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PubMed1990

Effects of ethanol on reinforced variations and repetitions by rats under a multiple schedule.

Response sequences emitted by five Long-Evans rats were reinforced under a two-component multiple schedule. In the REPEAT component, food pellets were contingent upon completion of a left-left-right-right (LLRR) sequence on two levers. In the VARY component, pellets were contingent upon variable sequences (i.e., a sequence was reinforced only if it differed from each of the previous five sequences). The rats learned to emit LLRR sequences in the REPEAT component and variable sequences in VARY. Intraperitoneal injections of ethanol (1.25, 1.75, and 2.25 g/kg) significantly increased sequence variability in REPEAT, thereby lowering reinforcement probability, but had little effect on sequence variability in the VARY component. These results extend previous findings that alcohol impairs the performance of reinforced repetitions but not of reinforced variations in response sequences.

Animals↗
PubMed1991

The interaction between stimulus and reinforcer control on remembering.

In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering.

Animals↗
PubMed1991

Effects of varying stimulus disparity and the reinforcer ratio in concurrent-schedule and signal-detection procedures.

The present study measured the effects of stimulus and reinforcer variations on pigeons' behavior in two different choice procedures. Two intensities of white light were presented as the stimuli on the main key in a switching-key concurrent schedule and as the sample stimuli in a signal-detection procedure. Under both procedures, the scheduled rate of reinforcement was varied across conditions to produce various ratios of obtained reinforcement. These ratios were obtained for seven pairs of light intensities. In the concurrent schedules, the effects of reinforcer-ratio variations were positively correlated with the physical disparity between the two light intensities. In the signal-detection procedure, changes in the reinforcer ratio produced greater effects on performance when stimulus disparity was very low or very high compared to those found at intermediate levels of stimulus disparity. This discrepancy creates a dilemma for existing behavioral models of signal-detection performance.

Animals↗
PubMed1993

A selectionist approach to reinforcement.

We describe a principle of reinforcement that draws upon experimental analyses of both behavior and the neurosciences. Some of the implications of this principle for the interpretation of behavior are explored using computer simulations of adaptive neural networks. The simulations indicate that a single reinforcement principle, implemented in a biologically plausible neural network, is competent to produce as its cumulative product networks that can mediate a substantial number of the phenomena generated by respondent and operant contingencies. These include acquisition, extinction, reacquisition, conditioned reinforcement, and stimulus-control phenomena such as blocking and stimulus discrimination. The characteristics of the environment-behavior relations selected by the action of reinforcement on the connectivity of the network are consistent with behavior-analytic formulations: Operants are not elicited but, instead, the network permits them to be guided by the environment. Moreover, the guidance of behavior is context dependent, with the pathways activated by a stimulus determined in part by what other stimuli are acting on the network at that moment. In keeping with a selectionist approach to complexity, the cumulative effects of relatively simple reinforcement processes give promise of simulating the complex behavior of living organisms when acting upon adaptive neural networks.

Behavior↗
PubMed1994

In vitro reinforcement of hippocampal bursting: a search for Skinner's atoms of behavior.

A novel "in vitro reinforcement" paradigm was used to investigate Skinner's (1953) hypotheses (a) that operant behavior is made up of infinitesimal "response elements" or "behavioral atoms" and (b) that these very small units, and not whole responses, are the functional units of reinforcement. Our tests are based on the assumption that behavioral atoms may plausibly be represented at the neural level by individual cellular responses. As a first approach, we attempted to reinforce the bursting responses of hippocampal units in a highly reduced brain-slice preparation with local micropressure applications of behaviorally reinforcing dopaminergic drugs. The same injections were administered independently of bursting to provide a "noncontingent" control for nonspecific stimulation or facilitation of firing. It was found that the bursting responses of individual CA1 pyramidal neurons may be progressively facilitated in a dose-related manner by response-contingent (but not noncontingent) injections of dopamine itself, the dopamine D1-preferring agonist SKF 82958, the D3-preferring agonist quinpirole, and the D2-like selective agonist (+)-4-propyl-9 hydroxynapthoxazine. These findings support the conclusion that unit bursting responses can be reinforced in vitro in hippocampal slices, and they further suggest that the same dopamine receptor subtypes are involved in both cellular and behavioral operant conditioning. The results thus provide indirect support for Skinner's atoms-of-behavior hypothesis.

Animals↗
PubMed1997

Body weight and response acquisition with delayed reinforcement.

The relation between body weight and responding established with unsignaled delayed reinforcement was investigated. In three experiments, naive rats were deprived to either 70%, 80%, or 90% of ad libitum weight and were then exposed to tandem variable-interval 15-s differential-reinforcement-of-other-behavior 30-s schedules. The tandem schedule defined a resetting unsignaled delay-of-reinforcement procedure. In the first experiment, speed of magazine training, acquisition of lever pressing, and final rate of lever pressing were related to body weight. In the next experiment, lever pressing was established and maintained in rats that were magazine trained at 70% of ad libitum weight but that were then exposed to the delay procedure at 90% of ad libitum weight. Responding did not change consistently either across or within subjects in subsequent conditions in which body weight was manipulated. In the final experiment, lever pressing was established and maintained with delayed reinforcement in the absence of magazine training for each of 2 rats at 70% and for 1 of 2 rats at 90% of ad libitum weight. The results further illuminate the conditions under which responding can be established in the absence of training and when such responses are reinforced only following an unsignaled delay period.

Animals↗
PubMed2003

Rats' performance on variable-interval schedules with a linear feedback loop between response rate and reinforcement rate.

Three experiments investigated whether rats are sensitive to the molar properties of a variable-interval (VI) schedule with a positive relation between response rate and reinforcement rate (i.e., a VI+ schedule). In Experiment 1, rats responded faster on a variable ratio (VR) schedule than on a VI+ schedule with an equivalent feedback function. Reinforced interresponse times (IRTs) were shorter on the VR as compared to the VI+ schedule. In Experiments 2 and 3, there was no systematic difference in response rates maintained by a VI+ schedule and a VI schedule yoked in terms of reinforcement rate. This was found both when the yoking procedure was between-subject (Experiment 2) and within-subject (Experiment 3). Mean reinforced IRTs were similar on both the VI+ and yoked VI schedules, but these values were more variable on the VI+ schedule. These results provided no evidence that rats are sensitive to the feedback function relating response rate to reinforcement rate on a VI+ schedule.

Animals↗
PubMed2004

Bouts of responding: the relation between bout rate and the rate of variable-interval reinforcement.

By nose poking a lighted key, rats obtained food pellets on either a variable-interval schedule of reinforcement or a schedule that required an average of four additional responses after the end of tile variable-interval component (a tandem variable-interval variable-ratio 4 schedule). With both schedule types, the mean variable interval was varied between blocks of sessions from 16 min to 0.25 min. Total rate of key poking increased similarly as a function of the reinforcer rate for the two schedule types, but response rate was higher with than without the four-response requirement. Analysis of log survivor plots of interresponse times showed that key poking occurred in bouts. The rate of initiating bouts increased as a function of reinforcer rate but was either unaffected or was decreased by adding the four-response requirement. Within-bout response rate was insensitive to reinforcer rate and only inconsistently affected by the four-response requirement. For both kinds of schedule, the ratio of bout time to between-bout pause time was approximately a power function of reinforcer rate, with exponents above and below 1.0.

Animals↗
PubMed2006

The effects of delayed reinforcement on variability and repetition of response sequences.

Four experiments examined the effects of delays to reinforcement on key peck sequences of pigeons maintained under multiple schedules of contingencies that produced variable or repetitive behavior. In Experiments 1, 2, and 4, in the repeat component only the sequence right-right-left-left earned food, and in the vary component four-response sequences different from the previous 10 earned food. Experiments 1 and 2 examined the effects of nonresetting and resetting delays to reinforcement, respectively. In Experiment 3, in the repeat component sequences had to be the same as one of the previous three, whereas in the vary component sequences had to be different from each of the previous three for food. Experiment 4 compared postreinforcer delays to prereinforcement delays. With immediate reinforcement sequences occurred at a similar rate in the two components, but were less variable in the repeat component. Delays to reinforcement decreased the rate of sequences similarly in both components, but affected variability differently. Variability increased in the repeat component, but was unaffected in the vary component. These effects occurred regardless of the manner in which the delay to reinforcement was programmed or the contingency used to generate repetitive behavior. Furthermore, the effects were unique to prereinforcement delays.

Animals↗
PubMed1980

The value of repetition and reinforcement in improving oral hygiene performance.

The purpose of this study was to assess the value of including repetition and reinforcement in a dental health education program for school children. Sixty-one pupils, 11 to 13 years of age, were divided into three groups according to room assignments. Group I (control) received no oral hygiene lectures or instructions until the conclusion of the experiment. Group 2 (nonreinforced) received one lecture and a toothbrushing lesson, but no repetition or reinforcement. Group 3 (reinforced) received the same program as Group 2 on the initial visit and also received two additional visits for repetition and reinforcement of the lectures and instructions, plus a final summary lecture. Six visits were conducted at intervals of 0, 1, 5, 3, 8, 20 and 52 weeks, following a double-blind experimental format. PHP scores were obtained on all subjects on each of the six visits. It was concluded that the repetition and reinforcement components of this dental health education program were of significant value in improving the oral hygiene performance of the school children over a period of 1 year. The findings provide evidence of the desirability of incorporating these concepts in plaque-control program.

Adolescent↗
PubMed1979

An indirect technique for establishing preferences for categories of reinforcement for severely and profoundly retarded individuals.

The development of a reinforcement survey hierarchy is described for programming severely and profundly retarded individuals. The survey identifies reinforcement preferences of severely and profoundly retarded individuals by means of an indirect categorical technique. The categorical technique views reinforcement as being educationally, environmentally, and developmentally characteristic of severely and profoundly retarded individuals. The survey is a preliminary step to more direct approaches to reinforcement, such as sampling or use of multiple reinforcements. Field data are discussed.

Adolescent↗
PubMed1987

Behavioral effects of microwave reinforcement schedules and variations in microwave intensity on albino rats.

The objective of this exploratory investigation was to determine the interactive effects of fixed-ratio scheduling of microwave reinforcement in tandem with changes in microwave intensity. Nine albino rats were conditioned to regulate their thermal environment with microwave radiation while living in a Skinner (operant conditioning) Box in which the ambient temperature was about 27.13 degrees F at the beginning of the session. Each rat obtained a 6-sec. exposure of microwave radiation on a fixed-ratio schedule of MW reinforcement, the values of which varied from FR-1 to FR-30. Intensities of MW radiation were 62.5 W, 125 W, 250 W, and 437.5 W. Sessions lasted for 8 to 9 hr. over an approximate 13-mo. period. The effects of the intensity of microwave reinforcement varied as a function of the ratio value of the schedule used. Continuous reinforcement (FR-1) produced the lowest over-all rates, whereas FR-15, and FR-25 produced the highest over-all rates. Relatively higher thermal-behavior rates occurred under 62.5 W than under any of the other MW intensities for FR-1, FR-15, and FR-25, whereas FR-10 and FR-30 ratios produced intermediate rates of thermal responding which were constant for all values of MW intensity. These data are explained in terms of interactive effects between the "local" satiation or deprivation properties of the MW intensity and the ratio requirements of the schedule of MW reinforcement.

Animals↗
PubMed1994

Japanese high school and college students' responses to the Adolescent Reinforcement Survey Schedule.

Factor-analyzed correlations among items of the Japanese Adolescent Reinforcement Survey Schedule by Japanese high school students (N = 939) and college students (N = 500) were compared to investigate the changes in reinforcers between mid- and late adolescence, gender differences, and the specific groupings of reinforcers which suggest certain interventions for either or both groups of adolescents. The factor analysis yielded ten interpretable factors in both groups. These factors were similar and did not suggest a dramatic shift in reinforcers between mid- and late adolescence. Items related to heterosexual activities and antisocial behaviors were rated as more pleasurable by males and items related to interpersonal relationships and academic activities were rated as more pleasurable by females. Since both groups of students attach high reinforcement value to interpersonal interaction with peers and family members, interventions focusing on social skills development might be popular and well attended.

Adolescent↗
PubMed1995

Effects of delay of reinforcement with reduction of confinement in the goal-box and elimination of handling immediately following runway traversal.

24 male rats were randomly assigned into one of three groups. The first group was immediately reinforced with food pellets upon entering a wide goal-box area after running down a straight alley. The second group was reinforced with food pellets 10 sec. after they placed their noses above the goal cup. A third group was reinforced 30 sec. after they placed their noses above the goal cup. All animals were given a total of 72 trials (four trials per day). The results indicated that rats given immediate reinforcement ran faster than those with a 10-sec. delay which were faster than those with a 30-sec. delay. These findings suggest that the results of the previous studies were due to delay of reinforcement effects and not confinement in the goal-box or handling following a run.

Animals↗
PubMed2002

On the determinants of induction in responding for sucrose when food pellet reinforcement is upcoming.

Rats' rates of leverpressing for low-concentration liquid-sucrose reinforcers in the first half of an experimental session increase when food pellet, rather than sucrose, reinforcers will be available in the second half. Experiment 1 determined that this induction effect was the outcome of food pellet reinforcement's increasing response rates, not of continued sucrose reinforcement's decreasing them. Experiments 2 and 3 showed that induction was primarily controlled by the conditions of reinforcement in the current session, not by those in the previous one. Experiment 4 showed little evidence that the induction was the outcome of Pavlovian processes. These results suggest that induction may occur because of processes operating at the level of the entire session. They also provide a link to a seemingly related area of study: contrast effects. Some of the results are consistent with what is known about contrast effects, but there are also several, yet unexplained differences.

Animals↗
PubMed1976

[Changes in the cerebral serotonin and noradrenaline levels in the brains of white rats trained with emotionally different reinforcement].

The changes in the serotonin (5-OT) and noradrenaline (NA) content in the brain of rats taught on the emotionally-positive (food) and emotionally-negative (pain) reinforcement were compared. The process of animal learning was accompanied by increase in the biogenic amine level. But when the teaching was conducted on the emotionally-positive reinforcement there was a greater increase in the 5-OT and NA level than in the case of the emotionally negative reinforcement. The process of animal teaching on food reinforcement was accompanied by an elevation of 5-OT chiefly in the cerebral cortex which apparently reflected the active functioning of the 5-OT system. An intensification of the NA system occurred in teaching the animals in the defence situation. A conclusion was thus drawn that the character of the changes in the biogenic amine level in the brain during learning depended on the emotions experienced by the animal (the emotional reinforcement utilized).

Animals↗
PubMed2002

Measuring substance-free and substance-related reinforcement in the natural environment.

The present study sought to provide further evidence for the validity of a modified version of the Pleasant Events Schedule (PES; D. J. MacPhillamy & P. M. Lewinsohn, 1982) designed to measure substance-free and substance-related reinforcement. A sample of 134 young adults completed the modified PES along with measures of substance use and quality of life. The results extend previous research on the modified PES in 3 ways: (a) Information regarding the relationships between substance-related reinforcement and substance use are expanded to include substance-use frequency, quantity, and related negative consequences; (b) relationships between substance-free reinforcement and non-substance-related variables are established; and (c) the distinctiveness of the substance-free and substance-related reinforcement scores is demonstrated. The utility of reinforcement surveys in the study of substance use is discussed, with special emphasis placed on possible treatment implications.

Adult↗
PubMed2003

Expectation enhances the regional brain metabolic and the reinforcing effects of stimulants in cocaine abusers.

The reinforcing effects of drugs of abuse result from the complex interaction between pharmacological effects and conditioned responses. Here we evaluate how expectation affects the response to the stimulant drug methylphenidate in 25 cocaine abusers. The effects of methylphenidate (0.5 mg/kg, i.v.) on brain glucose metabolism (measured by [18F]deoxyglucose-positron emission tomography) and on its reinforcing effects (self-reports of drug effects) were evaluated in four conditions: (1) expecting placebo and receiving placebo; (2) expecting placebo and receiving methylphenidate; (3) expecting methylphenidate and receiving methylphenidate; (4) expecting methylphenidate and receiving placebo. Methylphenidate increased brain glucose metabolism, and the largest changes were in cerebellum, occipital cortex, and thalamus. The increases in metabolism were approximately 50% larger when methylphenidate was expected than when it was not, and these differences were significant in cerebellum (vermis) and thalamus. In contrast, unexpected methylphenidate induced greater increases in left lateral orbitofrontal cortex than when it was expected. Methylphenidate-induced increases in self-reports of "high" were also approximately 50% greater when subjects expected to receive it than when they did not and were significantly correlated with the metabolic increases in thalamus but not in cerebellum. These findings provide evidence that expectation amplifies the effects of methylphenidate in brain and its reinforcing effects. They also suggest that the thalamus, a region involved with conditioned responses, may mediate the enhancement of the reinforcing effects of methylphenidate by expectation and that the orbitofrontal cortex mediates the response to unexpected reinforcement. The enhanced cerebellar activation with expectation may reflect conditioned responses that are not linked to conscious responses.

Adult↗