Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Reinforcement Schedule”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1968

Maintenance of responding under a fixed-interval schedule of electric shock-presentation.

Squirrel monkeys trained to respond under a schedule in which each response postponed the delivery of electric shock developed a steady rate of responding. When a schedule in which an electric shock was presented following the first response occurring after 10 minutes (10-minute fixed-interval schedule) was programed concurrently, there was little effect on the pattern of responding. When the shock-postponement schedule was eliminated, the fixed-interval schedule of shock-presentation maintained a pattern of positively accelerated responding that is characteristic of fixed-interval schedules of reinforcement.

Animals↗
PubMed1982

Choice and behavioral patterning.

Ten pigeons pecked left and right keys in a discrete-trials experiment in which access to food was contingent upon changeovers to the right key after particular runs of left-key pecks. In each of three sets of conditions, two run lengths were reinforced according to a concurrent variable-interval schedule: reinforcement followed runs of either 1 or 2, 1 or 4, or 2 or 4 left-key pecks preceding changeovers. The intertrial interval separating successive pecks was varied from .5 to 10.0 sec, and the relative frequency of reinforcement for the shorter of the two reinforced runs was varied from 0 to .75. The contingencies established local behavioral patterning that roughly approximated that required for reinforcement. For a fixed pair of reinforced run lengths, preference for the shorter of the two frequently increased as the intertrial interval increased and therefore as the minimum temporal durations of both reinforced runs increased. Preference for the shorter of the two also increased as its corresponding relative frequency of reinforcement increased. Both of these effects on preference were qualitatively similar to corresponding effects in previous research with two different kinds of reinforced behavioral patterns, interresponse times and interchangeover times. In all these experiments, analytical units were found in the temporal patterns of behavior, not in the behavior immediately contiguous with a reinforcer. It is suggested that a particular local temporal pattern of behavior is established to the extent to which it is repeatedly remembered when reinforcers are delivered, regardless of whether the delivery of a reinforcer is explicitly contingent upon that pattern.

Journal Article↗
PubMed1992

Inverse relations between preference and contrast.

Pigeons were trained on a multiple schedule in which two target components with identical reinforcement schedules were followed by either the same-valued schedule or by extinction. Response rate increased in both target components but was higher in the target component followed by extinction, replicating previous findings of positive anticipatory contrast. A similar design was used to study negative contrast, in that the two target components were followed either by the same-valued schedule or by a higher valued schedule. Negative contrast occurred equally, on average, in both target components, thus failing to demonstrate negative contrast that is specifically anticipatory in nature. When the stimuli correlated with the two target components were paired in choice tests, the pattern of preference was in the opposite direction. For the positive contrast procedure, no significant preference between the two target stimuli was evident. But for the negative contrast procedure, preference favored the stimulus followed by the higher valued schedule. The results demonstrate a functional dissociation between positive and negative contrast in relation to stimulus value. More generally, the results demonstrate an inverse relation between response rate and preference and challenge existing accounts of contrast in terms of the concept of relative value.

Journal Article↗
PubMed2006

Behavioral determinants of drug action. The contributions of Peter B. Dews.

Peter B. Dews played a significant role in shaping the distinctive characteristics and defining the underlying principles of the discipline of behavioral pharmacology. His early and sophisticated use of schedules of reinforcement in the 1950s, incorporated from research in the experimental analysis of behavior and integrated into the discipline of pharmacology, provided tremendous insight, inspiration, and impetus to the newly emerging field of behavioral pharmacology. The experimental findings generated by Dews' research, blending the sophisticated use of behavior and pharmacological principles together with the elegant manner of their presentation and far-reaching implications, provided the force and momentum to establish and direct behavioral pharmacology for several decades. This article attempts to capture some of Dews' research that integrated and inspired the blending of sophisticated behavioral work with that of pharmacology.

Animals↗
PubMed2002

Effects of REM sleep deprivation on a multiple schedule of appetitive reinforcement.

The effects of rapid eye movement sleep deprivation (REMSD) on appetitively reinforced responding by rats was studied in two experiments. In Experiment 1, a lever press was maintained on a baseline multiple FR 30 FI 60-s schedule of reinforcement that was reestablished after each experimental manipulation. Animals were then repeatedly exposed to 24, 48, or 96 h of REMSD and equivalent periods of tank control and cage control conditions. For all animals responding was reduced only after 96 h of REMSD, but tolerance to REMSD developed following repeated exposures. Experiment 2, replicated the procedures of Experiment 1 except that the apparatus was modified to prevent ad libitum access to REMSD during operant sessions. Animals were repeatedly exposed to 96 h of REMSD and equivalent periods of tank control and cage control conditions. No reduction in responding was observed in Experiment 2. The current findings, in conjunction with previous research, suggest that REMSD may have qualitatively different effects on responding maintained by positive versus negative reinforcement.

Animals↗
PubMed1986

An inhalational behavioral chamber.

An inhalational (flow-through) behavioral chamber has been designed and prepared in order to facilitate recording of the behavioral performance of a small experimental animal (e.g., rat and mouse) while the subject is being exposed to an inhalant (vapor or gas). The animal can be clearly viewed during behavioral performance inside the chamber, which consists of a cylindrical glass jar. The apparatus is made up of easily available materials (e.g., glass, metal, Teflon, etc.) that are not affected by usual industrial solvents. At the present stage of its development, three types of behavioral schedules can be performed within the chamber: schedules involving brain stimulation (e.g., self-stimulation, avoidance of aversive stimulations); liquid-reinforced schedules (e.g., fixed ratio, fixed interval, variable ratio, variable interval, differential reinforcement of low rates); shock avoidance (classical or continuous). The schedules can be microcomputer assisted. The device is suitable for study of behavioral pharmacology and toxicology of inhalants.

Animals↗
PubMed1994

Shaping in the 21st century: Moving percentile schedules into applied settings.

The present paper provides a primer on percentile reinforcement schedules, which have been used for two decades to study response differentiation and shaping in the laboratory. Arranged in applied settings, percentile procedures could be used to specify response criteria, standardizing treatment across subjects, trainers, and times to provide a more consistent training environment while maintaining the sensitivity to the individual's repertoire that is the hallmark of shaping. Percentile schedules are also valuable tools in analyzing the variables of which responding is a function, both inside and outside the laboratory. Finally, by formalizing the rules of shaping, percentile schedules provide a useful heuristic of the processes involved in shaping behavior, even for those situations that may not easily permit their implementation. As such, they may help further sensitize trainers and researchers alike to variables of critical importance in behavior change.

Journal Article↗
PubMed1972

Concurrent performances: rate and accuracy of free-operant oddity responding.

In pigeon's oddity performances, maintained by variable-interval reinforcement of pecks on the odd key of three keys in a triangular array, accuracy and response rate varied inversely with the rate of variable-interval reinforcement scheduled concurrently for pecks on a fourth, spatially isolated key. But when variable-interval and extinction components alternated in a multiple schedule for pecks on the spatially isolated key, oddity accuracy was greater during variable-interval components than during extinction components. Oddity response rate was not affected systematically by the alternating components. Changeovers between the oddity keys and the spatially isolated key were frequent during variable-interval components; responding occurred almost exclusively on the oddity keys during extinction components. This difference in performance during the two components was eliminated by arranging stimulus-correlated variable-interval reinforcement in the multiple schedule on the spatially isolated key: a stimulus was presented in the variable-interval components only when reinforcement became available, thereby reducing responding on this key to near-zero levels in both components while maintaining the variable-interval reinforcement. The effect of the multiple-schedule components on oddity accuracy was not altered, however, and thus apparently depended directly on concurrent reinforcement and not on differential sequential properties of concurrent responding during the two components.

Journal Article↗
PubMed1971

Percentage reinforcement of fixed-ratio and variable-interval performances.

Twenty to seventy per cent of the reinforcements scheduled for pigeons' fixed-ratio 80 performances were replaced by a 4-sec timeout. Pauses after reinforced ratios were unchanged at 80% reinforcement, but were lengthened at lower reinforcement percentages. Pauses after nonreinforced ratios were shorter than post-reinforcement pauses. When 50% of the reinforcements arranged by a variable-interval 60-sec schedule were replaced by a 4-sec timeout, pauses after reinforcement omission increased. Both frustrative nonreward and reinforcement aftereffects notions can explain the fixed-ratio results; neither easily explains the variable-interval data.

Journal Article↗
PubMed1995

Rate-dependency hypothesis and the rate-decreasing effects of d-amphetamine on schedule-induced drinking.

The high levels of drinking induced by intermittent food-reinforcement schedules are dose-dependently reduced by acute doses of d-amphetamine. The present study evaluated whether the effects of d-amphetamine on this schedule-induced drinking reflect the reduction of high rates of responding. Twenty-four rats were divided into six groups (n = 4) according to the interval and time durations of a multiple fixed-time (FT) fixed-interval (FI) schedule (15s, 30s, 60s, 120s, 240s and 480s). FT components were signalled by a tone and by lever withdrawal. Doses of 0.25 to 4.0mg/kg of d-amphetamine were administered i.p. 10min before test sessions. d-amphetamine produced similar dose-dependent reductions in rate of licking induced by FT and FI schedules. Rate-decreasing effects on operant lever pressing were also found after administrations of d-amphetamine. The dose-dependent decrements produced by d-amphetamine were a function of the inter-food interval length in both schedule-induced and operant behaviours. These rate-decreasing effects were rate-dependent, but d-amphetamine interacted differentially with control rates of adjunctive and operant behaviours, causing a greater suppression of the lower rates of adjunctive licking and the higher rates of operant lever pressing.

Journal Article↗
PubMed2001

Assessing reinforcers under progressive schedule requirements.

Recent research findings suggest that reinforcing stimuli may be differentially effective as response requirements increase. We extended this line of research by evaluating responding under increasing schedule requirements via progressive-ratio schedules and behavioral economic analyses. The differential effectiveness of preferred stimuli in treating destructive behavior maintained by automatic reinforcement also was examined. Results showed that one of two stimuli was associated with more responding under increasing schedule requirements for the 4 participants. Furthermore, stimuli associated with more responding under increasing schedule requirements generally were more effective in treating destructive behavior than stimuli associated with less responding. These data suggest that progressive-ratio schedules and behavioral economic analyses may be useful for developing a new technology for reinforcer identification. From a clinical perspective, these results suggest that two reinforcers may be similarly effective for low-effort tasks and differentially effective for high-effort tasks.

Adolescent↗
PubMed2006

Effect of signaling reinforcement on resistance to change in a multiple schedule.

This study evaluated the effect of a signal on resistance to change using a multiple schedule of reinforcement. Experiment 1 presented pigeons with three schedules: a signaled delay to reinforcement schedule (a two-link chain schedule with a variable-interval 120-s initial link followed by a 5-s fixed-time schedule), an unsignaled delay schedule (a comparable two-link tandem schedule), and an immediate, zero-delay variable-interval 125-s schedule. Two separate disruption procedures assessed resistance to change: extinction and adding a variable-time 20-s schedule of reinforcement to the inter-component interval. Resistance to change tests were conducted twice, once with the signal stimulus (the terminal link of the chain schedule) present and once with it absent. Results from both disruption procedures showed that signal absence reduced resistance to change for the pre-signal stimulus. In probe choice tests subjects strongly preferred the signal stimulus over the unsignaled stimulus and exhibited no reliable preference when given a choice between the signal stimulus and immediate stimulus. Experiment 2 presented two equal signaled schedules where, during resistance to change tests, the signal remained for one schedule and was removed for the second. Resistance to change was consistently lower when the signal was absent.

Animals↗
PubMed1978

Performance of rats under concurrent variable-interval schedules of negative reinforcement.

The behavior of rats under concurrent variable-interval schedules of negative reinforcement was examined. A single one-minute variable-interval programmer determined the availability of 30-second timeouts from electric shock. These were assigned to one or the other of the two component schedules with a probability of 0 to 1.0. The response requirement for the component schedules was standing to the right or left of the center of the experimental chamber. With a six-second changeover delay, the relative time spent under one component schedule varied directly and linearly with the relative number of timeouts earned under that component schedule. The absolute number of changeovers was highest when a similar number of timeouts was earned under each component schedule, and lowest when all or nearly all timeouts were earned under one component schedule. In general, these relations are similar to those reported with concurrent variable-interval schedules of positive reinforcement.

Journal Article↗
PubMed2005

The effect of orbital prefrontal cortex lesions on performance on a progressive ratio schedule: implications for models of inter-temporal choice.

In a previous experiment [Kheramin S, Body S, Mobini S, Ho M-Y, Velazquez-Martinez DN, Bradshaw CM, et al. Effects of quinolinic acid-induced lesions of the orbital prefrontal cortex on inter-temporal choice: a quantitative analysis. Psychopharmacology 2002;165: 9-17], destruction of the orbital prefrontal cortex (OPFC) in rats altered choice between two delayed food reinforcers, enhancing preference for the larger reinforcer. Theoretical analysis based on a quantitative model of inter-temporal choice [Ho M-Y, Mobini S, Chiang T-J, Bradshaw CM, Szabadi E. Theory and method in the quantitative analysis of 'impulsive choice' behaviour: implications for psychopharmacology. Psychopharmacology 1999;146:362-72] indicated that the lesion had increased the relative value of the larger of the two reinforcers due to a general reduction of absolute reinforcer value. The present experiment tested this hypothesis using a reinforcement schedule that did not entail either explicit choice or delayed reinforcement. Ten rats received quinolinic acid-induced lesions of the OPFC, and ten rats received sham lesions. The rats were trained under a progressive-ratio schedule of food reinforcement for 60 daily sessions. Response rates in successive ratios were a bitonic (inverted-U) function of ratio size. Analysis of the data using a three-parameter equation derived from a quantitative model of ratio schedule performance [Killeen PR. Mathematical principles of reinforcement. Behav. Brain Sci. 1994;17:105-72] revealed that the parameter specifying hypothetical reinforcer value was significantly lower in the OPFC-lesioned group than in the sham-lesioned group, consistent with the hypothesis that destruction of the OPFC resulted in devaluation of the food reinforcer.

Animals↗
PubMedDate not supplied

Effects of prenatal maternal ethanol on male offspring progressive-ratio performance and response to amphetamine.

This study was designed to further explore the nature of our previously reported reduction in the efficacy of food reinforces for prenatal ethanol-exposed mice. We determined the effect of prenatal ethanol exposure on responding for food delivered on a progressive-ratio (PR) reinforcement schedule, which has been shown to be sensitive to changes in motivation and/or value of reinforcers, and we assessed the effects of amphetamine on responding maintained by the PR schedule. Subjects were adult (12 months old) male offspring of C57BL/6J mice fed liquid diets containing either ethanol (25% ethanol-derived calories, N = 12) or sucrose (25% sucrose-derived calories, N = 9) during gestation days 5-17. Prenatal ethanol-exposed mice differed from controls by having lower response rates and a greater disruption of responding following amphetamine injections. The reduced responding for food reward on the PR schedule supports our previously advanced hypothesis that prenatal ethanol reduces the efficacy of food reinforcers. The enhanced effects of amphetamine found in these adult mice is in agreement with previous reports on young rats. Although either of the effects of prenatal ethanol exposure observed in the present study are suggestive of altered DA systems, current neurochemical studies on either rats or mice provide no support for the hypothesis.

Amphetamine↗
PubMed2005

Microinjections of SCH 23390 in the ventral tegmental area reduce operant responding under a progressive ratio schedule of food reinforcement in rats.

We recently demonstrated that dopamine D1 receptors in the ventral tegmental area (VTA) are involved in intravenous cocaine reward. Here, we investigated whether VTA D1 receptors also are involved in food reward by testing the hypothesis that blockade of dopamine D1 receptors in the VTA attenuates the rewarding effects of food. Eighteen rats, with bilateral cannulae positioned to allow for microinjections in or just dorsal to the VTA, were trained to lever press under a progressive ratio schedule of reinforcement. After stable break points (BPs) were established, the rats received bilateral microinjections of SCH 23390, a D1 receptor antagonist. In Experiment 1, where the reward consisted of 1 food pellet, injections of SCH 23390 (0, 1, 2, or 4 microg/0.5 microl) in the VTA (N=9) significantly decreased BPs (P <0.001), while bilateral microinjections dorsal to the VTA (N=9) did not. In Experiment 2 (N=6), where the reward consisted of 1 or 2 food pellets, intra-VTA injections of SCH 23390 (0 and 4 microg/0.5 microl) decreased BPs at the 1 food pellet level (P <0.05), but not at the 2 food pellet level. Thus, the data showed that intra-VTA microinjections of SCH 23390 reduced the rewarding effects of food. This effect was surmountable by increasing food reward, ruling out motoric effects, and did not occur when injections were made dorsal to VTA, eliminating the possibility that the effect was caused by the dorsal diffusion of drug. These data suggest that dendritically released dopamine in the VTA plays a significant role in food reward.

Animals↗
PubMed1999

Effects of contingent and non-contingent cocaine on drug-seeking behavior measured using a second-order schedule of cocaine reinforcement in rats.

Rats were trained to respond with intravenous cocaine as the reinforcer under a fixed interval 15-min schedule, during which conditioned stimuli paired with cocaine were presented contingent on completion of a fixed ratio of 10 responses (i.e., second-order schedule of reinforcement). The effects of contingent and noncontingent cocaine were investigated. The results show that pretreatment with noncontingent (i.e., experimenter-administered) cocaine led to a satiation-like effect that was reflected in decreased numbers of responses and a tendency for an increased latency to initiate responding when the doses of cocaine administered were similar to or higher than the training/maintenance dose of cocaine. By contrast, noncontingent administration of cocaine doses lower than the training/maintenance dose, and response-contingent cocaine administration, led to increased drug-seeking behavior, as reflected in increased numbers of responses. The present data indicate that at least two factors determine whether administration of cocaine would lead to drug-seeking behavior: whether the cocaine administration is contingent or noncontingent, and the relative magnitude of the cocaine dose administered in relation to the training/maintenance dose of cocaine.

Analysis of Variance↗