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1.
Task difficulty in delayed matching-to-sample tasks (DMTS) is increased by increasing the length of a retention interval.
When tasks become more difficult, choice behavior becomes more susceptible to bias produced by unequal reinforcer ratios.
Delaying reinforcement from choice behavior also increases both task difficulty and the biasing effect of unequal reinforcer
probability. Six pigeons completed nine DMTS conditions with retention intervals of 0, 2, 4, 6, and 8 sec, in which reinforcer
delays of 0, 2, and 4 sec were combined with ratios of reinforcer probabilities of .5/.5, .2/.8, and .8/.2 for correct red
and green responses. Discriminability (logd) decreased with both increasing retention interval duration and increasing reinforcer delay. Sensitivity to reinforcement,
the tendency for ratios of choice responses to follow unequal reinforcer probabilities, also increased as a function of both
increasing retention interval and increasing reinforcer delay. The result is consistent with the view that remembering in
DMTS tasks is a discriminated operant in which increasing task difficulty increases sensitivity to reinforcement. 相似文献
2.
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
3.
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
4.
Henry Tobin A. W. Logue John J. Chelonis Kimberly T. Ackerman Jack G. May 《Learning & behavior》1996,24(2):168-174
Two experiments tested two cynomolgus monkeys’ self-control—choice of a longer, more delayed reinforcer over a shorter, less delayed reinforcer. In Experiment 1, subjects exhibited significant selfcontrol in a procedure in which reinforcer amounts and delays were held constant throughout a condition. In Experiment 2, subjects exhibited significantly greater sensitivity to variation in reinforcer amount than to variation in reinforcer delay in a procedure in which the reinforcer delay associated with the self-control alternative was adjusted until each macaque was indifferent between the two alternatives. Both experiments indicated that, in laboratory paradigms in which humans show self-control and pigeons and rats show impulsiveness, macaques show self-control. These results are inconsistent with the hypothesis that species differences in self-control are a function of language ability or of specific types of prior training. The results are consistent with the hypothesis that species differences in self-control are related to the ratio of brain size to body weight (a possible indicator of general cognitive ability) or to shared phylogeny. 相似文献
5.
Rats were trained in a three-alternative spatial delayed matching-to-sample task in a starburst maze. Samples consisted of rewarded forced choices of one arm, and retention was indicated by rats’ returning to that arm after a 90-sec delay. If a rat made an error on its first choice, it was returned to the start compartment and allowed a second choice. Unlike in previous experiments with this task, all three arms were available during the animals’ second choices. The rats tended to perseverate in their second choices by returning to the arm that they had erroneously visited on their first choice. In Experiment 1, the accuracy of second choices following first-choice errors was below chance during the first block of sessions, when a 90-sec delay intervened between the first choice and the second choice, and at chance during the second block of sessions, when a short (5–6 see) delay intervened between first and second choices. In Experiment 2, long-delay and short-delay sessions were randomly presented to naive subjects. Similar results were obtained. In both experiments, the tendency to repeat the erroneous first choice was greater when long delays separated the two choices than when short delays were used. The results suggest that rats make their first-choice errors because they erroneously encode or remember the location of the sample and that they base their second choices on the same erroneous-memory. The increase in perseveration at long delays implies some kind of rehearsal-like mechanism that slows forgetting of the memory controlling the first choice. 相似文献
6.
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
7.
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
8.
Wesley J. Kasprow 《Learning & behavior》1987,15(4):412-416
Choice accuracy by rats in a delayed-alternation paradigm was shown to decrease over a 120-sec retention interval. The decrement in choice accuracy was reversed by presentation of the appetitive reinforcer outside of the apparatus during the retention interval. This suggests that the reinforcer served to reactivate the target spatial memory and that the short-term retention deficit in the absence of such memory reactivation was not due to a loss of information. The results are discussed with respect to recent criticisms of memory-reactivation treatments in short-term retention tasks. 相似文献
9.
Two experiments are reported comparing performance in dominant and submissive rats as determined by a food-competition procedure. Ss in Experiment I were either trained to criterion or overtrained before being reversed on a visual discrimination task. Although the two groups did not differ significantly in learning the initial task, the dominant Ss were significantly slower on reversal than the submissives. Experiment II, which utilized a tandem runway, showed that when the reinforcer which maintained the running response was not available in the first goalbox, submissive rats responded with a greater increase in running speed in the second runway than dominant rats. These findings were discussed as reflecting motivational differences between dominant and submissive rats. 相似文献
10.
Delay between choice and receipt of reinforcement (prereinforcer delay) and delay between receipt of reinforcement and the next opportunity to choose (postreinforcer delay) were varied in a discretetrials choice paradigm using four pigeons. The pigeons consistently chose the reinforcer with the smaller prereinforcer delay. Variations in postreinforcer delay did not affect choice unless prereinforcer delays were equal. The results support previous findings that prereinforcer delays contribute disproportionately to the effects of rate of reinforcer access on choice in pigeons. 相似文献
11.
The role of incentive learning in instrumental performance following a shift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and IB, rats trained to perform an instrumental action reinforced with either sucrose or maltodextrin solutions when in a high-deprivation state were subsequently shifted to a low-deprivation state and tested in extinction. This within-state shift in water deprivation reduced instrumental performance only when the animals had been exposed to the reinforcer in the low-deprivation state prior to instrumental training. In Experiment 2, a concurrent training procedure was used to assess whether the change in the value of the reinforcer brought about by preexposurewas mediated by the contingency between the instrumental action and the reinforcer. Preexposure to the reinforcer under the low-deprivation state produced a selective reduction of the performance of the action upon which it was contingent during training when testing was conducted in extinction following a shift from the high- to the low-deprivation state. These experiments provide evidence that animals have to learn about the incentive value of a reinforcer in a particular motivational state through exposure to the reinforcer in that state. 相似文献
12.
Bonnie M. Perdue Theodore A. Evans David A. Washburn Duane M. Rumbaugh Michael J. Beran 《Learning & behavior》2014,42(2):164-175
Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task—a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated. 相似文献
13.
The role of incentive learning in instrumental performance following an upshift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and 1B, rats trained to perform an instrumental action reinforced by either sucrose or maltodextrin solutions when in a low-deprivation state were shifted to a high-deprivation state and tested in extinction. This shift in water deprivation increased performance only if the animals had been exposed to the reinforcer in the high-deprivation state prior to testing. In Experiment 2, the role of the instrumental contingency in mediating the preexposure effect observed in the first two studies was examined by training rats to make two instrumental actions for different outcomes. The preexposure experience with the outcomes produced a relative increase in performance of the action reinforced with the incentive preexposed in the high-deprivation state when a choice between the two response alternatives was conducted in that state. These experiments support the conclusion that instrumental performance following revaluation of the reinforcer by an upshift in the level of thirst depends on a process of incentive learning. 相似文献
14.
The effect of food deprivation level at the time of initial exposure to a subsequent food reinforcer was investigated in two experiments. In Experiment 1, deprivation at the time of initial exposure influenced the subsequent acquisition and extinction of an instrumental response. In Experiment 2, the residual deprivation effect associated with a reduction in deprivation level occurred only when rats initially experienced the reinforcer at a high, as compared with a low, deprivation level. Results were discussed in terms of the assumption that the limits of incentive generated by a reinforcer are influenced by the deprivation state at the time of first exposure to that reinforcer. 相似文献
15.
We explored response rate as a possible mediator of learned stimulus equivalence. Five pigeons were trained to discriminate
four clip art pictures presented during a 10-sec discrete-trial fixed interval (FI) schedule: two paired with a one-pellet
reinforcer, which supported a low rate of responding, and two paired with a nine-pellet reinforcer, which supported a high
rate of responding. After subjects associated one stimulus from each of these pairs with a discriminative choice response,
researchers presented two new clip art stimuli during a 10-sec FI: one trained with a differential reinforcement of low rate
schedule (DRL) after the FI and the other trained with a differential reinforcement of high rate schedule (DRH) after the
FI. Each of the stimuli that were withheld during choice training was later shown to see if the choice responses would transfer
to these stimuli. The results suggest that response rate alone does not mediate learned stimulus equivalence. 相似文献
16.
Robert A. Rosellini 《Learning & behavior》1978,6(2):155-159
This article reports the reinforcer generality of the interference effect resulting from exposure to inescapable shock. In Experiment 1, rats that received inescapable shock showed weak interference with the acquisition of an appetitive operant compared to animals exposed either to escapable or no shock. In Experiment 2, the response-reinforcer contingency was degraded by introducing a 1-sec delay of reinforcement on the appetitive task. Inescapable shock produced much stronger interference with the acquisition of the operant response than in Experiment 1. The results demonstrate reinforcer generality of the debilitating effects produced by inescapable shock. 相似文献
17.
Amelia Mañá 《Cultura y Educación》2013,25(1):184-202
AbstractThis paper is a review of studies about processes and secondary school students’ difficulties with these processes when they use information to answer questions. The PISA program uses this kind of task-oriented reading situation to evaluate reading literacy, which is also a common reading situation in educational settings. Four key strategies are identified to successfully perform this kind of task: decide how to read the information, comprehend the task, decide when to search for information in order to solve the task, and self-regulate that search process. Moreover, this paper provides accurate information about the students’ difficulties in becoming skilled readers when they use information to answer questions. This information might help teachers and educational counselors in the design of interventions to improve reading literacy in schools. 相似文献
18.
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
19.
Autoshaping procedures with pigeons were used to assess the susceptibility of unconditioned response (UR) activity to Pavlovian relations between stimulus and reinforcer events. Foodpeck latency (a measure of UR activity) was investigated as a function of the interval between stimulus (keylight) and reinforcer (grain) presentations, and of the stimulus-reinforcer contingency, that is, the conditional probabilities of reinforcer delivery in the presence and absence of the stimulus. Four experiments indicated that food-peck latency was sensitive to both manipulations. Generally, conditions that led to higher keypeck rates were associated with shorter latencies. Thus, UR potentiation was demonstrated. However, when the bird’s location prior to grain delivery was fixed by imposing a keypeck-reinforcer contingency, UR potentiation vanished; it then reappeared when the location constraint was removed. Visual observations supported the conclusion that food-peck latency effects were mediated by approach/withdrawal tendencies generated by the stimulus-reinforcer relation. Implications of these results for expectancy theory are discussed. 相似文献
20.
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