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Results for “REINFORCEMENT”

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At least 127 records · Page 7Linked to original sources

PubMed1976

Relative reinforcer magnitude under a nonindependent concurrent schedule of cocaine reinforcement in rhesus monkeys.

Lever pressing by three rhesus monkeys was maintained under a two-lever concurrent schedule of cocaine reinforcement. Responding on one lever (constant-dose lever) produced a constant dose of 0.05 or 0.1 mg/kg/injection arranged according to a variable-interval 1-min schedule. Responding on the other lever (variable-dose lever) produced a comparison dose of cocaine (0.013 to 0.8 mg/kg/injection), also under a variable-interval 1-min schedule. The two variable-interval schedules were made nonindependent by arranging that the assignment of a reinforcer by one schedule inactivated the second schedule until the assigned reinforcer had been obtained. This modification ensured that the two cocaine doses were obtained with approximately equal frequency, regardless of the distribution of the subject's responding. Preference, indicated by relative response frequency on the variable-dose lever, was almost always for the larger of the doses and was a monotonic function of the comparison dose, except at the highest doses. Preferences at the highest comparison doses may have resulted from the low overall response rates exhibited at these doses. Relative response frequencies on the variable-dose lever roughly matched relative reinforcer magnitude (mg/kg/injection available on the variable-dose lever divided by the sum of mg/kg/injections available on each lever).

Animals↗

PubMedDate not supplied

Ethanol-reinforced responding and intake as a function of volume per reinforcement.

Number of ethanol reinforcements obtained and ethanol intake (mg/100 g body weight/hr) of 3 food-deprived rats were measured over a range of dipper volumes during daily 1 hr sessions. The rats had free access to water in their home cages between sessions. Ethanol concentration was 8 percent (W/V); each response was reinforced. As the volume per reinforcement increased, ethanol intake tended to increase while the number of reinforcements obtained decreased systematically. Responding was maintained by 8 percent (W/V) ethanol but not by water.

Alcohol Drinking↗

PubMed1993

Effects of caffeine and PD 116,600 on the differential-reinforcement-of-low rate 72-S (DRL 72-S) schedule of reinforcement.

Caffeine and PD 116,600 were found to decrease the reinforcement rate and increase the response rate in rats performing under a differential-reinforcement-of-low rate 72-s (DRL 72-s) schedule of reinforcement. In contrast, antidepressant drugs previously have been found to increase the reinforcement and decrease the response rate. Caffeine has been found to test similar to antidepressant drugs on at least one other behavioral screen, but caffeine does not possess clinical antidepressant properties. These results provide further support for the DRL 72-s schedule as a behavioral screen for antidepressant drugs.

Animals↗

PubMedDate not supplied

Functional analysis of aberrant behavior maintained by automatic reinforcement: assessments of specific sensory reinforcers.

The purpose of this study was to develop a systematic functional assessment package for aberrant behaviors maintained by nonsocial (automatic) reinforcement. The assessment package included four components: (1) functional analysis, (2) antecedent assessment of specific automatic reinforcement sources, (3) stimulus preference assessment, and (4) treatment evaluation. Functional analysis data indicated automatic reinforcement functions of the stereotypy exhibited by a 10-year-old male and the self-injury (SIB) exhibited by a 30-year-old male. Antecedent assessments of sensory classes indicated that auditory stimulation and tactile stimulation were associated with stereotypy and SIB, respectively. A multiple-stimulus-without-replacement procedure was conducted with each participant to identify the most- and least-preferred stimuli within the identified sensory classes. In an attempt to validate the assessment package for each participant, a DRO procedure was implemented using a reversal design with a multielement component. DRO procedures using stimuli within the targeted sensory classes were successful in eliminating the aberrant behaviors of both participants. The results are discussed in the context of improving the methodology for assessing and treating automatically reinforced behaviors.

Adult↗

PubMed1996

Reinforced variability decreases with approach to reinforcers.

Anticipation of rewards had different effects on operant variability than on operant repetition. We reinforced variable (VAR) response sequences in groups of rats and pigeons and repetitive (REP) response sequences in separate groups. A fixed number of variations or repetitions was required per food reinforcer (e.g., fixed-ratio 4). Although VAR contingencies resulted in high levels of variability and REP contingencies in high repetition, opposite patterns of performance accuracy were observed as rewards were approached. Likelihood of satisfying REP contingencies increased within the fixed ratio, whereas likelihood of satisfying VAR contingencies decreased. These opposite patterns of accuracy were also generated by conditioned reinforcing stimuli correlated with food. Constraints on variability by proximity to reinforcers may explain some detrimental effects of reward.

Animals↗

PubMed2000

Effects of noncontingent reinforcement on problem behavior and stimulus engagement: the role of satiation, extinction, and alternative reinforcement.

This study examined the effects of noncontingent reinforcement (NCR) with and without extinction on problem behavior and stimulus engagement (consumption of reinforcement) of 4 participants. Reductions in problem behavior using NCR have frequently been attributed to both satiation of the reinforcer and extinction. In the current study, aspects of the NCR treatment effects were difficult to explain based solely on either a satiation or an extinction account. Specifically, it was found that stimulus engagement remained high throughout the NCR treatment analysis, and that problem behavior was reduced to near-zero levels during NCR without extinction. The implications of these findings are discussed with respect to the satiation and extinction hypotheses frequently described in the applied literature. Findings from basic studies examining the effects of response-independent schedules are presented, and are used as the basis for a matching theory account of NCR-related effects. It is proposed that reductions in problem behavior observed during NCR interventions may be a function of the availability of alternative sources of reinforcement.

Child↗

PubMed2003

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.

Adult↗

PubMed2004

An alternative method of thinning reinforcer delivery during differential reinforcement.

Differential reinforcement of alternative behavior (DRA) may result in rates of reinforcement that are impractical for caregivers to implement; therefore, recent research has examined methods for thinning reinforcer delivery during DRA. In this study, reinforcer delivery was thinned during DRA by restricting access to the participant's alternative response materials.

Aggression↗

PubMed2004

Obtained versus programmed reinforcement practical considerations in the treatment of escape-reinforced aggression.

This investigation provides a preliminary examination of the difference between programmed and obtained reinforcement rates and its potential influence during treatment of aggression in a natural setting. Following a functional analysis that suggested that the aggression of a boy with autism was negatively reinforced, intervention was implemented by the boy's mother. Concurrent fixed-ratio (FR) 1 FR 1 schedules of escape were arranged for manding and aggression. When mands failed to compete effectively with aggression, obtained reinforcement ratios were calculated; these indicated that obtained reinforcement varied from the programmed schedule for aggression but not for mands. Increasing the rate of prompts for mands resulted in an increase in mands and a decrease in aggression to near-zero levels.

Aggression↗

PubMed1991

Cocaine and food as reinforcers: effects of reinforcer magnitude and response requirement under second-order fixed-ratio and progressive-ratio schedules.

Reinforcer magnitude and fixed-ratio requirement were varied under two second-order schedules. Under one, the first sequence of a fixed number of responses completed after the lapse of a 10-min fixed interval produced reinforcement. Under the second, a second-order progressive-ratio schedule, the fixed number of responses increased after each reinforcement. Either cocaine (0 to 300 micrograms/kg/inj) or food (0 to 5,700 mg/delivery) reinforcers were delivered. Under some conditions, a 2-s illumination of stimulus lights occurred on completion of each ratio sequence. Under the second-order schedule, as cocaine dose or amount of food increased, rates of responding increased; at the highest values, rates of responding decreased. Increases in the ratio requirement from 10 to 170 responses minimally decreased overall response rates. Under the second-order progressive-ratio schedule, increases in dose of cocaine or amount of food increased rates of responding; at the highest amounts of food, rates of responding decreased but response rates at the highest dose of cocaine remained relatively high. The highest ratio requirement that was completed (breaking point) depended on the dose of cocaine but was less dependent on the amount of food. Removing brief-stimulus presentations had a greater effect on completion of ratio requirements with cocaine compared to food.

Animals↗

PubMed2005

Discriminative stimuli that follow the absence of reinforcement are preferred by pigeons over those that follow reinforcement.

Clement, Feltus, Kaiser, and Zentall (2000) found that when pigeons have to work to obtain a discriminative stimulus that is followed by reinforcement, they prefer a discriminative stimulus that requires greater effort over one that requires less effort. The authors suggested that such a preference results from the greater change in hedonic value that occurs between the more aversive event and the onset of the stimulus that signals reinforcement, a contrast effect. It was hypothesized that any stimulus that follows a relatively more aversive event would be preferred over a stimulus that follows a relatively less aversive event. In the present experiment, the authors tested the counterintuitive prediction of that theory, that pigeons should prefer a discriminative stimulus that follows the absence of reinforcement over a discriminative stimulus that follows reinforcement. Results supported the theory.

Animals↗

PubMed2002

[Modes of reinforcement and gender and culture of experimenter and subject: effects of "alien" and external reinforcement for Japanese and American men and women].

In this study, we examined external and "alien" reinforcement (ER and AR. respectively) as a factor in social learning, and studied the combined effects of culture and reinforcement mode. A female (Experiment 1) and a male (Experiment 2) experimenters conducted experimental sessions. Both men and women, who grew up in the same culture as the experimenter, participated and performed the experimental task. A three-way interaction effect of experimenter gender, culture, and reinforcement mode was found on task performance. And the effect was more pronounced for a Japanese experimenter. A female and a male experimenters conducted Experiments 3 and 4, respectively; however participants this time were men and women who grew up in different cultures than the experimenter. Results indicated that the pattern of the subject gender and reinforcement mode interaction effect, when the experimenter was Japanese with American subjects, was exactly opposite to that when the experimenter was American. These experiments showed that AR was as effective for social learning as ER, and that the cultural backgrounds of experimenter and subject influenced AR and ER effectiveness.

Adult↗

PubMed2001

The influence of fibre placement and position on the efficiency of reinforcement of fibre reinforced composite bridgework.

The effect of placement of ultra-high molecular weight polyethylene (UHMWPE) fibres on the flexural properties and fracture resistance of a direct dental composite was investigated. The UHMWPE fibres are increasingly being used for the reinforcement of laboratory fabricated resin composite crown and bridgework. The aim of this study was to assess the effect of a commonly used laboratory fabrication variable on the in vitro strength of beam shaped specimen simulating a three-unit fixed bridge. Four groups (10 specimens per group) of Herculite XRV were prepared for flexural modulus and strength testing after reinforcement with UHMWPE fibres. Two groups of control specimens were prepared without any fibre reinforcement. Half the specimen groups were stored in distilled water and the other groups were stored dry, both at 37 degrees C for 2 weeks before testing. The results of this study showed that placement of fibre at or slightly away from the tensile side improved the flexural properties of the composite in comparison with the unreinforced control specimen groups whilst the mode of failure differed according to fibre position. Scanning electron microscope (SEM) investigation revealed that placement of the fibre slightly away from the tensile side favoured crack development and propagation within the resin bridging the interfibre spaces in addition to debonding parallel to the direction of fibre placement. Laboratory fabrication variables may effect the strength of fibre reinforced bridgework significantly.

Analysis of Variance↗

PubMed2002

Strain measurement in a concrete beam by use of the Brillouin-scattering-based distributed fiber sensor with single-mode fibers embedded in glass fiber reinforced polymer rods and bonded to steel reinforcing bars.

The strain measurement of a 1.65-m reinforced concrete beam by use of a distributed fiber strain sensor with a 50-cm spatial resolution and 5-cm readout resolution is reported. The strain-measurement accuracy is +/-15 microepsilon (microm/m) according to the system calibration in the laboratory environment with non-uniform-distributed strain and +/-5 microepsilon with uniform strain distribution. The strain distribution has been measured for one-point and two-point loading patterns for optical fibers embedded in pultruded glass fiber reinforced polymer (GFRP) rods and those bonded to steel reinforcing bars. In the one-point loading case, the strain deviations are +/-7 and +/-15 microepsilon for fibers embedded in the GFRP rods and fibers bonded to steel reinforcing bars, respectively, whereas the strain deviation is +/-20 microepsilon for the two-point loading case.

Journal Article↗

PubMed1969

Delayed reinforcement versus reinforcement after a fixed interval.

When interreinforcement intervals were equated, pigeons demonstrated little or no preference between reinforcement after a delay interval and reinforcement presented on a fixed-interval schedule. The small preferences sometimes found for the fixed interval (a) were considerably smaller than when the delay and fixed intervals differed in duration, and (b) were caused by the absence of light during the delay. These results suggest that the effects of delayed reinforcement on prior responding can be reproduced by imposing a temporally equal fixed-interval schedule in place of the delay; and, therefore, that the time between a response and reinforcement controls the probability of that response, whether other responses intervene or not.

Journal Article↗

PubMed1969

Effects of instructions and reinforcement-feedback on human operant behavior maintained by fixed-interval reinforcement.

In three experiments, human subjects were trained on a five-component multiple schedule with different fixed intervals of monetary reinforcement scheduled in the different components. Subjects uninstructed about the fixed-interval schedules manifested high and generally equivalent rates regardless of the particular component. By comparison, subjects given instructions about the schedules showed orderly progressions of rates and temporal patterning as a function of the interreinforcement intervals, particularly when feedback about reinforcement was delivered but also when reinforcement-feedback was withheld. Administration of the instructions-reinforcement combination to subjects who had already developed poorly differentiated behavior, however, did not make their behavior substantially better differentiated. When cost was imposed for responding, both instructed and uninstructed subjects showed low and differentiated rates regardless of their prior histories. It was concluded that instructions can have major influences on the establishment and maintenance of human operant behavior.

Journal Article↗

PubMed1971

Reinforcement schedules: the role of responses preceding the one that produces the reinforcer.

In a two-key pigeon chamber, variable-interval reinforcement was scheduled for a specified number of pecks, emitted either on a single key or in a particular sequence on the two keys. Although the distribution of pecks between the two keys was affected by whether pecks were required on one or on both keys, the total pecks emitted was not; the change from a one-key to a two-key requirement simply moved some pecks from one key to the other. Thus, each peck preceding the one that produced the reinforcer contributed independently to the subsequent rate of responding; the contribution of a particular peck in the sequence was determined by the time between its emission and the delivery of the reinforcer (delay of reinforcement), and was identified by the proportion of pecks moved from one key to the other when the response requirement at that point in the sequence was moved from one key to the other.

Journal Article↗

PubMed1979

Reinforcement magnitude and the inhibiting effect of reinforcement.

In a two-key concurrent variable-interval schedule (using pigeons), if the reinforcement frequency for one response is held constant while that for the other is increased, the rate of response on the constant key decreases. The immediate reinforcement for key pecking can usually be conceptualized as the change from a condition in which the key light is on and the food hopper light is off to one in which the key light is off and the hopper light is on. The prechange condition is associated with a delay to food of one-half the average interreinforcement interval in effect during this condition. The postchange condition is associated with a delay to food of about .5 seconds. The programming of additional reinforcement results in a decrease in the delay to food associated with the prechange stimulus condition, and thus a decrease in the value of the improvement that results from the change. This would appear to be analogous to a decrease in the amount of reinforcement, and thus sufficient explanation for the decrease in the rate of the response.

Journal Article↗