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1.
Jay Moore 《Learning & behavior》1976,4(4):441-450
Pigeons responded on a two-key concurrent chains choice procedure with the same level of percentage reinforcement on each key. During the initial links, a choice response on either key occasionally produced a conditioned reinforcer—which on one key was associated with a 15-sec, and on the other key with a 30-sec, interreinforcement interval—or an extinction stimulus. In Part 1, the initial links were equal. With successive decreases in the probability of a reinforcer, choice shifted from preference for the 15-sec terminal link toward indifference. In Part 2, the initial links were unequal and were arranged so that the shorter initial link preceded the 30-sec terminal link. At a high probability of a reinforcer, the pigeons again preferred the 15-sec terminal link. However, at a low probability, the pigeons reversed and preferred the alternate key. It was concluded that the conditioned reinforcers tended to become functionally equivalent at a low probability of a reinforcer, despite the nominally different interreinforcement intervals, with the result that choice was then modulated by the relative size of the initial links. The data are inconsistent with the view that choice and the strength of conditioned reinforcers are isomorphic with the reduction in delay to reward correlated with terminal link stimuli. 相似文献
2.
Stimuli associated with primary reinforcement for instrumental behavior are widely believed to acquire the capacity to function as conditioned reinforcers via Pavlovian conditioning. Some Pavlovian conditioning studies suggest that animals learn the important temporal relations between stimuli and integrate such temporal information over separate experiences to form a temporal map. The present experiment examined whether Pavlovian conditioning can establish a positive instrumental conditioned reinforcer through such temporal integration. Two groups of rats received either delay or trace appetitive conditioning in which a neutral stimulus predicted response-independent food deliveries (CS1→US). Both groups then experienced one session of backward second-order conditioning of the training CS1 and a novel CS2 (CS1–CS2 pairing). Finally, the ability of CS2 to function as a conditioned reinforcer for a new instrumental response (leverpressing) was assessed. Consistent with the previous demonstrations of temporal integration in fear conditioning, a CS2 previously trained in a trace-conditioning protocol served as a better instrumental conditioned reinforcer after backward second-order conditioning than did a CS2 previously trained in a delay protocol. These results suggest that an instrumental conditioned reinforcer can be established via temporal integration and raise challenges for existing quantitative accounts of instrumental conditioned reinforcement. 相似文献
3.
Mazur JE 《Learning & behavior》2007,35(3):169-176
Rats chose between alternatives that differed in the number of reinforcers and in the delay to each reinforcer. A left leverpress
led to two reinforcers, each delivered after a fixed delay. A right leverpress led to one reinforcer after an adjusting delay.
The adjusting delay was increased or decreased many times in a session, depending on the rat’s choices, in order to estimate
an indifference point& #x2014;a delay at which the two alternatives were chosen about equally often. Both the number of reinforcers
and their individual delays affected the indifference points. The overall pattern of results was well described by the hyperbolic-decay
model, which states that each additional reinforcer delivered by an alternative increases preference for that alternative
but that a reinforcer’s effect is inversely related to its delay. Two other possible delay-discounting equations, an exponential
equation and a reciprocal equation, did not produce satisfactory predictions for these data. Adding an additional free parameter
to the hyperbolic equation as an exponent for delay did not appreciably improve the predictions, suggesting that raising delay
to some power other than 1.0 was unnecessary. The results were qualitatively similar to those from a previous experiment with
pigeons (Mazur, 1986), but quantitative differences suggested that the rates of delay discounting were several times slower
for rats than for pigeons. 相似文献
4.
Mazur JE 《Learning & behavior》2008,36(4):301-310
Pigeons responded in a successive-encounters procedure that consisted of a search period, a choice period, and a handling period. The search period was either a fixed-interval or a mixed-interval schedule presented on the center key of a three-key chamber. Upon completion of the search period, the center key was turned off and the two side keys were lit. A pigeon could either accept a delay followed by food (by pecking the right key) or reject this option and return to the search period (by pecking the left key). During the choice period, a red right key represented the long alternative (a long handling delay followed by food), and a green right key represented the short alternative (a short handling delay followed by food). The experiment consisted of a series of comparisons for which optimal diet theory predicted no changes in preference for the long alternative (because the overall rates of reinforcement were unchanged), whereas the hyperbolic-decay model predicted changes in preference (because the delays to the next possible reinforcer were varied). In all comparisons, the results supported the predictions of the hyperbolic-decay model, which states that the value of a reinforcer is inversely related to the delay between a choice response and reinforcer delivery. 相似文献
5.
We present an algebraic model of resistance to extinction that is consistent with research on resistance to change. The model assumes that response strength is a power function of reinforcer rate and that extinction involves two additive, decremental processes: (1) the termination of the reinforcement contingency and (2) generalization decrement resulting from reinforcer omission. The model was supported by three experiments. In Experiment 1, 4 pigeons were trained on two-component multiple variable-interval (VI) 60-sec, VI 240-sec schedules. In two conditions, resistance to change was tested by terminating the response-reinforcer contingency and presenting response-independent reinforcers at the same rate as in training. In two further conditions, resistance to change was tested by prefeeding and by extinction. In Experiment 2, 6 pigeons were trained on two-component multiple VI 150-sec schedules with 8-sec or 2-sec reinforcers, and resistance to change was tested by terminating the response-reinforcer contingency in three conditions. In two of those conditions, brief delays were interposed between responses and response-independent reinforcers. In both Experiments 1 and 2, response rate was more resistant to change in the richer component, except for extinction in Experiment 1. In Experiment 3, 8 pigeons were trained on multiple VI 30-sec, VI 120-sec schedules. During extinction, half of the presentations of each component were accompanied by a novel stimulus to produce generalization decrement. The extinction data of Experiments 1 and 3 were well described by our model. The value of the exponent relating response strength and reinforcement was similar in all three experiments. 相似文献
6.
Terry W. Belke 《Learning & behavior》2000,28(4):332-343
Previous research showed that sucrose and wheel-running reinforcement of leverpressing generate different response rate asymptotes. To investigate the basis of this difference, the present study assessed the role of inhibitory after-effects and excitatory stimulus effects on measures of responding in rats exposed to fixed-interval schedules that randomly produced either sucrose or wheel-running reinforcers. Different discriminative stimuli were associated with each reinforcer type. Inhibitory aftereffects and excitatory stimulus effects were assessed by the pattern of postreinforcement pauses and local response rates across the four different combinations of previous and upcoming reinforcer types: wheel-wheel, wheel-sucrose, sucrose-wheel, and sucrose-sucrose. Results showed that, regardless of the prior type of reinforcer, response rates were higher and pauses were shorter in the presence of a stimulus signaling sucrose reinforcement. This suggests that differences in response rate asymptotes generated by these qualitatively different reinforcers may have more to do with differences in excitatory stimulus effects than with inhibitory after-effects. 相似文献
7.
Ben A. Williams 《Learning & behavior》1994,22(4):442-457
Rats were trained on a discriminated operant barpressing task according to a standard blocking design. In some conditions, the reinforcer was changed between the pretraining and compound conditioning phases; for other conditions, the reinforcer remained the same across phases. In three separate experiments using both between- and within-subject designs, strong blocking effects occurred regardless of the change in the reinforcer. In a fourth experiment, a multiple schedule of reinforcement was used in which response-independent reinforcers were superimposed on the schedule of response-contingent reinforcers. The degree of response suppression caused by the free reinforcer was greater when the free reinforcers were the same as the response-contingent reinforcers than when they were different. The role played by the reinforcer identity in contingency experiments thus appears to be different from the role it plays in blocking experiments. 相似文献
8.
9.
Pigeons pecked keys on concurrent-chains schedules that provided a variable interval 30-sec schedule in the initial link.
One terminal link provided reinforcers in a fixed manner; the other provided reinforcers in a variable manner with the same
arithmetic mean as the fixed alternative. In Experiment 1, the terminal links provided fixed and variable interval schedules.
In Experiment 2, the terminal links provided reinforcers after a fixed or a variable delay following the response that produced
them. In Experiment 3, the terminal links provided reinforcers that were fixed or variable in size. Rate of reinforcement
was varied by changing the scheduled interreinforcer interval in the terminal link from 5 to 225 sec. The subjects usually
preferred the variable option in Experiments 1 and 2 but differed in preference in Experiment 3. The preference for variability
was usually stronger for lower (longer terminal links) than for higher (shorter terminal links) rates of reinforcement. Preference
did not change systematically with time in the session. Some aspects of these results are inconsistent with explanations for
the preference for variability in terms of scaling factors, scalar expectancy theory, risk-sensitive models of optimal foraging
theory, and habituation to the reinforcer. Initial-link response rates also changed within sessions when the schedules provided
high, but not low, rates of reinforcement. Within-session changes in responding were similar for the two initial links. These
similarities imply that habituation to the reinforcer is represented differently in theories of choice than are other variables
related to reinforcement. 相似文献
10.
R. J. Madigan 《Learning & behavior》1978,6(2):193-197
Three rats responding on fixed-interval schedules received either 1 or 4 pellets at the end of 2-min intervals. Five experimental conditions manipulated the relative probabilities of these two reinforcers. Response rates following the 1-pellet reinforcer were always higher than the rates following the 4-pellet reinforcer. The rates after the 1-pellet reinforcer were also highest in those experimental conditions where it was delivered with low probability. Contrast effects were observed when two sequential fixed intervals differed in reinforcer magnitudes. It was concluded that the context of reinforcement as well as the specific reinforcer magnitude affects responding under fixed-interval schedules. 相似文献
11.
Sharon Damon T. Chris Riley-Tillman Catherine Fiorello 《Journal of educational and psychological consultation》2013,23(1):31-53
Reinforcement-based interventions, the most frequently used treatments for school-age children, rely on accurately identifying stimuli that will serve to reinforce appropriate classroom behavior. Research has consistently demonstrated that the results from a forced-choice pairing procedure are the best predictors of reinforcing stimuli. Interestingly, systematic evaluation of potential reinforcers is rarely implemented in the school consultation setting. Considering the importance of the reinforcer on reinforcement-based interventions, and the literature focusing on the significance of the selection procedure on accurately identifying a reinforcer, this is concerning. The purpose of these two studies was to examine the effectiveness of identifying reinforcing stimuli for students in the consultation setting using two different methods: stimulus forced-choice and asking the teacher to identify potential reinforcers. The effectiveness of the selected stimuli as reinforcers was studied on two student outcomes: academic production and on-task behavior. The results of the two studies suggested that the reinforcers selected using a forced-choice procedure were more effective than the reinforcers selected from a teacher-identification procedure. Further, results indicated that although stimuli derived from both reinforcer assessment methods were useful at increasing rates of desired behavior, stimuli derived from the forced-choice reinforcer assessment were more consistently effective. 相似文献
12.
Two experiments examined the effects of extended training on the development of response-reinforcer associations. Rats were trained by using various food reinforcers to make multiple instrumental responses. Subsequently, those reinforcers were devalued by being paired with a toxin. The presence of response-reinforcer associations was inferred from the decrease in the likelihood of a response following devaluation of its reinforcer. Such response-reinforcer associations are known to contribute to performance after moderate amounts of training. These experiments addressed the question of whether the contribution of those associations remains constant, increases, or decreases with more extended training. Experiment 1 found that even after a response had been extensively trained with one reinforcer, the substitution of a new reinforcer produced new associations between the response and that new reinforcer. After extended training, a response continued to acquire new associations with a reinforcer, as indexed by the impact of a devaluation procedure. Experiment 2 directly compared the contribution of reinforcers used extensively and moderately with the same response. It found that devaluation of the extensively used reinforcer more effectively reduced performance of the response, suggesting that the associations formed with additional training contribute to performance of the response. These experiments indicate that the contribution of response-reinforcer associations does not decrease but, instead, continues to grow throughout the course of extended instrumental training. 相似文献
13.
In two experiments, pigeons' responding on an extraneous task was explicitly reinforced during delayed matching-to-sample
trials. In Experiment 1, red or green sample stimuli were followed by retention intervals of 0.2, 1, 4, or 12 sec, during
which pecks to a white center key were reinforced with 2.5-sec access to wheat according to extinction, variable-interval
30-sec, and variable-interval 15-sec schedules in different conditions. A proportion of .2, .5, .7, or .9 of subsequent red
or green choice responses that matched the sample were reinforced with 3-sec access to wheat. The result was that increasing
center key reinforcement, or reducing reinforcer probability, lowered overall accuracy. Initial discriminability fell, but
with no change in the rate of forgetting. In Experiment 2, initial discriminability was affected by extraneous reinforcers
that were contingent on center key pecking, but not by noncontingent reinforcers. A plausible conclusion is that initial discriminability
decreases when reinforcers strengthen competing behaviors. 相似文献
14.
Previous research has demonstrated that running in a rotating wheel functions as a reinforcer for leverpressing in rats. In these studies, the pattern of responding was similar to the pattern of responding maintained by consummatory reinforcers, such as food and water. The present study investigated quantitative features of responding maintained by running. In previous experiments in which responses were reinforced according to variable-interval (VI) schedules and food and water served as the reinforcer, the equation for a rectangular hyperbola described the relationship between response rate and reinforcement rate. This experiment tested whether this quantitative regularity also applies to leverpressing maintained by the opportunity to run in a wheel. Fourteen male Wistar rats responded on levers for the opportunity to run. In each session, subjects were exposed to a series of VI schedules. An opportunity to run for 60 sec was the reinforcing consequence. Results showed that response rate was a negatively accelerated function of reinforcement rate, and the relationship between these two variables was described well by the equation for a rectangular hyperbola. To further test the similarity between running and consummatory reinforcers, the response requirement and access were manipulated. In previous experiments with food and water, these types of manipulations differentially changed the two parameters of the hyperbola. A similar pattern of results was obtained with wheel running. Thus, the equation appears to apply to running about as well as it does to consummatory reinforcers. 相似文献
15.
Blocking was investigated in a free-operant procedure by presenting a response-contingent signal prior to reinforcer delivery. At issue was the way in which blocking effects previously reported with this procedure are related to conditioned reinforcement effects, also previously found with similar procedures. Signal presentation decreased response rate when delay of reinforcement was 0 or .5 sec, but the signal increased response rate when the delay of reinforcement was increased to 3 sec. Thus, which effect (blocking or conditioned reinforcement) occurred depended critically on the response-reinforcer interval. 相似文献
16.
Two groups of pigeons were required to generate a fixed sequence of responses on three keys, for example, middle-left-right. One group received a small food reward (SFood) following each correct response except the terminal one, which was followed by a large food reward. The second group received conditioned reinforcement from an overhead light (SLight) for each correct response, with the terminal correct response followed by both SLight and the large food reward. We manipulated length of sequence (3 or 7 responses) and duration of required interresponse interval (IRI; 1 to 9 sec). SLight contingencies generated more accurate performances than did SFood when sequence length was 3 responses but not when it was 7 responses. IRI duration influenced accuracy under the SLight contingencies but not under SFood. These results show that conditioned reinforcers sometimes generate more accurate sequence learning than do primary reinforcers, and that schedule contigencies influence which type of feedback will optimize performance. The results parallel those from the matching-to-sample and conditional discrimination literature. 相似文献
17.
Manipulating experience with the reinforcer, through either home cage presentations of Noyes pellets or availability of the free reinforcer immediately prior to testing, attenuated the preference for earned as opposed to free reinforcers. Similarly, changing the reinforcer to one of a different flavor at testing increased the preference for the noncontingent reinforcer. These results are consistent with an interpretation of earned reinforcer preference which emphasizes the role of the reinforcer as a discriminative signal for further instrumental responding. It is suggested that the tendency to perform instrumental responses for reinforcers when free reinforcers are available can be explained in terms of traditional learning processes. 相似文献
18.
Humans prefer (conditioned) rewards that follow greater effort (Aronson & Mills, 1959). This phenomenon can be interpreted
as evidence for cognitive dissonance (or as justification of effort) but may also result from (1) the contrast between the
relatively greater effort and the signal for reinforcement or (2) the delay reduction signaled by the conditioned reinforcer.
In the present study, we examined the effect of prior force and prior time to produce stimuli associated with equal reinforcement.
As expected, pressing with greater force or for a longer time was less preferred than pressing with less force or for a shorter
time. However, participants preferred the conditioned reinforcer that followed greater force and more time. Furthermore, participants
preferred a long duration with no force requirement over a shorter duration with a high force requirement and, consistent
with the contrast account but not with the delay reduction account, they preferred the conditioned stimulus that followed
the less preferred, shorter duration, high-force event. Within-trial contrast provides a more parsimonious account than justification
of effort, and a more complete account than delay reduction. 相似文献
19.
James E. Mazur 《Learning & behavior》1995,23(1):93-103
Pigeons pecked on two response keys that delivered reinforcers on a variable-interval schedule. The proportion of reinforcers delivered by one key was constant for a few sessions and then changed, and subjects’ choice responses were recorded during these periods of transition. In Experiment 1, response proportions approached a new asymptote slightly more slowly when the switch in reinforcement proportions was more extreme. In Experiment 2, slightly faster transitions were found with higher overall rates of reinforcement. The results from the first session, after a switch in the reinforcement proportions, were generally consistent with a mathematical model that assumes that the strength of each response is increased by reinforcement and decreased by nonreinforcement. However, neither this model nor other similar models predicted the “spontaneous recovery” observed in later sessions: At the start of these sessions, response proportions reverted toward their preswitch levels. Computer simulations could mimic the spontaneous recovery by assuming that subjects store separate representations of response strength for each session, which are averaged at the start of each new session. 相似文献
20.
Two hundred seventh grade Ss were administered a paired comparison scale for the purpose of predicting reinforcer effectiveness of fifteen stimuli. These stimuli were selected from three categories of reinforcement: 1.) verbal and social, 2.) tangible and manipulatable, and 3.) knowledge of progress. Results of the study indicated that the paired comparison scale of determining reinforcing preferences was moderately reliable. On the validation task, Ss performed equally well for the most and least preferred reinforcers. This finding suggests that a S, when selecting from several reinforcers, cannot choose the stimulus which would be most effective in increasing his performance. 相似文献