigeons.

Preferences for larger or smaller defined response classes were investigated in a concurrent schedule precedure. Twelve pigeons were run on a series of concurrent variable-interval reinforcement schedules, from which baseline matching functions were obtained. An experimental phase followed, in which a second response key was available in one concurrent schedule alternative. For half the birds, the second key was programmed identically with the first; for the other half, the added key was programmed for extinction, with position irrelevant. Comparison of baseline and experimental matching functions revealed no systematic changes in either slope or intercept for birds in the latter group.

Animals↗

PubMed1995

Effects of combined or separate 5,7-dihydroxytryptamine lesions of the dorsal and median raphe nuclei on responding maintained by a DRL 20s schedule of food reinforcement.

Previous studies have shown that long-term 5-hydroxytryptamine (5-HT) depletion induced by combined dorsal and median raphe injections of 5,7-dihydroxytryptamine (5,7-DHT) leads to impairments in the acquisition and performance of behaviour maintained under a differential-reinforcement-of-low-rate (DRL) schedule of reinforcement. The present studies examined the relative importance of dorsal versus median raphe 5-HT projections in mediating these effects by investigating the impact of separate versus combined infusions of 5,7-DHT into these sites on DRL responding. Adult male rats received injections of 3 micrograms 5,7-DHT into both dorsal raphe and median raphe, dorsal raphe only, or median raphe only. Sham-operated controls received vehicle injections. Animals were then trained to respond on a DRL 20s schedule for 36 days. Combined dorsal raphe and median raphe 5,7-DHT infusions depleted striatal and hippocampal 5-HT by > 90%, increased responding, decreased the number of reinforcers earned, lowered the mean inter-response time (IRT), and shifted the frequency distribution of IRTs to the left. Median raphe 5,7-DHT infusions induced similar behavioural effects and reduced hippocampal 5-HT by 64%. Dorsal raphe 5,7-DHT lesions, that depleted striatal 5-HT by 56%, and hippocampal 5-HT by 30%, had no effect on behaviour. In a final experiment it was shown that providing an external cue light to signal food availability, and that removed the need to rely on internal timing processes, resulted in rapid acquisition of responding, and prevented the behavioural deficits in 5,7-DHT-lesioned rats. Following removal of this cue, responding deteriorated, and the 5,7-DHT treated animals performed worse than controls. These results suggest that destruction of 5-HT neurons arising from the median raphe is sufficient to disrupt behaviour maintained by a DRL 20s schedule, and that the behavioural changes observed may involve a deficit in timing.

5,7-Dihydroxytryptamine↗

PubMed1986

Chlorpromazine and pimozide alter reinforcement efficacy and motor performance.

This study evaluated the effects of chlorpromazine and pimozide on reinforced responding. In each session, rats were exposed to a series of five variable-interval reinforcement schedules. The response requirement was a lever press, the reward was a small portion of water, and the reinforcement rate varied from about 20 to 660 reinforcers per hour. Response rate was a negatively accelerated function of reinforcement rate, and the relationship between the two variables was described by the equation for a rectangular hyperbola (the matching law). One parameter of the hyperbola is equivalent to the asymptotic response rate and the other parameter is equivalent to the rate of reinforcement that maintains a one-half asymptotic response rate. Chlorpromazine (0.75-3.0 mg/kg) and pimozide (0.1-0.4 mg/kg) dose-dependently decreased response rates. At low doses, the response rate decreases were, for the most part, restricted to the low reinforcement rate schedules. In contrast, the highest dose tested decreased response rates at both low and high reinforcement rates. The patterns of response rate decreases resulted in dose-dependent changes in the parameters of the matching law equation. The shifts in the matching law parameters were discussed in terms of the motoric and motivational interpretations of neuroleptic-induced response rate changes.

Animals↗