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PubMedDate not supplied

Dependence of the electrical activity of the hippocampus on the probability of reinforcement of an alimentary conditional stimulus.

The dynamics of the changes in the number of instrumental motor reactions and in the frequency of cardiac contractions and of the theta rhythm of the hippocampus during the replacement of constant reinforcement by various schedules of probabilistic reinforcement of an alimentary conditional stimulus were investigated in three dogs. At the 70 and 50% level of reinforcement, the instrumental reflex appeared in response to all of the presentations of the signal stimulus. The greatest decrease in the number of respondent reactions was observed at 5% probability. The pulse rate both in the intersignal period and during the receipt of an empty feeder depended on the probability of reinforcement employed and on the individual characteristics of the animals. The frequency of the theta rhythm in all of the dogs was highest at the 30% level; the lowest values were observed at the 5% level of reinforcement. The data obtained again attest to the complex genesis of emotional excitation, the magnitude of which depends both on the informational (indeterminacy) and on the motivational (the significance of the reinforcement) factors.

Animals↗
PubMed1988

DSP4 and Herrnstein's equation: further evidence for a role of noradrenaline in the maintenance of operant behaviour by positive reinforcement.

The effect of the selective noradrenaline neurotoxin DSP4 on steady-state operant behaviour was examined using a quantitative behavioural paradigm based on Herrnstein's (1970) equation, which defines a hyperbolic relationship between steady-state response rate and reinforcement frequency in variable-interval schedules. Eleven rats received injections of DSP4 (two doses of 50 mg/kg, intraperitoneally), and 12 rats received injections of the vehicle alone. The rats were trained to steady state in a series of six variable-interval schedules of sucrose reinforcement, affording scheduled reinforcement frequencies of 4-360 reinforcers per hour. Herrnstein's equation was fitted to the data obtained from each rat and to the averaged data obtained from the two groups. The value of KH (the parameter expressing the reinforcement frequency needed to maintain the half-maximal response rate) was higher in the DSP4-treated rats than in the control rats; the value of Rmax (the parameter expressing the maximum response rate) did not differ significantly between the two groups. At the end of the behavioural experiment the rats were sacrificed for determination of the concentrations of catecholamines in the brain by high-performance liquid chromatography. The levels of noradrenaline in the parietal cortex, hippocampus and cerebellum of the DSP4-treated rats were less than 20% of those of the control rats. The results provide further evidence that central noradrenergic neurones are involved in the maintenance of operant behaviour by positive reinforcement.

Animals↗
PubMed1990

Reinforcing effects of a pentobarbital-ethanol combination relative to each drug alone.

The reinforcing effects of an orally delivered combination of 1 mg/ml pentobarbital plus 1% ethanol were evaluated in four rhesus monkeys. The drug combination and another liquid (either water, 1 mg/ml pentobarbital, or 1% ethanol) were concurrently available under identical fixed-ratio (FR) schedules. Substantially higher response rates were maintained by the drug combination than by any of the three other liquids. Thus, the reinforcing effects of the pentobarbital-ethanol combination were greater than those of either component drug. In a second experiment, water (the vehicle) was concurrently available with one other liquid (1 mg/ml pentobarbital, 1% ethanol, or the pentobarbital-ethanol combination). All three drug solutions functioned as reinforcers since they maintained much higher response rates than water. These results demonstrate that the greater relative reinforcing effects of the drug combination in the first experiment were not due to a lack of reinforcing effects of the 1 mg/ml pentobarbital or 1% ethanol solutions. In a final experiment, the drug combination was scheduled concurrently with 1 mg/ml pentobarbital, and FR size was systematically varied. The drug combination was then scheduled concurrently with 1% ethanol, and FR size was again varied. As FR size increased, the relative amount of responding maintained by the drug combination increased. Thus, differences in relative reinforcing effects that were evident in the first experiment were again evident in the final experiment when appropriate schedule-parameter values were used.

Administration, Oral↗
PubMed2004

Varying reinforcer duration produces behavioral interactions during multiple schedules.

The experiments tested the idea that changes in habituation to the reinforcer contribute to behavioral interactions during multiple schedules. This idea predicts that changing an aspect of the reinforcer should disrupt habituation and produce an interaction. Pigeons and rats responded on multiple variable interval variable interval schedules. Introducing variability into the duration of reinforcers in one component increased response rates in both components when the schedules provided high, but not low, rates of reinforcement. The increases in constant-component response rates grew larger as the session progressed. Within-session decreases in responding were smaller when the other component provided variable-, rather than fixed-, duration reinforcers. These results are consistent with the idea that changes in habituation to the reinforcer contribute to behavioral interactions. They help to explain why interactions do not occur for some subjects under conditions that produce them for others. Finally, the results question the assumption that induction and behavioral contrast are always produced by different theoretical mechanisms.

Animals↗
PubMedDate not supplied

The effects of fixed-time and contingent schedules of negative reinforcement on compliance and aberrant behavior.

Prior research has suggested that fixed-time (FT) schedules of reinforcement do not necessarily preclude the acquisition of appropriate behavior (e.g., mands) when combined with differential reinforcement (DRA). These studies also note that dense FT schedules are more likely to interfere with DRA packages than lean FT schedules. In the current investigation, we examined whether similar findings would occur with FT schedules of negative reinforcement. Schedule analyses were conducted with two participants following functional analyses that identified escape from task demands as the maintaining variable for problem behavior. Differential negative reinforcement of alternative behavior (DNRA) was implemented first to establish behavioral control (decreased problem behavior and increased compliance). Breaks (negative reinforcement) were then concurrently delivered on a FT basis under either dense (at a greater rate than that obtained during DNRA alone) or lean (at a lower rate than that obtained during DNRA) reinforcement schedules. In general, results showed that FT escape did not preclude compliance when the FT schedule was lean, but treatment gains were significantly disrupted when dense FT schedules were superimposed.

Attention Deficit and Disruptive Behavior Disorder↗
PubMedDate not supplied

Treating problem behaviors maintained by negative reinforcement.

The examination of controlling contingencies in an analysis of problem behavior has been an important clinical topic of discussion in the field of developmental disabilities for many years. We know that problem behavior may be maintained by positive reinforcement or by negative reinforcement. From a clinical perspective, we seem to know more about behavioral techniques that are used when the problem behavior is maintained by positive reinforcement that we understand about those techniques that may be applied when a problem behavior is maintained by negative reinforcement. In this paper, we identify four treatment techniques that may be applied when problem; behavior is maintained by negative reinforcement: (a) functional communication training; (b) behavioral momentum; (c) differential reinforcement or an alternative escape behavior; and (d) errorless learning. Each of the four techniques will be defined, applications and guidelines for use delineated.

Adult↗
PubMed2006

Pharmacological determinants of the reinforcing effects of psychostimulants: relation to agonist substitution treatment.

Illicit use of psychostimulants, such as cocaine and methamphetamine, continues to pose a significant public health concern. On the basis of the relative success at treating opiate and tobacco users with agonist substitution treatments, this strategy has been pursued in the search for a pharmacotherapy for psychostimulant addiction. The reinforcing effects of drugs are central to their abuse liability; therefore, gaining a better understanding of the factors that determine the reinforcing effects of psychostimulants should inform the development of an effective treatment. Although the reinforcing effects of drugs are known to be multiply determined, the author's dissertation research focused on pharmacological factors. This review presents results from that research as well as findings reported in the extant literature, suggesting that the reinforcing effects of psychostimulant drugs are determined both by their pharmacodynamic and pharmacokinetic profiles. There is evidence to support the conclusion that affinity for dopamine transporters appears to be of critical importance, whereas serotonin transporters seem to serve a modulatory function. A more rapid rate of onset may enhance a drug's reinforcing effects, but a drug with a slow onset can still maintain self-administration. A drug's duration of action may only influence the rate but not the strength of responding that is maintained. Slow-onset, long-acting monoamine transporter ligands can be expected to have reinforcing effects and therefore abuse liability, which has implications for the use of these drugs as pharmacotherapies. Nonetheless, on the basis of promising preclinical and clinical findings, this appears to represent a viable treatment strategy.

Central Nervous System Stimulants↗
PubMed2003

Attenuation of sucrose reinforcement in dopamine D1 receptor deficient mice.

Dopaminergic systems are thought to mediate the rewarding and reinforcing effects of palatable food. However, the relative contribution of different dopamine receptor subtypes is not clear. We used dopamine D1 receptor deficient mice (D1 -/-) and their wild-type and heterozygous littermates to study the role of the D1 receptor in palatable food reinforced behaviour using operant responding and free access paradigms. Non-deprived mice were trained to press a lever for sucrose pellets under three schedules of reinforcement including fixed ratios (FR-1 and FR-4) and a progressive ratio (PR). Responding on one lever was reinforced by the delivery of a sucrose pellet or solution while responding on a second lever had no programmed consequences. Initially, D1 mutant mice took longer to learn to discriminate between the two levers and had significantly lower operant responding for sucrose pellets and solution than wild-type and heterozygous mice under all schedules of reinforcement. Food deprivation enhanced responding on the active lever in all mice although it remained significantly lower in D1 -/- mice than in control mice. Following extinction of sucrose reinforcement and reversal of the levers, D1 -/- mice showed deficits in extinguishing and reversing previously learned responses. Home cage intake and preference of sucrose pellets and solutions when given under free-choice access paradigms were similar among the groups. These results suggest that the dopamine D1 receptor plays a role in the motivation to work for reward (palatable food) but not in reward perception and is critical in learning new but relevant information and discontinuing previously learned responses.

Analysis of Variance↗
PubMed2005

Responding for sucrose and wheel-running reinforcement: effect of D-amphetamine.

The present study assessed the effect of D-amphetamine on responding maintained by wheel-running and sucrose reinforcement. Six male albino Wistar rats were placed in running wheels and exposed to a fixed-interval 30-s schedule that produced either a drop of 5% sucrose solution or the opportunity to run for 15 s as reinforcing consequences for lever pressing. Each reinforcer type was signaled by a different stimulus. Doses of 0.25, 0.5, 1.0, 1.5, and 3.0 mg/kg D-amphetamine were administered by i.p. injection 20 min prior to a session. As the dose increased, index of curvature values decreased toward zero and rate-dependency plots revealed increases in lower rates early in the interval and decreases in higher rates toward the end of the interval. Effects were similar in the presence of both stimuli. However, an analysis of post-reinforcement pauses and local response rates broken down by transitions revealed a differential effect. As the dose increased, local response rates following a wheel-running reinforcer were affected more than those following a sucrose reinforcer.

Animals↗
PubMed1991

Establishing operations and reinforcement effects.

Positive reinforcement procedures have had a major impact on educational programs for the developmentally disabled; nevertheless, variation in reinforcer effectiveness both within and across individuals is a common phenomenon. This study examined one class of variables--establishing operations--that might influence the effectiveness of reinforcers. Five developmentally disabled adult males participated. Responding on one of two motor tasks--switch closure or block placement--was assessed during baseline, satiation, and deprivation conditions with respect to three classes of consequences: small food items, music, and social praise. Deprivation and satiation conditions were constructed so as not to alter significantly the normal course of events in a subject's day. For example, food deprivation entailed scheduling sessions just prior to a subject's regular lunch, and social deprivation involved limiting a subject's access to social interaction for 15 minutes, during which time the subject had access to an assortment of other activities. Results showed that each stimulus class functioned as reinforcement with different degrees of effectiveness during satiation versus deprivation conditions. These results are discussed in light of previous research on enhancement of reinforcer efficacy as well as the assessment and identification of functional reinforcers, and implications are presented for future research and client habilitation.

Adult↗
PubMed1997

Evaluation of the "control over reinforcement" component in functional communication training.

The effectiveness of functional communication training (FCT) as a treatment for behavior disorders has been attributed to a number of variables, one of which is the individual's ability to exert control over the delivery of reinforcement. We evaluated this component of FCT by exposing individuals to conditions in which their behavior either did or did not affect the delivery of reinforcement. Three adults with mental retardation who engaged in self-injurious behavior (SIB) participated. Following a functional analysis of their SIB, the effects of FCT were compared to those of noncontingent reinforcement (NCR) in a multielement design. The amount of reinforcement during both conditions was equated by yoking the schedule of reinforcement during NCR sessions to that in effect during FCT sessions. Results indicated that FCT and NCR were equally effective in reducing the SIB of all participants and suggest that control over reinforcement delivery may not affect the degree to which FCT produces behavioral suppression. However, a different benefit of FCT was evident in the results: More consistent increases in the alternative response were observed during the FCT condition than during the NCR condition.

Adult↗
PubMed1963

Rate differential reinforcement in monkey manipulation.

A set of four manipulanda were presented to four Cebus monkeys, individually, and later in pairs. Step 1 provided an estimate of each S's probability of operating each item, while Step 2 determined whether pairing the items would disturb the ordinal relations among individual response probabilities. Both procedures provided information necessary for testing the assumption that a reinforcer is simply a contingent response whose independent probability of occurrence is greater than that of the associated instrumental response. Step 3 tested this assumption by again presenting pairs of items, but with one locked and its operation made contingent upon operation of the free item of the pair. The four Ss differed markedly in the extent to which the items produced different independent response probabilities, and correspondingly, in the extent to which the contingent pairs subsequently produced reinforcement. Confirmation of the present assumptions came primarily from one S, which differed substantially on the individual items, and showed five cases of reinforcement, all in the predicted direction. Further, reinforcement was shown by an increase in both contingency and extinction sessions. Finally, the response of intermediate probability reinforced the response of least, but not the one of greatest, probability, indicating that a reinforcer cannot be identified absolutely, but only relative to the base response.

Animals↗
PubMed1964

REINFORCEMENT AND INSTRUCTIONS WITH MENTAL PATIENTS.

An attempt was made to modify a socially desirable response of mental patients. It was found that instructions to the patients had no enduring effect unless accompanied by reinforcement. Also, it was found that reinforcement was not effective unless the reinforcement procedure was accompanied by instructions that specified the basis for the reinforcement. Maximum change in behavior was obtained when the reinforcement procedure took advantage of the existing verbal repertoire of the patients. A significant methodological finding was that substantial modification of the behavior of psychotics could be achieved by briefly delaying, rather than withholding, food reinforcement.

Humans↗
PubMed1967

Effects of reinforcement scheduling on simultaneous discrimination performance.

Pigeons were trained on a discrete-trials, simultaneous discrimination procedure, with confusable stimuli such that asymptotic performance was about 85% correct. Trials were terminated if no response occurred within 2 sec of stimulus onset, so that probability of responding was free to vary. The schedule of reinforcement for correct responses was varied, with the following results: (1) there was no relation between frequency of reinforcement and accuracy of responding. (2) In extinction, the probability of responding fell to low levels, but accuracy remained roughly constant. (3) When reinforcement was available after a fixed number of trials or after a fixed number of correct responses, the probability of responding increased with successive trials after reinforcement, but accuracy was generally constant. (4) When every fifth correct response was reinforced, accuracy decreased immediately after reinforcement if the birds were required to respond on every trial.

Animals↗
PubMed1993

A parametric variation of delayed reinforcement in infants.

This study is an exploration of the parameters of delayed reinforcement with 6 infants (2 to 6 months old) in two experiments using single-subject repeated-reversal designs. In Experiment 1, unsignaled 3-s delayed reinforcement was used to increase infant vocalization rate when compared to a differential-reinforcement-of-other-than-vocalization condition and a yoked, no-contingency comparison condition. In Experiment 2, unsignaled 5-s delayed reinforcement was used to increase infant vocalization rate when compared to an alternating-treatments comparison condition. The alternating-treatments comparison consisted of 3-min components of differential reinforcement of other behavior and 3-min components of a nontreatment baseline. Successful conditioning was obtained in both experiments. These results contrast with those of previous infancy researchers who did not obtained conditioning with delays of 3 s and who attributed their findings to the limitations of the infant's memory capacity. We present an alternative conceptual framework and methodology for the analysis of delayed reinforcement in infants.

Behavior↗
PubMed1994

Human choice in concurrent ratio-interval schedules of reinforcement.

Seven undergraduates participated in a concurrent-choice experiment with monetary reinforcers. Response-independent analogues of variable-interval and variable-ratio schedules were used to assess whether subjects would maximize reinforcement rate. The optimal pattern of behavior, in terms of maximizing reinforcement rate, involved a large bias toward the ratio alternative, with only occasional sampling of the interval schedule. Most experiments with pigeons, however, demonstrate matching of response rates to reinforcement rates, with only slight biases for the ratio schedule. Although subjects in the present experiment allocated more time to the ratio alternative than required by matching, the magnitude of the bias did not approximate that predicted by a maximizing account. After exposure to clock stimuli correlated with the operation of each schedule, 1 subject's behavior did show a substantial level of bias, increasing the total number of reinforcers obtained, and lay at a point between the predictions of matching and maximizing. The other subjects, however, continued to respond less optimally. The present results can be accounted for by a view of matching that incorporates the effects of delayed reinforcement.

Choice Behavior↗
PubMed2000

Timeout postponement without increased reinforcement frequency.

Three experiments were conducted to examine pigeons' postponement of signaled extinction periods (timeouts) from a schedule of food reinforcement when such responding neither decreased overall timeout frequency nor increased the overall frequency of food reinforcement. A discrete-trial procedure was used in which a response during the first 5 s of a trial postponed an otherwise immediate 60-s timeout to a later part of that same trial but had no effect on whether the timeout occurred. During time-in periods, responses on a second key produced food according to a random-interval 20-s schedule. In Experiment 1, the response-timeout interval was 45 s under postponement conditions and 0 s under extinction conditions (responses were ineffective in postponing timeouts). The percentage of trials with a response was consistently high when the timeout-postponement contingency was in effect and decreased to low levels when it was discontinued under extinction conditions. In Experiment 2, the response-timeout interval was also 45 s but postponement responses increased the duration of the timeout, which varied from 60 s to 105 s across conditions. Postponement responding was maintained, generally at high levels, at all timeout durations, despite sometimes large decreases in the overall frequency of food reinforcement. In Experiment 3, timeout duration was held constant at 60 s while the response-timeout interval was varied systematically across conditions from 0 s to 45 s. Postponement responding was maintained under all conditions in which the response-timeout interval exceeded 0 s (the timeout interval in the absence of a response). In some conditions of Experiment 3, which were designed to control for the immediacy of food reinforcement and food-correlated (time-in) stimuli, responding postponed timeout but the timeout was delayed whether a response occurred or not. Responding was maintained for 2 of 3 subjects, suggesting that behavior was negatively reinforced by timeout postponement rather than positively reinforced by the more immediate presentation of food or food-correlated (time-in) stimuli.

Animals↗
PubMed2001

Response rate viewed as engagement bouts: effects of relative reinforcement and schedule type.

The rate of a reinforced response is conceptualized as a composite of engagement bouts (visits) and responding during visits. Part I of this paper describes a method for estimating the rate of visit initiations and the average number of responses per visit from log survivor plots: the proportion) of interresponse times (IRTs) longer than some elapsed time (log scale) plotted as a function of elapsed time. In Part 2 the method is applied to IRT distributions from rats that obtained food pellets by nose poking a lighted key under various multiple schedules of reinforcement. As expected, total response rate increased as a function of (a) increasing the rate of reinforcement (i.e., variable-interval [VI] 4 min vs. VI 1 mi), (b) increasing the amount of the reinforcer (one food pellet vs. four pellets), (c) increasing the percentage of reinforcers that were contingent on nose poking (25% vs. 100%), and (d) requiring additional responses after the end of the VI schedule (i.e., adding a tandem variable-ratio [VR] 9 requirement). The first three of these variables (relative reinforcement) increased the visit-initiation rate. The tandem VR, in contrast, increased the number of responses per visit. Thus, variables that have similar effects on total response rate can be differentiated based on their effects on the componemts of response rate.

Animals↗