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At least 145 records · Page 8Linked to original sources
PubMed1985

Sensitivity of time allocation to concurrent-schedule reinforcement.

Four pigeons were trained on concurrent variable-interval schedules programmed on a center response key, with access to those schedules controlled by responses on left or right side keys. Two procedures were used. In one, the pigeon was given limited access, in that each side-key response produced 3-s access to a center-key schedule, and in the other procedure, access was unlimited. Data were analyzed using the generalized matching law. Comparison of sensitivities to reinforcement of interchangeover time for both procedures showed them to be of similar magnitude. Response sensitivities were also similar in magnitude for both procedures. From the limited-access procedure a second time measure that was available, switched-in time, was relatively uncontaminated by time spent emitting behavior other than key pecking. Sensitivities to reinforcement for the switched-in time measure were always smaller than interchangeover-time sensitivities for either procedure, and were approximately equal to response sensitivities for the limited-access procedure. Two other access times (5 and 7.5 s) were studied to validate the choice of 3 s as the main access time. These results indicate that when time spent emitting other behavior is excluded from interchangeover time, time and response sensitivities will be approximately equal.

Journal Article↗
PubMed1978

Matching with a key-peck response in concurrent negative reinforcement schedules.

In the absence of responding, pigeons were shocked under a variable-time schedule. Responses on either of two keys occasionally produced one minute of shock-free time. That is, pigeons' key pecks were reinforced with shock-free time under concurrent variable-interval schedules. The relative frequency of access to the one-minute shock-free periods was systematically manipulated. Pigeons tended to match both relative response rate and proportion of time spent on each key to the relative frequency of the shock-free periods. A best-fit linear regression equation accounted for over 95% of the variance in both relative response rate and time allocation. The data paralleled closely the results of concurrent schedules of positive reinforcement. These findings are consistent with a description of reinforcement as a transition to a higher-valued situation and suggest that common laws govern choice for both positive and negative reinforcement.

Journal Article↗
PubMed1980

Effects of pimozide on lever pressing behavior maintained on an intermittent reinforcement schedule.

Lever pressing for food on a variable interval (2.5 min) schedule was challenged by pretreatment with a 1.0 mg/kg dose of the dopamine receptor blocker pimozide. Large decreases in response rate were recorded even during the first few minutes of the test session before the rats had received any reinforcement. Pimozide also caused extinction-like effects, but it was clear, from comparisons between pimozide-treated rats that were rewarded and pimozide-treated rats that were not rewarded, that the rewarding effects of food were not totally blocked. It is suggested that an important aspect of the pimozide-produced response decrement is its effect on the incentive motivational properties of food-associated apparatus cues known to be important in sustaining responding under extinction and partial reinforcement conditions.

Animals↗
PubMed1994

Effects of different accessibility of reinforcement schedules on choice in humans.

Based on the delay-reduction hypothesis, a less profitable schedule should be rejected if its duration exceeds the mean delay to reinforcement. It should be accepted if its duration is shorter than the mean delay. This was tested for humans, using a successive-choice schedule. The accessibility of the less profitable (variable-interval 18 s) schedule was varied by changing the duration (in terms of a fixed interval) of the waiting-time component preceding its presentation. Forty-eight students were randomly assigned to three groups. In Phase 1, the duration of the less profitable schedule equaled the mean delay to reinforcement in all groups. In Phase 2, waiting time preceding the less profitable schedule was reduced in Group 1 and increased in Group 2. Thus, the schedule was correlated either with a relative delay increase (Group 1) or a delay reduction (Group 2). In Group 3, conditions remained unchanged. As predicted, acceptance of the less profitable schedule decreased in Group 1 and increased in Group 2. The increased acceptance in Group 2 was accompanied by a decreased acceptance of the more profitable (variable-interval 3 s) schedule, resembling a pattern of negative contrast. Response rates were higher under the component preceding (a) the more profitable schedule in Group 1 and (b) the less profitable schedule in Group 2. Implications for the modification of human choice behavior are discussed.

Journal Article↗
PubMedDate not supplied

[Self-stimulation of phylogenetically new and ancient hypothalamic structures when reinforcement schedules are changed].

The following two types of reaction are exhibited by self-stimulating rats following a transition from the regimen of preference (free) to that of fixed series of stimuli: I. increased frequency of pressings with simultaneous shortening of their duration, approaching the duration of fixed series; II. reduced frequency of pressings with their longer duration. Of the two studied hypothalamic areas, the former type of reaction is exhibited predominantly in the self-stimulation points located in the lateral hypothalamic area, while the latter type - in the lateral preoptic area. Different strategy of the animals' behaviour observed during the change of reinforcement routines is discussed with regard to different levels of integration of emotionally-positive mechanisms of brain structures of phylogenetically different age.

Animals↗
PubMed2000

A method for identifying satiation versus extinction effects under noncontingent reinforcement schedules.

We evaluated one method for determining whether response suppression under noncontingent reinforcement (NCR) is a function of satiation or extinction. Three individuals with developmental disabilities who engaged in self-injurious behavior (SIB) or aggression participated. Results of functional analyses indicated that their problem behavior was maintained by social-positive reinforcement. NCR procedures, individualized for each participant, were implemented in a multiple baseline across subjects design and were associated with decreases in all participants' problem behavior. Identification of the mechanism by which NCR produced these effects was based on examination of cumulative records showing response patterns during and immediately following each NCR session. Satiation during NCR should lead to a temporary increase in responding during the post-NCR (extinction) period due to a transition from the availability to the unavailability of reinforcement (satiation to deprivation). Alternatively, extinction during NCR should reveal no increase in responding during the extinction period because the contingency for the problem behavior would remain unchanged and the transition from satiation to deprivation conditions would be irrelevant. Results suggested that the operative mechanisms of NCR were idiosyncratic across the 3 participants and appeared to change during treatment for 1 of the participants.

Adolescent↗
PubMedDate not supplied

Comparison of reinforcement schedules in the reduction of stereotypy with supported routines.

The rates and durations of stereotypic behaviors in four adolescents with severe mental retardation were measured during two daily vocational training sessions and during contiguous periods of leisure in their special education classrooms. Vocational training was conducted in two different tasks, alternating across days. The task requirements for each participant were matched to each participant's learning and performance characteristics. The participants were exposed to a fixed ratio schedule of tokens exchangeable for food items on one task and to a variable interval schedule for the same consequences on the second task. The schedules were chosen as an initial test of a matching-law based prediction by Myerson and Hale (1984): Variable interval reinforcement for adaptive behavior will produce less allocation of responding to maladaptive behavior than will a ratio-based intervention. When work performances stabilized, the schedules of token delivery were reversed across the tasks and performances again stabilized. Results are reported for periods when work performances met stability criteria. Stereotypy occurred more during leisure than during vocational training under either schedule. The major differences in stereotypy between leisure and vocational training were differences in episode length rather than rate of onset. Onset of stereotypy in vocational training, however, occurred at higher rates under the interval schedule than under the ratio schedule in both tasks. The results are discussed in terms of Myerson and Hale's prediction and implications for further research and application.

Adolescent↗
PubMed1981

Contributions of reinforcement schedule histories to our understanding of drug effects in human subjects.

Like other reinforcing stimuli, drug effects may vary with the reinforcement history of an individual. Data are presented which demonstrate that histories contribute to individual differences in response to reinforcement contingencies and modification of maladaptive behavioral persistence. Possible relevance of these findings to an understanding of drug effects in humans is discussed.

Adult↗
PubMed1992

Opioid-induced response-rate decrements in pigeons responding under variable-interval schedules: reinforcement mechanisms.

Opioid drugs may produce some of their behavioral effects by altering the effectiveness of reinforcing events. The present investigation examined effects of two opioids (methadone and buprenorphine) on pigeons' key-pecking. Different reinforcement rates were arranged using five variable-interval (VI) food-presentation schedules, permitting an application of Heyman's Matching Law analysis and Nevin's Resistance to Change Hypothesis to behavioral actions of opioid drugs. Key-pecking by four pigeons was reinforced by 3-s access to mixed grain under a five component multiple VI schedule. VI values used were 5, 10, 30, 75 and 150s. Each component was in effect for 5min followed by 1min of darkness. Peck rates were high under the VI5-s and VI10-s schedules. As the mean interval value increased, peck rates decreased. Methadone (0.5, 1.5, 2.5, 3.75, and 5.0mg/kg) and buprenorphine (0.25, 0.5, 1.0, 3.0, and 5.0mg/kg), administered 30min prior to experimental sessions, dose dependently decreased peck rates in all subjects. Peck rates under longer VI schedules (75 and 150s) tended to be more greatly disrupted than those maintained under shorter VI schedules (e.g. 10s). Dose-by-dose analysis of key-pecking rate changes under each schedule, and analysis of drug-induced changes in Matching Law parameters suggest that peck rate decreases resulted, in part, from decrements in the reinforcer's ability to maintain behavior.

Journal Article↗
PubMed1968

Effects of candy and social reinforcement, instructions, and reinforcement schedule leaning on the modification and maintenance of smiling.

Two retarded boys exhibited abnormally low rates of smiling. In Exp. I, the frequency of a boy's smiling was first increased with candy reinforcement, but the frequency of the response did not decrease when candy reinforcement was terminated. When the subject wore a sign designed to make social interactions contingent on not-smiling, the frequency of smiling decreased. The sign was then changed to make social interactions contingent on smiling and the rate of smiling increased. In Exp. II, a second boy initially never smiled. Establishment of a contingency for candy reinforcement did not increase this zero response rate. Instructing the child to smile initially increased smiling, but the instructions then became progressively more ineffective. Candy reinforcement increased the rate of smiling to a normal range, but the rate of the response promptly decreased when this reinforcement was discontinued. Continuous candy reinforcement was again employed to increase the response rate and then progressively leaner schedules of variable-ratio candy reinforcement were employed. Consequently, the rate of smiling did not decrease when candy reinforcement was again eliminated. Subsequently, signs were employed to regulate social interactions and the rate of smiling was shown to be controlled by these interactions serving as reinforcers.

Journal Article↗
PubMed1995

Preliminary comparison of two negative reinforcement schedules to reduce self-injury.

This study compared the effectiveness of differential negative reinforcement of other behavior (DNRO) and alternative behavior (DNRA) for reducing self-injurious tantrums maintained by escape from demands in a 4-year-old girl with severe retardation. Both DNRA and DNRO reduced self-injury and increased independent performance of two tasks (tooth brushing and bathing); however, improvement on both measures was greater with the DNRA intervention.

Journal Article↗