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Query: UMLS:C0598853 (forgetting)
 3,232 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A computer-simulation model (AL) was developed for molecular and molar operant conditioning data. AL assumes a simple forgetting rule and all-or-nothing associations between memory representations of responses and reinforcers. AL describes acquisition and steady-state behavior in both concurrent interresponse time (IRT) schedules and in ordinary concurrent schedules. It describes functions relating the relative frequency of an IRT to IRT duration and to reinforcement frequency. AL accurately predicts for ordinary concurrent variable-interval schedules that the log ratio of responses to the two alternatives is a linear function of the log ratio of the reinforcers they deliver, and that the slope of this straight line approximates the degree of undermatching that characterizes the behavior of real animals. In addition, AL successfully describes the fact that in real data of Nevin, Heyman, and others, the probability of a changeover from one response to the other is roughly independent of the number of consecutive responses to the same alternative preceding the changeover. A previous version of AL assimilated data on temporal psychophysics, such as that animals bisect two temporal intervals at the geometric mean, and that the Weber fraction in DRL schedules is approximately constant. AL therefore describes transient and steady-state molecular and molar performances as well as data on temporal psychophysics.
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PMID:Timing, learning, and forgetting. 658 99

A theory of attending and reinforcement in conditional discriminations is extended to working memory in delayed matching to sample by adding terms for disruption of attending during the retention interval. Like its predecessor, the theory assumes that reinforcers and disruptors affect the independent probabilities of attending to sample and comparison stimuli in the same way as the rate of overt free-operant responding as suggested by Nevin and Grace, and that attending is translated into discriminative performance by the model of Davison and Nevin. The theory accounts for the effects of sample-stimulus discriminability and retention-interval disruption on the levels and slopes of forgetting functions, and for the diverse relations between accuracy and sensitivity to reinforcement reported in the literature. It also accounts for the effects of reinforcer probability in multiple schedules on the levels and resistance to change of forgetting functions; for the effects of reinforcer probabilities signaled within delayed-matching trials; and for the effects of reinforcer delay, sample duration, and intertrial-interval duration. The model accounts for some data that have been problematic for previous theories, and makes testably different predictions of the effects of reinforcer probabilities and disruptors on forgetting functions in multiple schedules and signaled trials.
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PMID:A theory of attending, remembering, and reinforcement in delayed matching to sample. 1797 Apr 20

Traditional theories of delayed matching-to-sample performance do not predict that accuracy will improve when absolute levels of reinforcement are increased. This prediction emerges only when reinforcement context is considered (J. A. Nevin, M. Davison, A. L. Odum, & T. A. Shahan, 2007). To provide quantitative data, the authors factorially manipulated between conditions the probability and duration of reinforcement for correct choices by pigeons. In Experiment 1, increasing the value of either variable improved initial discriminability of the forgetting functions, but did not affect the rate of forgetting. In Experiment 2, initial discriminability covaried with changes in choice immediacy and trial completion rate, suggesting a relationship with response strength consistent with Nevin et al.'s behavioral momentum model. Adding reinforcement context to K. G. White and J. T. Wixted's (1999) model also generates predictions consistent with the present experiments and with the effects of manipulating extraneous reinforcement. The inclusion of reinforcement context thus improves predictions of delayed matching-to-sample performance.
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PMID:Reinforcer probability, reinforcer magnitude, and the reinforcement context for remembering. 1936 32

The effects of reinforcement on delayed matching to sample (DMTS) have been studied in two within-subjects procedures. In one, reinforcer magnitudes or probabilities vary from trial to trial and are signaled within trials (designated signaled DMTS trials). In the other, reinforcer probabilities are consistent for a series of trials produced by responding on variable-interval (VI) schedules within multiple-schedule components (designated multiple VI DMTS). In both procedures, forgetting functions in rich trials or components are higher than and roughly parallel to those in lean trials or components. However, during disruption, accuracy has been found to decrease more in rich than in lean signaled DMTS trials and, conversely, to decrease more in lean than in rich multiple VI DMTS components. In the present study, we compared these procedures in two groups of pigeons. In baseline, forgetting functions in rich trials or components were higher than and roughly parallel to those in lean trials or components, and were similar between the procedures. During disruption by prefeeding or extinction, accuracy decreased more in rich signaled DMTS trials, whereas accuracy decreased more in lean multiple VI DMTS components. These results replicate earlier studies and are predicted by a model of DMTS from Nevin, Davison, Odum, and Shahan (2007).
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PMID:Delayed matching to sample: reinforcement has opposite effects on resistance to change in two related procedures. 2220 22

Atypical forgetting functions have been demonstrated in several recent studies of delayed matching to sample, in which experimental conditions are altered partway through the retention interval. The forgetting functions are atypical in that accuracy or discriminability is not always a negatively accelerated monotonic function of increasing retention interval duration, but may increase at later times in the retention interval. Atypical forgetting functions reflect changes in levels of discrimination. A switch from a lower level to a higher level of discrimination, or vice versa, can occur at any time in the retention interval. The behavioral theories of remembering proposed by Nevin, Davison, Odum, and Shahan (2007), and White and Brown (2014), offer quantitative predictions of forgetting functions that differ in intercept or slope. Both theories are able to account for atypical forgetting functions, by assuming time-independent changes in the mediating effect of attending to sample and comparison stimuli (in Nevin et al.'s model) or in the direct effect of the context of reinforcement of the conditional discrimination (in White & Brown's model). Despite differences in their main assumptions, the theories have an edge over any theory that assumes that forgetting is time-dependent.
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PMID:Direct remembering, mediated remembering, and atypical forgetting functions. 2929 63