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The Comparator Hypothesis: A Response Rule for The Expression of Associations

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Abstract

This chapter describes the potential explanatory power of a specific response rule and its implications for models of acquisition. This response rule is called the “comparator hypothesis.” It was originally inspired by Rescorla's contingency theory. Rescorla noted that if the number and frequency of conditioned stimulus–unconditioned stimulus (CS–US) pairings are held constant, unsignaled presentations of the US during training attenuate conditioned responding. This observation complemented the long recognized fact that the delivery of nonreinforced presentations of the CS during training also attenuates conditioned responding. The symmetry of the two findings prompted Rescorla to propose that during training, subjects inferred both the probability of the US in the presence of the CS and the probability of the US in the absence of the CS and they then established a CS–US association based upon a comparison of these quantities. The comparator hypothesis is a qualitative response rule, which, in principle, can complement any model of acquisition.

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... The opposite also occurs and is possible to learn without any change in responding; theories of learning have considered how response changes independently of acquisition training, and how learning can occur without an apparent change in response. Miller and Matzel (1988) provided an approximation to this in the "comparator hypothesis." Miller and Matzel (1988) suggested that when the subject learns, it does not take in consideration how good of a predictor a cue is (as the Rescorla-Wagner model); instead, the organism learns about all the stimuli that are presented together. ...
... Miller and Matzel (1988) provided an approximation to this in the "comparator hypothesis." Miller and Matzel (1988) suggested that when the subject learns, it does not take in consideration how good of a predictor a cue is (as the Rescorla-Wagner model); instead, the organism learns about all the stimuli that are presented together. In other words, contiguity alone is sufficient to produce learning. ...
... The comparator hypothesis (Miller and Matzel 1988), more specifically, states that in every learning situation (when a cue is followed by a consequence or US), the cue is associated with the consequence, but this cue is also associated with any other stimulus presented during this learning procedure, which causes that when the cue is presented, the subject activates a memory not only of the consequence but also of all other stimuli that were present during training. This memory in turn also indirectly activates a memory of the consequence. ...
... A similar concern over whether passing summation and retardation tests is sufficient to demonstrate conditioned inhibition was raised by Miller and Matzel (1988). These authors noted that the attentional shifts, which the joint application of the summation and retardation tests is supposed to rule out, may not be mutually exclusive. ...
... The rationale underlying the two-test rule (Rescorla, 1969b) is that retarded acquisition of the CR could arise from decreased attention to the target CS and that the summation effect could arise from enhanced attention to the target CS; thus, the passage of both tests indicates conditioned inhibition because attention to the target CS cannot be decreased and enhanced at the same time. Nevertheless, Miller and Matzel (1988) argued that the attentional variables that might impact tests for conditioned inhibition could reflect dissociable and therefore independent pro-cesses. The attention-like process that could affect the rate of learning in retardation tests may be related to a decrease in the associability of the target CS. ...
... It seems hard to conceive that an operation could be effective in reducing the attention toward a stimulus sufficiently to cause a detectable retardation effect, and at the same time draw enough attention to attenuate the CR evoked by the transfer CS in summation trials. However, although under Rescorla's (1969b) rationale this outcome is not likely, under Miller and Matzel's (1988) view (see the subsection on problems with tests for conditioned inhibition) it is quite possible. ...
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©American Psychological Association, 2019. This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. The final article is available, upon publication, at: http://dx.doi.org/10.1037/xan0000193
... This is problematic at a theoretical level, because most models aimed at explaining human cognition have appealed to simple principles derived from basic learning theories (Mackintosh, 1975;Pearce & Hall, 1980;Rescorla & Wagner, 1972;Wagner, 1981), which were originally designed to account for cue competition phenomena. While the aforementioned models explain competition as a deficit in acquisition, some have proposed that competition results from a deficit in retrieval of the target information (Miller & Matzel, 1988;Stout & Miller, 2007). Other models have used these relatively simple rules in more complex architectures (Gluck & Bower, 1988;Kruschke, 2001;McClelland & Rumelhart, 1985) and real-time instantiations such as reinforcement learning (Sutton & Barto, 1981, 1990, all of which have had a profound influence on research programs aimed at understanding the neural basis of learning (Niv et al., 2015;Niv & Schoenbaum, 2008;Schultz et al., 1997). ...
... As it was mentioned in the introduction, classic associative theories can account for cue competition phenomena (Mackintosh, 1975;Miller & Matzel, 1988;Pearce & Hall,1980;Rescorla & Wagner,1972;Stout & Miller, 2007;Wagner, 1981), which is not surprising given that these theories were developed at the zeitgeist of cue competition. However, these models do not predict the absence of cue competition with weak contiguity across all the parametric variations that we have tested here. ...
... Traditionally, most learning theories have assumed that when multiple stimuli are presented together during training, they are processed in an elemental manner and compete during training (Mackintosh,1975;Pearce & Hall,1980;Rescorla & Wagner,1972;Wagner, 1981) or at the time of test during retrieval (Miller & Matzel, 1988;Stout & Miller, 2007). However, some theories TEMPORAL AND SPATIAL CONTIGUITY have proposed that stimuli are processed in a configural fashion (Pearce, 1987(Pearce, , 1994(Pearce, , 2002; also see Cheng, 2008, for a discussion of the potential of configural processes to account for findings in the spatial domain). ...
Article
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Over the last 50 years, cue competition phenomena have shaped theoretical developments in animal and human learning. However, recent failures to observe competition effects in standard conditioning procedures, as well as the lengthy and ongoing debate surrounding cue competition in the spatial learning literature, have cast doubts on the generality of these phenomena. In the present study, we manipulated temporal contiguity between simultaneously trained predictors and outcomes (Experiments 1-4), and spatial contiguity between landmarks and goals in spatial learning (Supplemental Experiments 1 and 2; Experiment 5). Across different parametric variations, we observed overshadowing when temporal and spatial contiguity were strong, but no overshadowing when contiguity was weak. Thus, across temporal and spatial domains, we observed that contiguity is necessary for competition to occur, and that competition between cues presented simultaneously during learning is absent when these cues were either spatially or temporally discontiguous from the outcome. Consequently, we advance a model in which the contiguity between events is accounted for and which explains these results and reconciles the previously contradictory findings observed in spatial learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
... It can be stated that Rescorla-Wagner model focuses on US processing whereas attentional models focus more on CS processing. Another notable theory is the comparator hypothesis (Miller and Matzel, 1988), which accounts for blocking by competition between CSs during the memory retrieval process. Remarkably, although efforts have been directed to experimentally test these different theories, which of the theories mentioned best accounts for computational rules governing Pavlovian conditioning remains unclear in any conditioning system (Miller et al., 1995;Pearce, 2008;Mazur, 2013). ...
... As already mentioned, the most influential models to account for blocking are the Rescorla-Wagner model (Rescorla and Wagner, 1972), the attentional theories proposed by Mackintosh (1975) and by Pearce and Hall (1980), and the retrieval theory (or comparator hypothesis) proposed by Miller and Matzel (1988). However, whether blocking is better accounted for by any of the mentioned models has not been tested in an invertebrate species, except that Smith (1997) examined blocking in honey bees and argued that the Rescorla-Wagner model can at least in part account for blocking but the attentional theories seem not to account for it. ...
... Another question to be addressed in the future is to what extent the Pavlovian conditioning system with the errorcorrection rule is ubiquitous among invertebrates. The blocking phenomenon, a hallmark for the existence of the error-correction learning rule, has so far been reported only in slugs (Sahley et al., 1981), snails (Acebes et al., 2009;Prados et al., 2013a), and planarians (Prados et al., 2013b) but whether it occurs by errorcorrection learning or by other process, such as cue competition during memory retrieval (Miller and Matzel, 1988) or simple selective attentional process not coupled to error-correction learning (see Terao et al., 2015) has not been investigated. Slugs and snails possess well-developed central nervous systems (Sahley et al., 1981;Loy et al., 2006), comparable to those of insects, and it would be therefore likely that the blocking effect is based on error-correction learning rules as well. ...
Article
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Elucidation of the conditions in which associative learning occurs is a critical issue in neuroscience and comparative psychology. In Pavlovian conditioning in mammals, it is thought that the discrepancy, or error, between the actual reward and the predicted reward determines whether learning occurs. This theory stems from the finding of Kamin’s blocking effect, in which after pairing of a stimulus with an unconditioned stimulus (US), conditioning of a second stimulus is blocked when the two stimuli are presented in compound and paired with the same US. Whether this theory is applicable to any species of invertebrates, however, has remained unknown. We first showed blocking and one-trial blocking of Pavlovian conditioning in the cricket Gryllus bimaculatus, which supported the Rescorla–Wagner model but not attentional theories, the major competitive error-correction learning theories to account for blocking. To match the prediction error theory, a neural circuit model was proposed, and prediction from the model was tested: the results were consistent with the Rescorla–Wagner model but not with the retrieval theory, another competitive theory to account for blocking. The findings suggest that the Rescorla–Wagner model best accounts for Pavlovian conditioning in crickets and that the basic computation rule underlying Pavlovian conditioning in crickets is the same to those suggested in mammals. Moreover, results of pharmacological studies in crickets suggested that octopamine and dopamine mediate prediction error signals in appetitive and aversive conditioning, respectively. This was in contrast to the notion that dopamine mediates appetitive prediction error signals in mammals. The functional significance and evolutionary implications of these findings are discussed.
... According to this model, stimulus preexposure reduces the stimulus novelty, which is responsible not only for slower stimulus-reinforcement acquisition, but also for slower retrieval during the testing phase. This model can accommodate a large body of existing evidence on latent inhibition, although it cannot account for evidence suggesting that disruption of latent inhibition is due to retrieval, rather than acquisition impairments (Weiner, Lubow, & Feldon, 1984;Miller & Matzel, 1988 ...
... These interfering formations could be either 'stimulus-context' (Miller & Matzel, 1988;Wagner, 1981) or 'stimulus-no event' associations (Reed, 1995;Reed & Tsakanikos, 2002). Similarly, from a cognitive perspective (Hemsley, 1993), latent inhibition has been explained as the result of contextual information ('the CSre does not predict a significant event'), which interferes later on with the acquisition of new information about the CSre-According to the associative view, schizophrenic patients fail to retain (or to retrieve) past associations from the pre-exposure phase. ...
... although it was found restored for the highschizotypy scorers, a finding that can be predicted by the attentional view of latent inhibition deficits. However, this reversal may also suggest that disruption of this phenomenon in schizophrenia might not be due to a failure of acquisition, but due to a failure of expression of latent inhibition (see . Miller & Matzel, 1988). Correspondingly, it has been shown that administration of damphetamine abolishes the expression, but not the acquisition of latent inhibition (Weiner etal., 1984), while haloperidol facilitates the expression, but not the acquisition of latent inhibition (Weiner etal., 1987). Paradoxically, if is accepted that the current data lent add ...
Thesis
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The thesis adopted a personality-based approach to experimental psychopathology testing alternative interpretations of latent inhibition deficits as a function of psychotic-like features in non-clinical participants. Chapter 1 reviews the evidence on the continuity of psychotic-like experiences, describes the historical origins of dimensional views of psychosis, and discusses methodological advantages and pitfalls in schizotypy research. Chapter 2 reviews different sources of evidence on a link between disruption of latent inhibition and the schizophrenia continuum, as well different theories of latent inhibition, and discusses methodological issues in terms of the existing latent inhibition paradigms. The review suggests that the interpretation of the disruption of latent inhibition within the schizophrenia continuum remains elusive due to a number of methodological and theoretical problems. In Chapter 3, a preliminary evaluation of self-report psychotic-like experiences was examined in terms of the capacity of different psychometric scales to predict perceptual and decision biases, akin to those observed in schizophrenia, when searching for fast moving words. Additionally, this chapter examined whether various schizotypy traits were associated with the ability to identify fast moving words, prior to the development of this paradigm as a latent inhibition procedure (Experiments 1 & 2). In Chapter 4, a novel latent inhibition paradigm was introduced. Visual search of fast moving words was examined as a function of target preexposure, amount of pre-exposure, and schizotypy (STA), without the target/ distractor reversal employed in most past investigations of latent inhibition in humans, and without including a masking task (Experiment 3 & 4). Latent inhibition was found to be relatively disrupted in high-schizotypy scores, but intact in their low-schizotypy counterparts. In Chapter 5, latent inhibition was examined in relation to schizotypy after procedural changes were introduced to address possible confounds in the previous experiments. In addition, in effort to evaluate attentional accounts, performance after stimulus preexposure was examined under individual testing (Experiment 5) and group testing (Experiment 6) conditions. In Chapter 6, in order to evaluate context effects on latent inhibition, and test predictions derived from opposing accounts, latent inhibition was assessed in high- and low-schizotypy scorers within a stable context (Experiment 7), and after a context change (Experiment 8). In Chapter 7, in order to evaluate whether the latent inhibition deficits are due to enhanced stimulus salience (related to a putative heightened perceptual awareness in high-schizotypy scorers), participants were conjointly tested in terms of latent inhibition and their ability to discriminate between different levels of stimulus salience, as assessed by a visual pop-out task (Experiments 9 & 10). In Chapter 8, a compound-stimulus discrimination paradigm was developed (Experiment 11), in order to test target/distractor shift-learning in different schizotypy dimensions (Experiment 12). In Chapter 9, a theoretical integration of the findings is proposed. The data obtained are discussed in terms of a two-component (attentional + associative) model of latent inhibition deficits.
... Many experiments have shown that humans (Baker, Mercier, Vallée-Tourangeau, Frank, & Pan, 1993;Shanks & Dickinson, 1987;Wasserman, 1990) and animals (Miller & Matzel, 1988;Rescorla, 1968) can detect contingency accurately and are sensitive to variations in contingency. This is true both when the cue and the outcome are external to the organism (i.e., Cue A predicts or causes Outcome B) as well as when the cue is the participants' behavior (e.g., Action A causes Outcome B). ...
... This is true both when the cue and the outcome are external to the organism (i.e., Cue A predicts or causes Outcome B) as well as when the cue is the participants' behavior (e.g., Action A causes Outcome B). As a consequence, animal conditioning is usually impaired when a noncontingent cue, which signals both the presence and the absence of the outcome with the same probability, is used (Miller & Matzel, 1988;Rescorla, 1968). Likewise, experiments with humans have shown that attention becomes impaired in response to stimuli that are inconsistent signals of the outcome (Beesley & Le Pelley, 2011;Cobos, Vadillo, Luque, & Le Pelley, 2018;Le Pelley, Mitchell, Beesley, George, & Wills, 2016). ...
... Another very clear prediction of associative models is that when there are two or more cues that are potentially associated to the same outcome, the cues will compete for association with the outcome. If one of the cues acquires strong associative strength, then responding to the other cue will be impaired (e.g., Mackintosh, 1975;Miller & Matzel, 1988;Pearce & Hall, 1980;Rescorla & Wagner, 1972). These cue competition effects have been observed in many animal conditioning experiments (e.g., Esmorís-Arranz, Miller, & Matute, 1997;Kamin, 1968) as well as in many human experiments (e.g., Baker et al., 1993;Beesley & Le Pelley, 2011;Morís, Cobos, Luque, & López, 2014;Shanks & Dickinson, 1987;. ...
Article
Many experiments have shown that humans and other animals can detect contingency between events accurately. This learning is used to make predictions and to infer causal relationships, both of which are critical for survival. Under certain conditions, however, people tend to overestimate a null contingency. We argue that a successful theory of contingency learning should explain both results. The main purpose of the present review is to assess whether cue-outcome associations might provide the common underlying mechanism that would allow us to explain both accurate and biased contingency learning. In addition, we discuss whether associations can also account for causal learning. After providing a brief description on both accurate and biased contingency judgments, we elaborate on the main predictions of associative models and describe some supporting evidence. Then, we discuss a number of findings in the literature that, although conducted with a different purpose and in different areas of research, can also be regarded as supportive of the associative framework. Finally, we discuss some problems with the associative view and discuss some alternative proposals as well as some of the areas of current debate. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
... The first used simulations to show that a theory, such as Rescorla-Wagner, which just relies on a common error term, can explain the compound test data if the function that translates learning into performance is double-sigmoidal across the full range of associative strength (i.e., from inhibition through to excitation). The second part likewise used simulations to show that a theory, such as the comparator theory (Miller & Matzel, 1988), which does not invoke a common error term, can also explain the compound test data. Thus, a common error term is sufficient to explain the compound test data, but it is not necessary. ...
... The second challenges the claim that a common error term is not sufficient to explain the associative changes that occur during compound conditioning by demonstrating that this error term, when combined with a nonlinear (sigmoid) mapping function, can explain the compound test results. The third challenges the claim that a common error term is necessary to explain associative changes in compound conditioning by showing how a theory that does not invoke a common error term can also explain the compound test results (e.g., Miller & Matzel, 1988;Stout & Miller, 2007). The overall goal of the article is to show that, contrary to suggestions by Rescorla and others, inferences based on applications of the compound test procedure remain dependent on how learning maps onto performance. ...
... However, other theories, ones that do not rely on error-correction mechanisms, also explain these phenomena. One such theory is the comparator model developed by Miller and colleagues (Miller & Matzel, 1988;Stout & Miller, 2007). According to this theory, the strength of an association increases with CS-US pairings and decreases with CS alone exposures. ...
Article
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Rescorla (2000) devised the compound test procedure as a means of comparing changes in associative strength when cues with different training histories are conditioned in compound. It was specifically intended to dissociate changes in learning from changes in performance, and thereby, permit inferences about learning independently of assumptions regarding how learning translates into performance. In an elegant series of studies, Rescorla (2000, 2001) used this procedure to show that cues conditioned in compound undergo unequal associative change such that the poorer predictor of the outcome undergoes greater change rather than the equal change predicted by theories (e.g., Rescorla & Wagner, 1972) that rely on a common error term. Rescorla explained the data from the compound test procedure by proposing that associative change is calculated using a combination of two error terms, a common error term that carries the predictions of all cues present on a trial and an individual term that carries the prediction of any cue in isolation. This article is in two parts. The first used simulations to show that a theory, such as Rescorla-Wagner, which just relies on a common error term, can explain the compound test data if the function that translates learning into performance is double-sigmoidal across the full range of associative strength (i.e., from inhibition through to excitation). The second part likewise used simulations to show that a theory, such as the comparator theory (Miller & Matzel, 1988), which does not invoke a common error term, can also explain the compound test data. Thus, a common error term is sufficient to explain the compound test data, but it is not necessary. (PsycINFO Database Record
... In contrast, several learning theories suggest that context cues can influence evaluations by acquiring direct context-evaluation associations (Miller & Matzel, 1988;Rescorla & Wagner, 1972). In this case, the context cues become directly associated with evaluations rather than setting the occasion for the activation of different target cue-evaluation associations. ...
... Although most work on contextualised attitude change has viewed retrieval cues as modulatory cues, there are several demonstrations in the learning literature of retrieval cues exerting a more direct influence on conditioned responding (for a review, see Urcelay & Miller, 2014). In contrast to retrieval theories, many theories of associative learning view the context as an additional, discrete cue that competes or summates with other cues (Miller & Matzel, 1988;Rescorla & Wagner, 1972). For instance, these models argue that presentations of the unconditioned stimulus (US) alone in a conditioned chamber can produce context-US associations (i.e. ...
Article
Initial evaluations generalise to new contexts, whereas counter-attitudinal evaluations are context-specific. Counter-attitudinal information may not change evaluations in new contexts because perceivers fail to retrieve counter-attitudinal cue-evaluation associations from memory outside the counter-attitudinal learning context. The current work examines whether an additional, counter-attitudinal retrieval cue can enhance the generalizability of counter-attitudinal evaluations. In four experiments, participants learned positive information about a target person, Bob, in one context, and then learned negative information about Bob in a different context. While learning the negative information, participants wore a wristband as a retrieval cue for counter-attitudinal Bob-negative associations. Participants then made speeded as well as deliberate evaluations of Bob while wearing or not wearing the wristband. Internal meta-analysis failed to find a reliable effect of the counter-attitudinal retrieval cue on speeded or deliberate evaluations, whereas the context cues influenced speeded and deliberate evaluations. Counter to predictions, counter-attitudinal retrieval cues did not disrupt the generalisation of first-learned evaluations or the context-specificity of second-learned evaluations (Experiments 2–4), but the counter-attitudinal retrieval cue did influence evaluations in the absence of context cues (Experiment 1). The current work provides initial evidence that additional counter-attitudinal retrieval cues fail to disrupt the renewal and generalizability of first-learned evaluations.
... Most of the theoretical proposals published over the following decades incorporated this principle in one way or another (Mackintosh, 1975;Rescorla and Wagner, 1972;Wagner, 1981). The only noticeable exception to this general trend is the Comparator Hypothesis (Miller and Matzel, 1988), which assumes that learning is driven by mere contiguity (i.e., by CS-US pairings) and that sensitivity to other factors like predictive value is related to additional processes that have little to do with learning. ...
... Since the publication of the seminal chapter outlining the main features of the Comparator Hypothesis, Ralph Miller and colleagues have published several developments of the theory (Denniston et al., 2001;Miller and Matzel, 1988;Stout and Miller, 2007). Only the latest of these extensions contains a comprehensive and fully developed mathematical formulation, which, for our present purposes, is unnecessarily complicated. ...
Article
Full-text available
Our ability to detect statistical dependencies between different events in the environment is strongly biased by the number of coincidences between them. Even when there is no true covariation between a cue and an outcome, if the marginal probability of either of them is high, people tend to perceive some degree of statistical contingency between both events. The present paper explores the ability of the Comparator Hypothesis to explain the general pattern of results observed in this literature. Our simulations show that this model can account for the biasing effects of the marginal probabilities of cues and outcomes. Furthermore, the overall fit of the Comparator Hypothesis to a sample of experimental conditions from previous studies is comparable to that of the popular Rescorla-Wagner model. These results should encourage researchers to further explore and put to the test the predictions of the Comparator Hypothesis in the domain of biased contingency detection.
... Most of the theoretical proposals published over the following decades incorporated this principle in one way or another (Mackintosh, 1975;Rescorla and Wagner, 1972;Wagner, 1981). The only noticeable exception to this general trend is the Comparator Hypothesis (Miller and Matzel, 1988), which assumes that learning is driven by mere contiguity (i.e., by CS-US pairings) and that sensitivity to other factors like predictive value is related to additional processes that have little to do with learning. ...
... Since the publication of the seminal chapter outlining the main features of the Comparator Hypothesis, Ralph Miller and colleagues have published several developments of the theory (Denniston et al., 2001;Miller and Matzel, 1988;Stout and Miller, 2007). Only the latest of these extensions contains a comprehensive and fully developed mathematical formulation, which, for our present purposes, is unnecessarily complicated. ...
Preprint
Our ability to detect statistical dependencies between different events in the environment is strongly biased by the number of coincidences between them. Even when there is no true covariation between a cue and an outcome, if the marginal probability of either of them is high, people tend to perceive some degree of statistical contingency between both events. The present paper explores the ability of the Comparator Hypothesis to explain the general pattern of results observed in this literature. Our simulations show that this model can account for the biasing effects of the marginal probabilities of cues and outcomes. Furthermore, the overall fit of the Comparator Hypothesis to a sample of experimental conditions from previous studies is comparable to that of the popular Rescorla-Wagner model. These results should encourage researchers to further explore and put to the test the predictions of the Comparator Hypothesis in the domain of biased contingency detection.
... Judgement of the strength of the relationship between two events, E1 and E2, is enhanced by the conjoint presence or conjoint absence of the two events, and is diminished to the extent that either of the events is experienced alone (Allan & Jenkins, 1983; Vallee-Tourangeau, Murphy, Drew & Baker, 1998a, 1998bWasserman, Dorner & Kao, 1990). In this sense, judgements of association reflect a sensitivity to the empirical correlation between the two events (Baker, Murphy & Vallee-Tourangeau, 1996;DeHouwer & Beckers, 2002;Miller & Matzel, 1988;White, 2004). ...
... Descriptive theories of learning have generated algorithms for predicting performance from paired event learning, specifically identifying how the four type of trials (i.e., both events present, both absent, one present with the other absent, and the other present with the first absent) might be combined and the relative importance of these different experiences (Cheng, 1997;Hallam, Grahame, & Miller, 1992;Kao & Wasserman, 1993;Kelley, 1973;Miller & Matzel, 1988;Rescorla, 1968;White, 2004). In general, these accounts assume that learning is frequentist and that although increased duration of exposure might enhance coding, it would not be perceived as multiple instances. ...
Article
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The strength of the learned relation between two events, a model for causal perception, has been found to depend on their overall statistical relation, and might be expected to be related to both training trial frequency and trial duration. We report five experiments using a rapid-trial streaming procedure containing Event 1-Event 2 pairings (A trials), Event 1-alone (B trials), Event 2-alone (C trials), and neither event (D trials), in which trial frequencies and durations were independently varied. Judgements of association increased with increasing frequencies of A trials and decreased with increasing frequencies of both B and C trials but showed little effect of frequency of D trials. Across five experiments, a weak but often significant effect of trial duration was also detected, which was always in the same direction as trial frequency. Thus, both frequency and duration of trials influenced learning, but frequency had decidedly stronger effects. Importantly, the benefit of more trials greatly outweighed the observed reduction in effect size caused by a proportional decrease in trial duration. In experiment 5, more trials of proportionately shorter duration enhanced effects on contingency judgments despite a shortening of the training session. We consider the observed 'frequency advantage' with respect to both frequentist models of learning and models based on information. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
... En un estudio relativamente reciente en el que se utilizaron ratas como sujetos experimentales, Lattal (1999) demostró que el condicionamiento de las respuestas de asomarse al dispensador de alimento igualmente puede predecirse por la razón I/T, siempre que las respuestas durante la señal se dividan entre la suma de dichas respuestas y aquellas que tienen lugar durante un período equivalente, previo a la presentación de la señal (i.e., razón de elevación). Independientemente de la interpretación conceptual que pueda ofrecerse, el hecho de que la ejecución durante el período previo a la presentación de la señal determine la aplicabilidad de la razón I/T a las respuestas de asomarse al dispensador de alimento, demuestra que los cambios en el responder durante los estímulos condicionales no son independientes de las respuestas que ocurren durante el intervalo entre ensayos; tal como lo sugieren la mayoría de los modelos más influyentes sobre el condicionamiento clásico (Gibbon & Balsam, 1981;Gallistel & Gibbon, 2000;Miller & Matzel, 1988;Rescorla & Wagner, 1972;Wagner, 1981). El presente estudio exploró dicha posibilidad, igualmente sobre las respuestas de asomarse al dispensador, utilizando diferentes intervalos entre estímulos motivacionalmente relevantes. ...
... La mayoría de los modelos actuales del condicionamiento clásico suponen que bajo arreglos contingenciales por el estilo, las correlaciones entre los estímulos condicional e incondicional producen cambios en el responder del organismo no sólo en presencia del primero, sino igualmente durante el intervalo entre ensayos. En general, en todos los casos se asume que el grado de condicionamiento que puede ganar el estímulo condicional depende del grado de condicionamiento ganado por el intervalo entre ensayos o contexto (Gibbon & Balsam, 1981;Gallistel & Gibbon, 2000;Miller & Matzel, 1988;Rescorla & Wagner, 1972;Wagner, 1981). En este sentido, destaca que en el presente estudio la proporción de tiempo de asomarse al dispensador durante dicho intervalo haya sido menor mientras mayor fue la proporción de tiempo de asomarse al dispensador en presencia del agua. ...
... During the first phase, an association forms between the target stimulus and some form of response or responses that accompany the sensory habituation. This interferes with retrieval of an association between the target stimulus and the new response acquired during Phase 2. Subsequent retrieval-focused accounts have proposed that the LI effect occurs because the acquisition of an association between the target stimulus and no outcome during Phase 1 interferes with the retrieval of the association between the target stimulus and outcome acquired in Phase 2 (Bouton, 1993;Miller & Matzel, 1988;Miller & Schachtman, 1985). Such interference accounts suggest that retarded performance can be observed despite intact learning (e.g., Bouton, 1993). ...
... Evidence supporting the interference account also suggests that LI may be context dependent, with changes in physical or temporal context between the two learning phases reducing the interference effect. For instance, the comparator hypothesis, assumes that the association formed between the stimulus and the context during Phase 1 interferes with the expression of the stimulus-outcome association in Phase 2 (Escobar, Oberling, & Miller, 2002;Miller & Matzel, 1988;Oberling, Gosselin, & Miller, 1999). A similar assumption, of context dependence, is inherent to Wagner's (1981) standard operating procedures (SOP). ...
Article
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Latent inhibition (LI) is a startlingly simple effect in which preexposure of a stimulus without consequence retards subsequent responding to a stimulus–consequence relation. The effect was first demonstrated with Pavlovian conditioning in animals and was later suggested to be a marker of human psychopathology such as schizophrenia. Individual differences in LI has supported the continued use of animal models to understand human mental health. In this review, we ask whether there is sufficient evidence to support the continued application of LI from animal models to human psychopathology because of the weak evidence for LI in humans. There is considerable variability in the methods used to assess LI, sustaining different theoretical accounts of the effects observed, which differ from the accepted accounts of LI as demonstrated in animals. The review shows that although there have been many experiments testing human LI, none provide the necessary experimental controls to support the conclusion that retarded responding is caused simply by preexposure to a stimulus, as has been demonstrated with animal models. Establishing this conflict, we set out a framework for future research.
... Disorders of emotional memory, such as posttraumatic stress disorder and anxiety disorders, are typically characterized by associative fear memories (Ehlers & Clark, 2000;Foa & Kozak, 1986). In order to reduce fear responses, traditional psychological treatments mainly rely on exposure techniques, which are thought to impede the activation of dysfunctional fear memories via inhibitory learning processes (Bouton, 1993;Miller & Matzel, 1988). Recently, imagery rescripting (IR) has been introduced as a means to change emotional memories (e.g., Holmes, Arntz, & Smucker, 2007;Smucker, Dancu, Foa, & Niederee, 1995). ...
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Imagery rescripting is a promising treatment for a variety of disorders, but its working mechanisms remain largely unknown. To elucidate the associative and evaluative learning processes underlying imagery rescripting, we exposed participants to an aversive film clip followed by an instructed fear-conditioning procedure. The acquired fear memory was subsequently manipulated by either rescripting- (IR) or exposure-based (IE) interventions and their effects were examined on subjective and psychophysiological fear responses in three successive studies. Though the interpretation of the results was challenged with respect to the employed analogue IR intervention (Exp 1) and unexpected findings in the control condition (Exp 3), the present results establish preliminary evidence for the hypothesis that IR produces differential effects on fear responding when compared to IE. For example, in line with stimulus devaluation theory, IR effectively reduced subjective distress to the conditioned stimulus (Exp 2). Also, IR resulted in decreased physiological fear responses after fear reinstatement (Exp 3). The findings advance our general understanding of the processes involved in IR and they tentatively indicate that rescripting- and exposure-based treatments may work through different mechanisms. Moreover, this line of research demonstrates the challenges encountered when working with analogue models to test mechanisms of therapeutic change.
... Other theories have placed less emphasis on what happens during learning, and instead suggested that the retrieval of information is the critical moment at which cue competition occurs. For example, the Comparator Hypothesis (CH; Miller and Matzel, 1988) assumes that there is no competition during training, but rather competition occurs at the time of retrieval. According to this view, learning proceeds for each stimulus independently of whether there are other stimuli presented on a given trial. ...
Chapter
In this chapter, we first introduce classical conditioning from a historical perspective. We then characterize what is learned during classical conditioning, and do so while noting some practical and functional implications of classical conditioning. In the second part, we provide a succinct overview of phenomena such as cue competition and interference, which have received attention in the laboratory. We also describe major theoretical ideas that have been proposed to account for these phenomena. While there is a long was to go in achieving a better understanding of classical conditioning, research conducted in the last century has certainly paved the way for a better understanding of learning in humans and other animals.
... Another model which includes a single error-term and an additional process to explain cue competition effects is the comparator hypothesis (Denniston, Savastano, & Miller, 2001;Miller & Matzel, 1988;Stout & Miller, 2007). This theory proposes that the strength of the association between a cue and the outcome is based on single error-term rules. ...
Article
Rescorla and Wagner’s model of learning describes excitation and inhibition as symmetrical opposites. However, tasks used in human causal learning experiments, such as the allergist task, generally involve learning about cues leading to the presence or absence of the outcome, which may not reflect this assumption. This is important when considering learning effects which provide a challenge to this model, such as the redundancy effect. The redundancy effect describes higher causal ratings for the blocked cue X than for the uncorrelated cue Y in the design A+/AX+/BY+/CY-, the opposite pattern to that predicted by the Rescorla-Wagner model, which predicts higher associative strength for Y than for X. Crucially, this prediction depends on cue C gaining some inhibitory associative strength. In this manuscript, we used a task in which cues could have independent inhibitory effects on the outcome, to investigate whether a lack of inhibition was related to the redundancy effect. In Experiment 1, inhibition for C was not detected in the allergist task, supporting this possibility. Three further experiments using the alternative task showed that a lack of inhibition was related to the redundancy effect: the redundancy effect was smaller when C was rated as inhibitory. Individual variation in the strength of inhibition for C also determined the size of the redundancy effect. Given that weak inhibition was detected in the alternative scenario but not in the allergist task, we recommend carefully choosing the type of task used to investigate associative learning phenomena, as it may influence results.
... Causal models, which seek to explain the process by which people make inferences about causality between two events on the basis of their temporal relationship, are better able to accommodate the findings in Chapter 5. Causal reasoning has also been demonstrated in animals; for example, Sawa (2009) found that rats are able to generalise causal cues for food rewards. Causal models do not face the same problem as associative models when explaining the experimental findings of Chapter 5 because they make a distinction between learning and performance (see: Allan, Siegel & Tangen, 2005;Miller & Matzel, 1998). Moreover, causal models do not specify that organisms use only a single measure of the relationship (e.g. ...
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Over the last forty years, experimental support for different models of associative learning has come from a range of phenomena. Support for the Rescorla-Wagner (1972) model comes from blocking and overshadowing experiments; however, this model is unable to explain the findings of latent inhibition experiments. The Mackintosh (1975) model, on the other hand, is able to accommodate the findings from blocking, overshadowing and latent inhibition experiments, as well as discrimination learning, relative validity, learned irrelevance, intra-/extra-dimensional shift (IDS/EDS) and learned predictiveness experiments. The model proposed by Pearce and Hall (1980) is also able to explain the findings of blocking, overshadowing and latent inhibition experiments, but in addition to this it is also able to accommodate the effects of partial reinforcement and negative transfer. In an attempt to unify the theories into a single model that is able to explain all the aforementioned phenomena, Le Pelley (2004) proposed a hybrid model of associative learning, but it was not easily able to incorporate the effects of learned value. Alternatively, Esber and Haselgrove (2011) proposed a model that reconciles the influence of predictiveness and uncertainty into a single mechanism for attentional allocation, and this model was better able to explain the experimental findings of learned value. Theories of associative learning claim that a cue’s predictive validity determines the amount of attention it attracts and to what extent it is subsequently learned about (e.g. Mackintosh, 1975; Pearce & Hall, 1980). In Chapter 2, using eye-tracking methodology during a learned predictiveness task, several measures of overt attention were recorded and compared on trials where the predictive contingency was certain or less certain. Findings revealed that, at a within-trial level, good predictors of an outcome attracted more attention compared to irrelevant cues. Although, at a between-trial level, uncertain trials attracted more attention compared to certain trials. These findings provide support for the conflicting attentional modulation predictions made by the Mackintosh (1975) and Pearce-Hall (1980) models. Consequently, these findings can only be fully explained by appealing to a model of associative learning that incorporates both the principles of predictiveness and uncertainty (e.g. Le Pelley, 2004; Esber & Haselgrove, 2011). Prior to eye-tracking becoming more widely available as a measure of overt visual attention, stimulus associability was used as an indirect measure of attention since it is assumed that the speed at which a stimulus is learned about reflects the amount of attention it attracts. This is demonstrated in the IDS/EDS task which consistently finds that IDS are easier than EDS because in the IDS condition the higher associability of the predictive dimension in Stage 1 facilitates learning when generalised into Stage 2. Until now, eye gaze during an IDS/EDS task has not been investigated to determine whether the effect results from a shift in overt attention from Stage 1 into Stage 2. Chapter 3 revealed that participants acquired an attentional bias towards predictive cues in Stage 1 which transferred into Stage 2; however, in the EDS condition this bias was maintained only very briefly. Eye-tracking during learned predictiveness tasks using adult participants has revealed that cues which are good predictors of an outcome attract more overt visual attention than cues which are irrelevant. However, thus far, little research has investigated whether good predictors of reinforcement and non-reinforcement show a comparable effect. Moreover, it is currently unclear whether children and non-human animals demonstrate the learned predictiveness effect. Chapter 4 employed the same design and stimuli to examine eye gaze towards cues during a simple learned predictiveness task (AX+, AY+, BX-, BY-) in adults, children and an orangutan. Results revealed that all participants demonstrated the learned predictiveness effect, directing more attention towards cues that were good predictors of the outcome compared with cues that were irrelevant. However, for adult humans this effect was only present on reinforced trials and questionnaire data suggested they had only learned about one of the predictive contingencies. Contemporary discussions of associative learning have emphasised the importance of a cue’s predictive relevance in determining learned variations in attention. However, most theoretical accounts of the effect do not capture the notion of prediction – only associative strength, or relative associative strength (e.g. Mackintosh, 1975). In Chapter 5, letters were established as congruent or incongruent cues of other letters presented simultaneously or serially with a target cue. Results revealed no difference in the amount of attention directed towards congruent and incongruent cues if stimuli were presented simultaneously or serially when participants were required to respond to the identity of the target cue. However, an attentional bias towards congruent cues compared to incongruent cues was found when cues were presented serially, if participants were permitted to predict the identity of the target before its onset.
... However, Craske andcolleagues (2008, 2014) found that habituation within sessions and between sessions does not always seem to be the best predictor of treatment outcome and success. Therefore, it has been argued that inhibitory learning-instead of "corrective" learning-is central to extinction of fear, and thus to exposure (Bouton, 1993;Craske et al., 2008Craske et al., , 2014Miller & Matzel, 1988). In this inhibitory learning model, disconfirming expectancies regarding the likelihood of the occurrence of the aversive event(s) (US) are believed to be essential to the therapeutic outcome (Craske et al., 2014). ...
Article
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The benefits of exposure-based interventions for anxiety disorders are substantial but not stable for everyone, given that these interventions are often followed by relapse of symptoms. A body of research provides a background on how to add certain strategies in exposure-based therapy to prevent relapse in anxiety disorders. This review summarizes some of these strategies and provides clear-cut clinical implications. Studies that provide support for two types of strategies to prevent relapse have been reviewed—the use of multiple contexts and the use of retrieval cues. The use of multiple contexts reduces context and stimulus specificity of extinction learning during exposure, while the use of retrieval cues enhances memory (re)consolidation and retrieval after exposure. The described strategies to enhance the accessibility and therefore the retrievability of exposure-based learning to prevent relapse in anxiety disorders can be summarized as advice to conduct exposure under variable conditions. This way, the generalizability of what is learned during exposure to the patients’ daily life after treatment improves. Therefore, adding these strategies in the course of exposure-based treatment of anxiety disorders seems beneficial. However, future replications and translational studies are needed to verify ecological validity.
... This observation appears potentially compatible with the view of performance-focused models. One formulation of the performance-focused models, the Comparator Hypothesis (Miller & Matzel, 1988), suggests that the association between the overshadowed CS and the US is acquired, but not expressed, in the presence of another stronger overshadowing CS (Denniston et al., 2003). When the overshadowing CS is removed, the overshadowed CS has a chance of being expressed. ...
Article
When people learn perceptual categories, if one feature makes it easy to determine the category membership, learning about other features can be reduced. In three experiments, we asked whether this cue competition effect could be fully eradicated with simple instructions. For this purpose, in a pilot experiment, we adapted a classical overshadowing paradigm into a human category learning task. Unlike previous reports, we demonstrate a robust cue competition effect with human learners. In Experiments 1 and 2, we created a new warning condition that aimed at eradicating the cue competition effect through top-down instructions. With a medium-size overshadowing effect, Experiment 1 shows a weak mitigation of the overshadowing effect. We replaced the stimuli in Experiment 2 to obtain a larger overshadowing effect and showed a larger warning effect. Nevertheless, the overshadowing effect could not be fully eradicated. These experiments suggest that cue competition effects can be a stubborn roadblock in human category learning. Theoretical and practical implications are discussed.
... Equation 1 provides one account of how learning about a single cue can be affected by the presence of other cues, but we have already shown it is challenged by the results of the experiments described thus far. Instead, we shall pursue the possibility of explaining these results with a theory that assumes changes in associative strength are governed by Equation 2. According to the comparator hypothesis (e.g., Miller & Matzel, 1988;Stout & Miller, 2007), all changes in associative strength are governed by this equation. A further assumption of the hypothesis is that associations will develop between two cues when they are presented together. ...
Article
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In four experiments, participants were shown a sequence of pairs of pictures of food and asked to predict whether each pair signalled an allergic reaction in a hypothetical patient. The pairs of pictures were used to present two simple discriminations that differed in their outcome ratio. A rich discrimination, 3AX+ BX−, involved three trials in which the compound of two foods, AX, was followed by a reaction, for every trial in which the compound BX was not followed by the outcome. A lean discrimination, CY+ 3DY− was based on the opposite outcome ratio. Upon the completion of this training, participants were asked to rate how likely an individual food would be followed by the allergic reaction. In each experiment, the rating for X was stronger than for Y. This outcome ratio effect poses a challenge for theories of learning that assume changes in associative strength are governed by a common error term, based on the significance of all the cues present on a trial. Instead, the results are consistent with the assumption that changes in associative strength are governed by an individual error term, based on the significance of a single cue.
... This is especially troublesome for studies that involve brain lesions or administration of drugs, in which the several usual control conditions (e.g., sham lesions, vehicle administration) would have to be multiplied by two while keeping a sufficient group size. In addition, a conceptual hindrance may emerge from the fact that each test is assumed to assess different independent underlying processes (Miller & Matzel, 1988). This may constitute a potential issue at the time of justifying whichever of the tests is being selected as a measure representing the construct of conditioned inhibition. ...
Article
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Impulsivity is an important construct in many different fields of behavioral science. A number of authors consider response inhibition deficit as an important part of impulsive behavior. Viewpoints range from those claiming that such an inhibitory deficit is a fundamental feature of all manifestations of impulsivity, to those that consider that it is just one of various independent components of impulsive behavior. In this article, we review some of the most common laboratory procedures used to evaluate response inhibition and their relation to impulsivity. We focus on one of these procedures, conditioned inhibition, which has fallen into neglect in the impulsivity literature. We consider three main reasons for this: (1) harsh critiques of the concept of inhibition by influential theorists, (2) difficulties with the control procedures needed to demonstrate conditioned inhibition, and (3) an apparent mismatching between conditioned-inhibition performance and typical definitions of response inhibition. We provide evidence and arguments that could help to overcome those critiques and methodological and conceptual barriers. We also note that the conditions assumed to induce conditioned inhibition are present in some other paradigms designed to measure impulsivity. If our assertions are correct, then studying conditioned inhibition as a learning process is of great importance for understanding impulsive behavior. Further research is needed to test how critical conditioned inhibition is to impulsivity.
... The RW model may be regarded as antiquated today. Context is not fully integrated into it and few learning preparations can be viewed as single-cue because learning does not occur in a vacuum (Miller and Matzel, 1988). Furthermore, the inability of the Rescorla-Wagner model to account for recovery from extinction and other phenomena is well-known (Miller et al., 1995). ...
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How stable and general is behavior once maximum learning is reached? To answer this question and understand post-acquisition behavior and its related individual differences, we propose a psychological principle that naturally extends associative models of Pavlovian conditioning to a dynamical oscillatory model where subjects have a greater memory capacity than usually postulated, but with greater forecast uncertainty. This results in a greater resistance to learning in the first few sessions followed by an over-optimal response peak and a sequence of progressively damped response oscillations. We detected the first peak and trough of the new learning curve in our data, but their dispersion was too large to also check the presence of oscillations with smaller amplitude. We ran an unusually long experiment with 32 rats over 3,960 trials, where we excluded habituation and other well-known phenomena as sources of variability in the subjects' performance. Using the data of this and another Pavlovian experiment by Harris et al. (2015), as an illustration of the principle we tested the theory against the basic associative single-cue Rescorla–Wagner (RW) model. We found evidence that the RW model is the best non-linear regression to data only for a minority of the subjects, while its dynamical extension can explain the almost totality of data with strong to very strong evidence. Finally, an analysis of short-scale fluctuations of individual responses showed that they are described by random white noise, in contrast with the colored-noise findings in human performance.
... What makes accounting for these phenomena particularly challenging is that they seem to depend upon an intrinsic assumption about fixed total probability such that a change in experienced probability associated with one CS or state can produce behaviors that suggest that subjects have adjusted related probabilities for CSs or states never themselves experienced under the new probabilities-that is, a change in probability associated with some CS seems to have been inferred strictly based on changes in the experienced probability associated with some other CS. Several models have been proposed to account for retrospective revaluation including (see Miller & Witnauer, 2016, for review): several iterations of Ralph Miller's own comparator hypothesis (Miller & Matzel, 1988;Miller & Witnauer, 2016), a modification of Rescorla-Wagner by Van Hamme and Wasserman (1994), a modification of Wagner's (1981) SOP model by Dickinson and Burke (1996), and a rehearsal-based model by Chapman (1991). In addition, Daw, Courville, and Dayan (2008) used a Kalman-filterbased model (Kalman, 1960) to account for backward unblocking, following on the original insight of Kakade and Dayan (2001). ...
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We describe a neurobiologically informed computational model of phasic dopamine signaling to account for a wide range of findings, including many considered inconsistent with the simple reward prediction error (RPE) formalism. The central feature of this PVLV framework is a distinction between a primary value (PV) system for anticipating primary rewards (Unconditioned Stimuli [USs]), and a learned value (LV) system for learning about stimuli associated with such rewards (CSs). The LV system represents the amygdala, which drives phasic bursting in midbrain dopamine areas, while the PV system represents the ventral striatum, which drives shunting inhibition of dopamine for expected USs (via direct inhibitory projections) and phasic pausing for expected USs (via the lateral habenula). Our model accounts for data supporting the separability of these systems, including individual differences in CS-based (sign-tracking) versus US-based learning (goal-tracking). Both systems use competing opponent-processing pathways representing evidence for and against specific USs, which can explain data dissociating the processes involved in acquisition versus extinction conditioning. Further, opponent processing proved critical in accounting for the full range of conditioned inhibition phenomena, and the closely related paradigm of second-order conditioning. Finally, we show how additional separable pathways representing aversive USs, largely mirroring those for appetitive USs, also have important differences from the positive valence case, allowing the model to account for several important phenomena in aversive conditioning. Overall, accounting for all of these phenomena strongly constrains the model, thus providing a well-validated framework for understanding phasic dopamine signaling. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
... The third family accounts for behavior indicative of CI without assuming the existence of inhibitory associations. An example of them is the comparator hypothesis (Miller and Matzel 1988). For this model, conditioned responding is the result of a process involving a comparison made in the moment of performance. ...
... One might argue that the development of a within-compound association between A and X would indeed reduce the expression of blocking, because at test X will activate the representation of A which in turn will activate a representation of the outcome, yielding strong conditioned responding despite a weak direct association between X and the outcome. However, in spite of this intuition, prominent formal theories of learning, like the comparator hypothesis (e.g., Miller & Matzel, 1988), actually make the opposite prediction that stronger within-compound associations would lead to stronger blocking. This is because a stronger A-X association is expected to produce a stronger downmodulation of responding to X by the indirect X-A and A-outcome links. ...
Article
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The blocking effect has inspired numerous associative learning theories and is widely cited in the literature. We recently reported a series of 15 experiments that failed to obtain a blocking effect in rodents. Based on those consistent failures, we claimed that there is a lack of insight into the boundary conditions for blocking. In his commentary, Soto (in press) argues that contemporary associative learning theory does provide a specific boundary condition for the occurrence of blocking, namely the use of same- versus different-modality stimuli. Given that in ten of our 15 experiments same-modality stimuli were used, he claims that our failure to observe a blocking effect is unsurprising. We cannot but disagree with that claim, because of theoretical, empirical, and statistical problems with his analysis. We also address two other possible reasons for a lack of blocking that are referred to in Soto’s (in press) analysis, related to generalization and salience, and dissect the potential importance of both. While Soto’s (in press) analyses raises a number of interesting points, we see more merit in an empirically guided analysis and call for empirical testing of boundary conditions on blocking.
... Another determinant that has often been implicatedeither explicitly or implicitlyin current generalization research relates to the notion that generalization comprises a decisionmaking process (Dunsmoor & Murphy, 2015;Dymond et al., 2015). Some associative theories indeed invoke separate performance mechanisms that only play a role at the time of testing (Boddez, Moors, Mertens, & De Houwer, 2020;Miller & Schachtman, 1988;Ralph R. Miller & Matzel, 1988). For example, it has been argued that conditioned responding is determined by a decision process that selects action tendencies that serve the goals of the organism (e.g., safety; for an elaborate discussion, see Boddez et al., 2020). ...
Article
The generalization of learned behavior has been extensively investigated, but accounting for variance in generalized responding remains a challenge. Based on recent advances, we demonstrate that the inclusion of perceptual measures in generalization research may lead to a better understanding of both intra- and interindividual differences in generalization. We explore various ways through which perceptual variability can influence generalized responding. We investigate its impact on the ability to discriminate between stimuli and how similarity between stimuli may be variable, rather than fixed, because of it. Subsequently, we argue that perceptual variations can yield different learning experiences and that interindividual differences in generalized responding may be understood from this perspective. Finally, we point to the role of memory and decision-making within this context. Throughout this paper, we argue that accounting for perception in current generalization protocols will improve the precision of obtained generalization gradients and the ability to infer latent mechanisms. This can inspire future attempts to use generalization gradients as a (clinical) predictor or to relate them to individual traits and neural correlates and, ultimately, may lead to new theoretical and clinical insights.
... In the context of EC, it has been argued that, unlike most other types of learned behavior, learned preferences depend on associations that reflect the number of stimulus co-occurrences but not events in which stimuli occur separately (see Baeyens, Eelen, Crombez, & Van den Bergh, 1992;Miller & Matzel, 1988). This idea could also account for the lack of extinction in our studies but only if it is assumed that activation can spread in a backward manner across these associations. ...
Article
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One of the most effective methods of influencing what people like and dislike is to expose them to systematic patterns (or ‘regularities’) in the environment, such as the repeated presentation of a single stimulus (mere exposure), two or more stimuli (evaluative conditioning) or to relationships between stimuli and behavior (approach/avoidance). Hughes, De Houwer, and Perugini (2016) found that evaluations also emerge when regularities in the environment intersect with one another. In this paper we examined if evaluations established via operant evaluative conditioning and intersecting regularities can be undermined via extinction or revised via counterconditioning. Across seven pre-registered studies (n = 1071) participants first completed a learning phase designed to establish novel evaluations followed by one of multiple forms of extinction or counterconditioning procedures designed to undo them. Results indicate that evaluations were - in general - resistant to extinction and counterconditioning. Theoretical and practical implications along with future directions are discussed.
... Since the mid-1980s, Miller's Comparator Hypothesis (cf. Miller and Matzel 1988) has been supported by hundreds of studies and has sparked novel research showing that responding can be modulated through training of the comparator stimuli (e.g., Blaisdell et al. 1999), with new theories being developed to explain these phenomena (for reviews, see Denniston et al. 2001;Stout and Miller 2007). The Comparator Hypothesis has undergone significant evolution since its first formulation, with an extended version, the development of which was prompted by the empirical discovery that overshadowing and latent inhibition treatments mutually counteract their response-attenuating effects other (Blaisdell et al. 1998), that incorporated rules for dealing with multiple comparator stimuli (ECH; Denniston et al. 2001), and a mathematical formalization of the ECH (Sometimes Competing Retrieval [SOCR]; Stout and Miller 2007). ...
Preprint
Biographical entry on Ralph R. Miller published in the Encyclopedia on Animal Cognition and Behavior.
... Given the intimate relationship 73 between credit assignment and decision making, it is essential to elucidate how credit is 74 apportioned among cues under various learning conditions. 75 Credit assignment is widely regarded as a competitive process in which the best 76 predictor of the outcome acquires substantial credit over the course of learning at the 77 expense of other predictors (e.g., Honey Pearce, 1994;Miller & Matzel, 1988;Wagner, 1981;Pearce & Hall, 1980;Mackintosh, 80 1975; Rescorla & Wagner, 1972). In support of this notion is evidence that cues compete 81 for credit in a range of tasks (Kamin, 1968;Pavlov, 1927, Wagner et al., 1968, Rescorla, 82 1968, 1970) and species, from C. elegans to humans (Merritt et Beauchamp et al., 1991, Tobler et al., 2006Dickinson et al., 1984). ...
Preprint
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A fundamental assumption of learning theories is that the credit assigned to predictive cues is not simply determined by their probability of reinforcement, but by their ability to compete with other cues present during learning. This assumption has guided behavioral and neural science research for decades, and tremendous empirical and theoretical advances have been made identifying the mechanisms of cue competition. However, when learning conditions are not optimal (e.g., when training is massed), credit assignment is no longer competitive. This is a catastrophic failure of the learning system that exposes the individual's vulnerability to form spurious associations in the real world. Here, we uncover that cue competition can be rescued when conditions are suboptimal provided that the individual has agency over the learning experience. Our findings reveal a new connection between agency over learning and credit assignment to cues, and open new avenues of investigation into the underlying mechanisms.
... The models described previously share the assumption that the response to a stimulus depends only on the associative status of that stimulus and that cue competition occurs in acquisition. In performance-focused models, such as the comparator hypothesis proposed by Miller and Matzel (1988), associations are acquired in a non-competitive fashion, in such a way that all associations are excitatory, and inhibition is a result of the interaction between them, so inhibition is due to a process of comparison between stimuli at the moment of responding, in such a way that responding to a stimulus depends not only on its association with the reinforcer but also on the association with the reinforcer that has been acquired by other stimuli. In our experiments, CI would be the result of this comparison process, as the association between X and the reinforcer is 0, given that they are never presented together, and the comparison term value is high, as it depends on the association between X and A, and the association between A and the reinforcer. ...
Article
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The feature negative discrimination (A+/AX−) can result in X gaining excitatory properties (second-order conditioning, SOC) or in X gaining inhibitory properties (conditioned inhibition, CI), a challenging finding for most current associative learning theories. Research on the variables that modulate which of these phenomena would occur is scarce but has clearly identified the trial number as an important variable. In the set of experiments presented here, the effect of trial number was assessed in a magazine training task with rats as a function of both the conditioning sessions and the number of A+ and AX− trials per session, holding constant the total number of trials per session. The results indicated that SOC is most likely to be found at the beginning of training when there are many A+ and few AX− trials, and CI (as assessed by a retardation test) is most likely to be found at the end of training when there are few A+ and many AX− trials. Both phenomena were also found at different moments of training when the number of A+ trials was equal to the number of AX− trials. These results cannot be predicted by acquisition-focused associative models but can be predicted by theories that distinguish between learning and performance.
... Consequently, the context is likely able to play a larger role in informing behavioral expression of what was learned in that phase. This emphasis on differential strength of LI-context associations is consistent with several different accounts of LI that hinge on cue-context associations (e.g., Miller & Matzel, 1988;Wagner, 1981), all of which do well explaining the high context specificity of LI relative to CI. Although the details of the explanation of differential context specificity differs appreciably across these models, they agree in positing that at least part of the response deficit seen following LI training and subsequent excitatory training is due to a failure to express information that was acquired during the target cue-US excitatory training that constitutes a retardation test. ...
Article
This report is part of a larger project examining associative interference as a function of the nature of the interfering and target associations. Lick suppression experiments with rats assessed the effects of context shifts on proactive outcome interference by latent inhibition (LI) and Pavlovian conditioned inhibition (CI) treatments on subsequently trained Pavlovian conditioned excitation treatment. LI and CI were trained in Context A during Phase 1, and then excitation treatment was administered in Context B during Phase 2, followed by tests for conditioned excitation in Contexts A, B, or C. Experiment 1 preliminarily established our LI and CI treatments and resulted in equally retarded acquisition of behavioral control when the target cue was subsequently trained as a conditioned excitor and tested in Context A. However, only CI treatment caused the target to pass a summation test for inhibition. Centrally, Experiment 2 consisted of LI and CI treatments in Context A followed by excitatory training in Context B. Testing found low excitatory control by both LI and CI cues in Context A relative to strong excitatory control in Context B, but CI treatment transferred to Context C more strongly than LI treatment. Experiment 3 determined that LI treatment failed to transfer to Context C even when the number of LI trials was greatly increased. Thus, first-learned LI appears to be relatively context specific, whereas first-learned CI generalizes to a neutral context. These observations add to existing evidence that LI and CI treatments result in different types of learning that diverge sharply in transfer to a novel test context.
... The finding in Experiment 2 mirrors the similar effect observed when landmarks are trained in compound and tested separately, that is, spatial overshadowing. Prior work from our lab (Wong et al., 2016) found that spatial overshadowing may be best accounted for by acquisition-deficit models (e.g., Rescorla and Wagner, 1972) rather than performance-deficit models (e.g., the comparator hypothesis, Miller and Matzel, 1988). The results from Experiment 2 cannot be based on such accounts because each landmark-target association was well learned during acquisition, and presumably no within-compound landmark-landmark associations had been formed prior to test. ...
Article
We've shown that pigeons can integrate separately acquired spatial maps into a cognitive map. Integration requires an element shared between maps. In two experiments using a spatial-search task in pigeons, we test spatial combination rules when no shared element was present during training. In all three experiments, pigeons first learned individual landmark-target maps. In subsequent tests involving combinations of landmarks, we found evidence that landmarks collaborate in guiding spatial choice at test (Experiment 1). In Experiment 2, pigeons were trained on two landmarks with different proximities to the target. On tests on a compound of both landmarks, pigeons showed stronger spatial control by the more proximal landmark, a performance overshadowing effect. Extinction of the proximal landmark shifted spatial control to the non-extinguished distal landmark. This reveals that the performance overshadowing effect was associative in nature, and not due to perceptual or spatial biases. This emphasis on spatial control during performance reflects the emphasis on performance processes that were a major focus in Ralph Miller's lab.
... A variety of theoretical explanations have been offered for this effect. Some of these theories attribute LI to retrieval failure [2][3][4], other theories attribute it to acquisition failure [5][6][7][8]. With regard to the latter, it has been proposed on more than one occasion that the acquisition failure results from a loss of attention to the CS [9,10]. ...
Article
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Recent studies support the idea that stimulus processing in latent inhibition can vary during the course of preexposure. Controlled attentional mechanisms are said to be important in the early stages of preexposure, while in later stages animals adopt automatic processing of the stimulus to be used for conditioning. Given this distinction, it is possible that both types of processing are governed by different neural systems, affecting differentially the retrieval of information about the stimulus. In the present study we tested if a lesion to the dorso-lateral striatum or to the medial prefrontal cortex has a selective effect on exposure to the future conditioned stimulus (CS). With this aim, animals received different amounts of exposure to the future CS. The results showed that a lesion to the medial prefrontal cortex enhanced latent inhibition in animals receiving limited preexposure to the CS, but had no effect in animals receiving extended preexposure to the CS. The lesion of the dorso-lateral striatum produced a decrease in latent inhibition, but only in animals with an extended exposure to the future conditioned stimulus. These results suggest that the dorsal striatum and medial prefrontal cortex play essential roles in controlled and automatic processes. Automatic attentional processes appear to be impaired by a lesion to the dorso-lateral striatum and facilitated by a lesion to the prefrontal cortex.
... Modified from Mizunami et al. (2009). theory, such as attentional theory (Mackintosh, 1975;Pearce and Hall, 1980) and retrieval theory (Miller and Matzel, 1988), and decisive evidence to discriminate prediction error theory from competitive theories has not been obtained in any learning systems of animals (Miller et al., 1995;Pearce, 2008;Mazur, 2013). Therefore, unambiguous demonstration of the validity of the prediction error theory remains to be achieved. ...
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Revealing neural systems that mediate appetite and aversive signals in associative learning is critical for understanding the brain mechanisms controlling adaptive behavior in animals. In mammals, it has been shown that some classes of dopamine neurons in the midbrain mediate prediction error signals that govern the learning process, whereas other classes of dopamine neurons control execution of learned actions. In this review, based on the results of our studies on Pavlovian conditioning in the cricket Gryllus bimaculatus and by referring to the findings in honey bees and fruit-flies, we argue that comparable aminergic systems exist in the insect brain. We found that administrations of octopamine (the invertebrate counterpart of noradrenaline) and dopamine receptor antagonists impair conditioning to associate an olfactory or visual conditioned stimulus (CS) with water or sodium chloride solution (appetitive or aversive unconditioned stimulus, US), respectively, suggesting that specific octopamine and dopamine neurons mediate appetitive and aversive signals, respectively, in conditioning in crickets. These findings differ from findings in fruit-flies. In fruit-flies, appetitive and aversive signals are mediated by different dopamine neuron subsets, suggesting diversity in neurotransmitters mediating appetitive signals in insects. We also found evidences of “blocking” and “auto-blocking” phenomena, which suggested that the prediction error, the discrepancy between actual US and predicted US, governs the conditioning in crickets and that octopamine neurons mediate prediction error signals for appetitive US. Our studies also showed that activations of octopamine and dopamine neurons are needed for the execution of an appetitive conditioned response (CR) and an aversive CR, respectively, and we, thus, proposed that these neurons mediate US prediction signals that drive appetitive and aversive CRs. Our findings suggest that the basic principles of functioning of aminergic systems in associative learning, i.e., to transmit prediction error signals for conditioning and to convey US prediction signals for execution of CR, are conserved among insects and mammals, on account of the fact that the organization of the insect brain is much simpler than that of the mammalian brain. Further investigation of aminergic systems that govern associative learning in insects should lead to a better understanding of commonalities and diversities of computational rules underlying associative learning in animals.
... The concept of retrieval practice in general is not compatible with contemporary models of associative conditioning because most of these models represent learning purely in terms of storage (i.e., associative) strength. Even models that are retrieval focused (e.g., Miller & Matzel, 1988) represent associative strength in terms of multiple storage strengths that simply interact at test, and they do not account for benefits of retrieval practice. Therefore, the testing effect presents a challenge for associative accounts that have for too long, ignored the role of retrieval processes. ...
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Taking a test of previously studied material has been shown to improve long-term subsequent test performance in a large variety of well controlled experiments with both human and nonhuman subjects. This phenomenon is called the testing effect. The promise that this benefit has for the field of education has biased research efforts to focus on applied instances of the testing effect relative to efforts to provide detailed accounts of the effect. Moreover, the phenomenon and its theoretical implications have gone largely unacknowledged in the basic associative learning literature, which historically and currently focuses primarily on the role of information processing at the time of acquisition while ignoring the role of processing at the time of testing. Learning is still widely considered to be something that happens during initial training, prior to testing, and tests are viewed as merely assessments of learning. However, the additional processing that occurs during testing has been shown to be relevant for future performance. The present review offers an introduction to the historical development, application, and modern issues regarding the role of testing as a learning opportunity (i.e., the testing effect). We conclude that the testing effect is seen to be sufficiently robust across tasks and parameters to serve as a compelling challenge for theories of learning to address. Our hope is that this review will inspire new research, particularly with nonhuman subjects, aimed at identifying the basic underlying mechanisms which are engaged during retrieval processes and will fuel new thinking about the learning-performance distinction. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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When a target conditioned stimulus (CS A) is paired with an unconditioned stimulus in the presence of a second, conditioned stimulus (CS B) during compound conditioning trials, the associative strength of CS B can influence the magnitude of the conditioned response (CR) to CS A. For example, extinction of the competing, nontarget CS B can influence the CR to CS A. An enhancement of the CR to the target CS A due to extinction of the nontarget CS B after compound conditioning is sometimes referred to as "recovery from overshadowing" - a type of retrospective revaluation. The present experiments examined retrospective revaluation effects using a conditioned taste aversion procedure. The experiments obtained an effect on the CR to CS A following extinction of CS B. The results are discussed with respect to the comparator hypothesis, within-compound associations, and retrieval as well as other relationships between the target CS and nontarget CS.
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Recent research has explored cue competition phenomena in social learning. In particular, blocking effects have been observed in the way people learn to infer someone's internal states from their behavioral cues: When people learn to associate a certain behavior with a certain internal state, this blocks their learning of subsequent behavioral cues that also predict the same state, when those cues are presented with the original behavior. In this research, we show that this blocking effect generalizes across targets, such that learning that a behavior predicts an internal state in a person hinders learning that other cues predict the same internal state in a different person, when both behaviors are presented simultaneously. This effect proved robust, and it was not moderated by the group membership of the targets.
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Associative treatments of how Pavlovian conditioning affects conditioned behavior are rudimentary: A simple ordinal mapping is held to exist between the strength of an association (V) between a conditioned stimulus (CS) and an unconditioned stimulus (US; i.e., VCS-US) and conditioned behavior in a given experimental preparation. The inadequacy of this simplification is highlighted by recent studies that have taken multiple measures of conditioned behavior: Different measures of conditioned behavior provide the basis for drawing opposite conclusions about VCS-US. Here, we develop a simple model involving reciprocal associations between the CS and US (VCS-US and VUS-CS) that simulates these qualitative individual differences in conditioned behavior. The new model, HeiDI (How excitation and inhibition Determine Ideo-motion), enables a broad range of phenomena to be accommodated, which are either beyond the scope of extant models or require them to appeal to additional (learning) processes. It also provides an impetus for new lines of inquiry and generates novel predictions.
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Background: In rodents, context specificity of Pavlovian extinction is attenuated by manipulations that impair hippocampal function, including systemic administration of scopolamine, a muscarinic-cholinergic receptor antagonist. Context renewal translates into return of fear following exposure therapy to feared situations. We evaluated the effectiveness of scopolamine for attenuating context renewal of phobic fear in humans. Methods: A total of 60 participants (35 female, 22 male, 1 transgender, 2 undeclared) with social anxiety disorder and fear of public speaking were randomized to placebo, 0.5 mg scopolamine, or 0.6 mg scopolamine. They completed seven exposure sessions in an exposure context and subsequently tested in the exposure context (extinction retest) versus a different context (context renewal test), which were counterbalanced. Testing 1 month later occurred in the exposure context (long-term extinction retest). Fear measures included skin conductance and self-reported distress during speeches. Hippocampus-dependent cognitive tasks were completed as well. Results: Scopolamine augmented extinction across exposure sessions on skin conductance response and skin conductance level. Lower skin conductance response at context renewal in scopolamine groups relative to the placebo group was constrained to simple effects and complicated by unexpected outcomes within placebo and on self-reported fear. Scopolamine led to lower skin conductance response at long-term extinction retest. Scopolamine impaired performance on a cognitive task of hippocampal function. Conclusions: Noninvasive and well-tolerated scopolamine impaired hippocampal processes and augmented extinction during exposure. Drug-free effects persisted 1 month later. Findings at context renewal were limited and suggestive only. Further investigation is warranted with varying scopolamine dosages.
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Evolution of Learning and Memory Mechanisms is an exploration of laboratory and field research on the many ways that evolution has influenced learning and memory processes, such as associative learning, social learning, and spatial, working, and episodic memory systems. This volume features research by both outstanding early-career scientists as well as familiar luminaries in the field. Learning and memory in a broad range of animals are explored, including numerous species of invertebrates (insects, worms, sea hares), as well as fish, amphibians, birds, rodents, bears, and human and nonhuman primates. Contributors discuss how the behavioral, cognitive, and neural mechanisms underlying learning and memory have been influenced by evolutionary pressures. They also draw connections between learning and memory and the specific selective factors that shaped their evolution. Evolution of Learning and Memory Mechanisms should be a valuable resource for those working in the areas of experimental and comparative psychology, comparative cognition, brain–behavior evolution, and animal behavior.
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The reproducibility and reliability of research are fundamental tenets in science, and in animal psychology. In the field of animal psychology, researchers have used a number of different species in various tasks and settings, such that considerations of the reproducibility are necessary compared with human research. Furthermore, using the appropriate statistical analysis and improving experimental design, a concrete theoretical background underlying each research question seems only to be important for improving the reproducibility between experiments in which the same species were used, but also in the situation where different species have been used. Because it is sometimes difficult to standardize the tasks and settings among investigations in animal psychology, theoretical consideration should help improve the reproducibility of research, as well as the validity of the interpretation of results obtained. Such efforts would also contribute to reduce the unnecessary use of animals from the perspective of animal welfare.
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There is evidence that both Pavlovian conditioned inhibition training and CS-alone extinction trials result in a CS that passes a summation and retardation test. The present experiments compared the extent that these two procedures produced a CS that could pass these tests. Such a comparison could provide insight into the kind of inhibitory learning that results, specifically whether two CSs on the nonreinforced trials compete for the acquisition of inhibitory learning. Very little evidence of competition for inhibitory learning has been obtained in previously published studies. Evidence consistent with more inhibition occurring using the Pavlovian CI procedure than extinction was obtained.
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Associative cue competition treatments like blocking reduce behavioral control by a target cue at later test. Interestingly, Pavlovian conditioning experiments have documented that two cue competition treatments can counteract when they are administered together, resulting in less competition with and greater behavioral control by a target CS (for a review, see Wheeler & Miller, 2008). The present experiments confirmed this observation in a human contingency learning procedure. In two human contingency learning experiments, participants received Phase 1 training of two excitatory cues (C and D, A and D, or A and B) followed by Phase 2 ABX + trials. We observed greater ratings to cue X at test by participants who received previous training of both A and B than by participants who received Phase 1 training of A alone. Thus, two blocking cues counteracted in human contingency learning.
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The model elaborated here adapts the influential pooled error term, first described by Wagner and Rescorla (Rescorla & Wagner, 1972; Wagner & Rescorla, 1972), to govern the formation of reciprocal associations between any pair of stimuli that are presented on a given trial. In the context of Pavlovian conditioning, these stimuli include various conditioned and unconditioned stimuli. This elaboration enables the model to deal with cue competition phenomena, including the relative validity effect, and evidence implicating separate error terms and attentional processes in association formation. The model also includes a performance rule, which provides a natural basis for (individual) variation in the strength and nature of conditioned behaviors that are observed in Pavlovian conditioning procedures. The new model thereby begins to address theoretical and empirical issues that were apparent when the Rescorla-Wagner model was first described, together with research inspired by the model over the ensuing 50 years. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
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Prior experience of a stimulus can inhibit subsequent acquisition or expression of a learned association of that stimulus. However, the neuronal manifestations of this learning effect, named latent inhibition (LI), are poorly understood. Here we show that odor pre-exposure produces LI of appetitive olfactory memory performance in Drosophila. Behavioral expression of LI requires that the context during memory testing resembles that during the odor pre-exposures. Odor pre-exposure forms an aversive memory that requires dopaminergic neurons that innervate the γ2α′1 and α3 mushroom body compartments - those to α3 exhibit increasing odor-driven activity with successive pre-exposures. In contrast, odor-specific responses of the corresponding mushroom body output neurons are suppressed. Odor pre-exposure therefore recruits specific dopaminergic neurons that provide teaching signals that attach negative valence to the odor itself. LI of Drosophila appetitive memory consequently results from a temporary and context-dependent retrieval deficit imposed by competition with this short-lived aversive memory.
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In a signal detection theory (SDT) approach to associative learning, one assumes that, when a subject is exposed to a flow of stimuli, an association is created between the internal representations of a cue and of an outcome, allowing the representation of the cue to activate the representation of the outcome. The outcome activation is a random variable drawn from a Gaussian distribution with mean m (sensitivity to the contingency) and standard deviation d (variability in outcome activation). Depending on whether the outcome activation is above or below various decision thresholds, the participant perceives either a negative, a null, or a positive contingency between the cue and the outcome. This study presents a detailed SDT analysis of the performance of four participants on whom data in a contingency assessment task were collected almost daily during several months. Parameters from the SDT model proved relatively stable over time, except if feedback was provided to the subject. In that case, for some participants but not all, the sensitivity increased. The decision criteria were also affected. Some of these changes endured despite the discontinuation of feedback. The variability in outcome activation was not affected by the feedback.
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Prior experience of a stimulus can inhibit subsequent acquisition or expression of a learned association of that stimulus. However, the neuronal manifestations of this learning effect, named latent inhibition (LI), are poorly understood. Here, we show that prior odor exposure can produce context-dependent LI of later appetitive olfactory memory performance in Drosophila. Odor pre-exposure forms a short-lived aversive memory whose lone expression lacks context-dependence. Acquisition of odor pre-exposure memory requires aversively reinforcing dopaminergic neurons that innervate two mushroom body compartments—one group of which exhibits increasing activity with successive odor experience. Odor-specific responses of the corresponding mushroom body output neurons are suppressed, and their output is necessary for expression of both pre-exposure memory and LI of appetitive memory. Therefore, odor pre-exposure attaches negative valence to the odor itself, and LI of appetitive memory results from a temporary and context-dependent retrieval deficit imposed by competition with the parallel short-lived aversive memory.
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Overshadowing refers to the reduced learning or expression of the association between a weaker cue and an outcome in the presence of another stronger cue. The present study broadens the scope of investigation in second language acquisition (SLA), which has mainly focused on inflectional morphology, by extending it to learning two Chinese syntactic constructions, namely the Ba-construction and its SVO counterpart. Thirty L2 Chinese learners were first exposed to the target constructions via watching videos, and were then tested for comprehension and production. The results were three-fold: first and foremost, they yielded evidence of syntactic overshadowing of the Ba-construction by its SVO counterpart, resulting in the reduction of the quantity and quality of the Ba production; second, since the form–meaning mapping was successful for both the Ba and SVO construction, the syntactic overshadowing is more likely to be an expression deficit; and third, the pre-knowledge of verbs further confined the use of the Ba-construction, suggesting a moderating role of word entrenchment in L2 syntactic learning. These findings not only deepen our understanding of overshadowing at the syntactic level, but also offer a fresh perspective for addressing the challenges of L2 learning of the Chinese Ba-construction.
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Dans les trente dernières années, les études de conditionnement classique ont été envisagées sous une perspective cognitive. Cet article passe en revue les principaux travaux qui ont emprunté des notions et une terminologie propres à cette perspective. Après un bref rappel sur les premiers modèles de conditionnement classique (ex. Rescorla-Wagner, 1972), nous présentons les modèles plus récents qui se basent sur les concepts de mémoire et de représentation (ex. Miller et Matzel, 1988). Ces modèles plus récents, qui incorporent la distinction cognitive entre apprentissage et performance, donnent un autre regard sur la nature des liens qui unissent en mémoire les représentations de deux stimuli.
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The correlation between blocking and within-compound memory is stronger when compound training occurs before elemental training (i.e., backward blocking) than when the phases are reversed (i.e., forward blocking; Melchers et al., 2004; 2006). This trial order effect is often interpreted as problematic for performance-focused models that assume a critical role for within-compound associations in both retrospective revaluation and traditional cue competition. The present manuscript revisits this issue using a computational modeling approach. The fit of sometimes competing retrieval (SOCR; Stout & Miller, 2007) was compared to the fit of an acquisition-focused model of retrospective revaluation and cue competition. These simulations reveal that SOCR explains this trial order effect in some situations based on its use of local error reduction.
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Review of the literature indicates that, according to theories of selective attention, learning about a stimulus depends on attending to that stimulus; this is represented in 2-stage models by saying that Ss switch in analyzers as well as learning stimulus-response associations. It is argued that this assumption, however, is equally well represented in a formal model by the incorporation of a stimulus-specific learning-rate parameter, a, into the equations describing changes in the associative strength of stimuli. Previous theories of selective attention have also assumed that (a) Ss learn to attend to and ignore relevant and irrelevant stimuli (i.e., that a may increase or decrease depending on the correlation of a stimulus with reinforcement); and (b) there is an inverse relationship between the probabilities of attending to different stimuli (i.e., that an increase in a to one stimulus is accompanied by a decrease in a to others). The first assumption has been used to explain the phenomena of acquired distinctiveness and dimensional transfer, the second to explain those of overshadowing and blocking. It is argued that although the first assumption is justified by the data, the second is not: Overshadowing and blocking are better explained by the choice of an appropriate rule for changing a, such that a decreases to stimuli that signal no change from the probability of reinforcement predicted by other stimuli. (65 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Three experiments used an autoshaping procedure in 64 female White Carneaux pigeons to investigate the conditioning of the context and of a discrete CS with a food UCS. CS–UCS associations were measured by directed pecking at the key light CS; context–UCS associations were assessed by general activity in the context. Exp I investigated the influence of context–UCS associations on performance to a previously trained CS. The same CS produced greater keypecking in a context of higher associative strength. Exp II examined the influence of context–UCS associations on learning of CS–UCS associations. When tested in a context of fixed associative strength, a CS that had been trained in a context of high associative strength elicited less responding than one trained in a context of low associative strength. Exp III found that signaling a UCS by a discrete CS interfered with the formation of context–UCS associations, as measured both in terms of general activity and ability to promote responding to another CS. Results suggest that the context and the CS compete for association with the UCS. They also suggest that context–UCS associations facilitate the exhibition of CS–UCS associations. (17 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Conditioned lick suppression by water-deprived rats was used to elaborate on recent evidence that the attenuated conditioned response elicited by an overshadowed stimulus may be enhanced by extinction of the overshadowing stimulus with which it had been trained in simultaneous compound. Using a modified serial stimulus arrangement in which a light coexisted with the last half of a tone that terminated with footshock, it was found in Experiment 1 that the tone overshadowed the light. Extinction of the tone-shock association resulted in a virtually complete recovery of the response to the overshadowed light. Using this serial overshadowing procedure, the possibility that the strength of a conditioned response to an element trained in compound covaries as a function of the strength of the response to the other element was tested in Experiment 2. Following overshadowing training similar to that of Experiment 1, independent reinforcement of the overshadowed light, that is, associative inflation, was found to have no deleterious effect on the response to the overshadowing tone. This suggests that the effects of postconditioning extinction and inflation of one element do not have symmetrical effects upon responding to the other element. The results of Experiment 2 were replicated in Experiment 3 using a simultaneous compound stimulus as opposed to the serial compound of the previous studies. These results are discussed in terms of various associative and cognitive models of learning and performance.
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Adult rats were injected with lithium chloride (LiCl) after consumption of a novel flavor (chocolate milk) that either was or was not presented together with a novel ambient odor (banana) as a compound conditioned stimulus (CS). In Experiment 1, the adults’ consumption of the flavor 24 h after conditioning was compared with that of weanling rats given the same conditioning treatment on Postnatal Day 21. The results confirmed previous indications that the reduction in aversion observed for adults conditioned with the compound CS (overshadowing) was weak or nonexistent in weanlings. After a longer retention interval (21 days), there was no evidence of overshadowing in adults despite maintained retention of the basic conditioned aversion. In Experiment 2 this decrease in overshadowing after a long retention interval was replicated with adult animals and extended to a different method of testing. The form of the effect was the same as in Experiment 1: The decrease in overshadowing occurred over the retention interval without loss in retention of the basic taste aversion; the decrease in overshadowing was a consequence of anincrease in the flavor aversion displayed by animals conditioned with the compound CS. The impaired flavor aversion (i.e., the overshadowing) observed shortly after conditioning apparently was due to factors associated with memory retrieval, rather than to reduced attentional or associative strength.
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CS-alone trials or US-alone trials were interpolated between Pavlovian defense conditioning and later measurement of the Pavlovian CR (conditioned suppression of dipper licking). Although both procedures equally degraded the CS-US contingency, only the CS-alone procedure significantly weakened the previously established CR. The US-alone procedure appeared to have no effect.
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Immediately prior to each visually presented target letter string to which the subject made a speeded word-nonword classification response, a visually presented prime to which no overt response was required was shown for 360, 600, or 2,000 msec. For word (W) target trials, the priming event was either a semantically neutral warning signal (Condition NX), a word semantically related to the target word (Condition R), or a word semantically unrelated to the target word (Condition U); for nonword (N) target trials, the priming event was either the neutral warning signal (Condition NX) or a word prime (Condition WP). For the W target trials, reaction times (RTs) were slower in Condition U than in Condition NX and equally so for all three prime durations; RTs were faster in Condition R than in Condition NX and to a greater degree for the 600- and 2,000-msec prime durations than for the 360-msec prime duration. For the N targets, RTs were faster in Condition WP than in Condition NX and equally so for all prime durations. These results were interpreted within the framework of a two-factor theory of attention proposed by Posner and Snyder (1975a).
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Two experiments on conditioned suppression in rats examined overshadowing between visual and auditory components of a compound conditioned stimulus. In the first experiment, when one component was markedly more salient than the other, the more salient overshadowed the less salient, but the latter, although acquiring significant associative strength, did not overshadow the former. When the two components were of approximately equal salience, each overshadowed the other. In the second experiment, reciprocal overshadowing was again observed between two equally salient stimuli, but only when their absolute intensities were relatively low. The failure to observe reciprocal overshadowing under all conditions raises problems for those theories of stimulus selection which assume that stimuli compete for some strictly limited resource. It was suggested, instead, that overshadowing might occur when animals fail to learn to attend to, or actually learn to ignore, stimuli that are not uniquely successful predictors of reinforcement.
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Rats were used in a conditioned-suppression paradigm to investigate why a conditioned inhibition (CS-) does not extinguish when presented alone. Experiment 1 assessed the role of blocking by excitatory contextual cues and/or an evoked representation of the conditioned excitor (CS+), which had been nonreinforced in compound with the CS-. When the CS+ and context were extinguished prior to presentations of the CS- alone, the CS- showed a retardation effect, evidently reflecting latent inhibition, because no inhibition was detected in controls for which presentations of the CS- alone had been omitted. Experiment 2 showed that the loss of conditioned inhibition (CI) was due to excitatory extinction and not to time since conditioning. Furthermore, when excitation was reconditioned to the extinguished CS+ (Experiment 1), or to a novel CS in the same context (Experiment 2), CI was restored. Two other experiments evaluated whether the maintenance of CI depended upon excitation that was generic in form or associatively tied to the training context. They showed no loss of CI when groups received CS+ extinction in that context, along with concomitant presentations in a different context of the US by itself, for a novel CS, or correlated either positively or negatively with the original CS+. Collectively, the findings argue that CI is a "slave" to excitation, for when excitation is extinguished, CI is deactivated; and yet when excitation is reconditioned to the original or a new CS+ in the same or a different context, CI is restored.
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Rats were used in a conditioned-suppression paradigm to assess the effects of contingency variations on responding to a conditioned inhibitor (CS-) and a conditioned excitor (CS+). In Experiment 1, various unconditioned stimulus (US) frequencies were equated across the presence and absence of a CS- in the context of either background cues (continuous-trial procedure) or an explicit neutral event (discrete-trial procedure). With both procedures, a CS-alone treatment enhanced inhibition, whereas treatments involving 50% or 100% reinforcement for the CS- eliminated inhibition without conditioning excitation to that CS. The latter outcome also occurred in Experiment 2, with discrete-trial training equating considerably reduced US frequencies for the presence and absence of the CS-. In further evidence that inhibition was eliminated without conditioning excitation to the CS-, Experiment 3 showed that a novel CS did not acquire excitation when 25%, 50%, or 100% reinforcement was equated across the presence and absence of that CS in the context of a discrete-trial event. Using the procedures of Experiment 1, Experiment 4 showed that a CS+ was extinguished by a CS-alone treatment but was substantially maintained by treatments involving 50% or 100% uncorrelated reinforcement. These effects for a CS+ and a CS- implicate CS-US contiguity, rather than contingency, as the factor determining the extinction of a CS.
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Two experiments are reported that use rats in a conditioned suppression situation. The experiments, designed to remove confounds that have complicated interpretations of prior research, tested the context-blocking hypothesis, the proposition that static apparatus cues or conditioning contexts can block conditioning to discrete conditioned stimuli (CSs). Experiment 1, like previous work, tested for conditioning to the target CS in the same context that had been preconditioned and in which target conditioning had occurred; the experiment demonstrated a context-blocking like effect. Experiment 2 tested for conditioning not only in the preconditioned context but also in a nonpreconditioned context. Evidence for context blocking appeared similar in the two test situations. This suggests that conditioned contexts block the acquisition of associative strength by discrete CSs at the time of target conditioning (e.g., Rescorla & Wagner, 1972) and not through performance factors at the time of testing (e.g., Gibbon & Balsam, 1981).
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Reviews previous free-operant and classical conditioning studies reporting additive summation, suppressive summation, and response averaging to compounded stimuli. A stimulus control model applicable to additive and suppressive summation in both paradigms is presented. A symmetrical composite-stimulus continuum, defined by the on-off states of the discriminative or conditioned stimuli controlling behavior in training, is seen to be common to both types of summation, with the functions of the all-on and all-off continuum extremes interchangeable. Moreover, additive summation, suppressive summation, and response averaging appear to be (a) dependent on discrimination training; and (b) determined by the history of, and immediate relations between, response outputs and reinforcement densities conditioned to particular stimulus values along the composite training dimension. This evidence and the derived stimulus control model are used to functionally relate summation to generalization peak shift. It is suggested that these additive, suppressive, and averaging effects to compounded stimuli might further help in clarifying, and in placing in contextual perspective, what are currently thought of as "excitatory" and "inhibitory" mechanisms in learning. (72 ref.)
Chapter
This chapter examines that Pavlovian conditioning occurs when hedonic stimuli disrupt affective equilibrium, and that an important function of the learning occurs on such occasions to reduce the disruptiveness of subsequent exposures to the same hedonic stimulus. First, the opponent-process theories, and opponent-process phenomena, are introduced to support the notion that conditioned compensatory reactions, which plays a role in behavior, physiology, and experience. Then, the conditioned opponent theory is stated in the form of two postulates, which extend Solomon's and Corbit's theory from the domain of affective regulation to that of Rescorla's and Wagner's theory of Pavlovian conditioning. The chapter reveals the experimental implications of these two postulates and argues that the theory makes sense in the context of instrumental learning and natural selection and considers the prospects for extending the theory. The chapter also suggests that animals should react with maximum vigor and rapid learning to aversive stimuli, which are novel to the particular situations in which they occur. Conditioned opponents may serve to reduce stress in such situations without precluding the possibility that the animal could learn to improve its objective situation.
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The effects of nonreinforced, preconditioning exposures to a CS were investigated in two experiments involving Pavlovian eyelid conditioning in the rabbit. Experiment 1 replicated the often-reported consequent retardation in appearance of conditioned responding, or “latent inhibition effect” (e.g.,Lubow & Moore, 1959;Siegel, 1969). Experiment 2 employed identical training conditions but evaluated whether or not the prehabituated CS would also serve as a “conditioned inhibitor”(Pavlov, 1927). The results indicated that the latent inhibition effect is not the result of the acquisition of active, response-inhibiting properties by the CS, but may be better accounted for in terms of an attentional decrement.
Article
In three experiments we investigated the effect on the performance of thirsty rats of varying the instrumental contingency between lever pressing and the delivery of a saccharin reinforcer. In Experiment 1, the subjects performed more slowly in a non-contingent condition, in which the momentary probability of reinforcement was unaffected by whether or not the animals pressed, than in a contingent condition in which the reinforcer was never presented except following a lever press. This was true of performance under both random ratio and interval schedules in which the function determining the probability of reinforcement following a lever press remained the same across the contingent and non-contingent conditions. Experiment 2 demonstrated that instrumental performance was less affected when the contingency was degraded by the introduction of free reinforcers if these reinforcers were signalled. In Experiment 3, lever pressing was reinstated to some degree after non-contingent training by giving non-reinforced exposure to the operant chamber in the absence of the lever. These results suggest that free reinforcers depress instrumental behaviour through a performance mechanism engaged by their ability to support conditioning of the contextual cues.
Article
Two experiments on conditioned suppression in rats examined the extent to which conditioning to a tone was overshadowed by the presence of a light. When animals received four conditioning trials, a light of moderate intensity significantly overshadowed the tone. On the first trial of conditioning, however, the light had no effect on conditioning to the tone, unless (Experiment I) its intensity was increased, or (Experiment II) it occurred in closer temporal contiguity to reinforcement than the tone. The results establish that overshadowing can occur on the first trial of conditioning, contrary to the predictions of several theories, but suggest that this may be for different reasons from those operating to produce overshadowing over a series of conditioning trials.
Article
Previous research has shown that pretraining with unpredictable CS-UCS presentations subsequently retards the acquisition of autoshaping in pigeons. This result has commonly been interpreted as a general transfer-of-training effect; however, more recently, an alternative interpretation based on blocking by contextual stimuli has been suggested by the observation that the retardation effect is context-specific. Exp I, using 32 pigeons, replicated the finding that pretraining with unpredictable CS-sub-1-UCS presentations subsequently blocks the acquisition of autoshaping (where CS-sub-2 and the UCS are paired) only when pretraining and testing for autoshaping are conducted in the same context. Exp II, with 32 new pigeons, demonstrated that the context-specific retardation effect can be alleviated by extinguishing the context (presenting the context in the absence of the UCS). Exp III, with 24 pigeons, demonstrated that background contextual cues paired with the UCS can function as effective blocking stimuli when subsequently presented coextensively with the visual CS in an autoshaping procedure. (12 p ref)
Article
The possibility of reversing the deficit produced by overshadowing through the use of memory reactivation was investigated. Using lick suppression as a measure of associative strength, water-deprived rats were conditioned in a Pavlovian paradigm which produced reliable overshadowing of a flashing light by a tone. It was found, however, that exposure to the overshadowed stimulus outside of the conditioning context during the retention interval (reminder treatment) caused an increase in lick suppression during testing in animals that had undergone overshadowing, relative to nonreminded overshadowed animals. Subjects that received the reminder treatment but were conditioned without overshadowing showed no increase in lick suppression. Additional control groups ensured that the increase in suppression observed in the overshadowed subjects following reminder treatment was not due to nonspecific fear. The results suggest that the performance deficit produced by overshadowing is due at least in part to a reversible failure to efficiently retrieve associations to the overshadowed stimulus at the time of testing, rather than a failure to form those associations during conditioning.
Article
Using lick suppression by water-deprived rats as an associative index, white noise-footshock pairings resulted in less manifest conditioning when repeated non-reinforced presentations of the white noise preceded conditioning than when no stimulus pre-exposure was given, i.e., latent inhibition was observed. However, the latent inhibition deficit was reduced in animals who received as a reminder treatment shock-alone presentations in another context during the retention interval. Animals conditioned without prior stimulus pre-exposure and those exposed to the white noise and shock unpaired during the conditioning phase of the study showed no change in lick suppression as a result of the reminder treatment. These results suggest that the behavioural deficit produced by non-reinforced pre-exposure to the to-be-conditioned stimulus arises at least in part from a reversible retrieval failure rather than a lack of acquisition.
Article
In classical aversive conditioning experiments, rats do not always learn about all aspects of a compound stimulus predicting shock. A strong stimulus may overshadow a weaker one; and pretraining on one component may block learning about a second component. These results have been explained either by appealing to a notion of selective attention, or by assuming that learning about one component is a function of prior response strength to the entire compound of which it forms a part. In Experiment I, overshadowing was demonstrated on the first trial of conditioning, i.e. before either component had acquired any response strength. In Experiment II, pretraining on one component resulted in complete failure to learn about a second component during compound training, but did not prevent additional learning about the first component. Both results were interpreted as supporting an attentional analysis of blocking and overshadowing.
Article
36 female Wistar or Long-Evans rats were tested in a conditioned fear paradigm to determine whether the extinction of fear of light activates the expression of fear of noise. There was less fear of noise if it had been compounded with the light when paired with shock than if the noise alone had been paired with shock. However, a high level of fear of noise was found in Ss that subsequently underwent extinction of the fear conditioned to light. This finding suggests that overshadowing is not due just to the noise not being associated with shock; it suggests that overshadowing is due in part to a failure of the noise–shock association to be expressed in behavior. (13 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
In Exp I, 32 male hooded Long-Evans rats received either uncorrelated presentations of noises and shocks or a negative correlation procedure in which noises and shocks occurred on alternate days. According to both a retardation and a summation test, the negative correlation caused the noise to become a conditioned inhibitor. Exp II replicated the retardation test of Exp I using different conditioned emotional response parameters and including a no-treatment control. Exps III and IV, with 24 Ss in each, replicated this effect using a retardation and a summation test for inhibition, respectively, and found that the inhibition effect did not occur if a 2nd CS signaled the shocks and therefore blocked conditioning to the background cues. Results indicate that conditioned inhibition, which occurs when a CS and shocks are negatively correlated, is mediated by conditioning to background cues. (16 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Two groups of rats, one which ran the maze with reward, and one which ran the maze without reward, were tested to determine the influence upon the learning curve of a sudden removal, or a sudden introduction, of a food reward. The maze was a 14-unit T-maze. Reliability coefficients ranged from .876 to .965. When the food reward was removed from the maze the error scores and time scores of the rewarded rats showed a large increase. When reward was introduced into the maze the non-rewarded rats showed a large decrease in time and error scores. "The drop in the error curve for the group of rats that were rewarded on the eleventh day brought the curve significantly below the curve of a control group of rats that had been rewarded from the first. This suggests that latent learning may be more effective than overt learning." The relative difficulty of the various blinds shifted as a result of the introduction or removal of réward. The reliability of the maze was higher under reward than under non-reward conditions. Even under non-reward conditions, however, the reliability coefficients based on even-day versus odd-day scores in errors and time were all above .876 ± .024. Bibliography. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Reports data from 3 experiments in support of the encoding specificity hypothesis of retrieval: the effectiveness of retrieval cues depends upon the specific format of encoding of the to-be-remembered (TBR) words at the time of their storage, regardless of how strongly the cues are associated with the TBR words in other situations. In the critical experimental conditions, TBR words were studied in presence of weakly associated cue words. 180 female undergraduates served as Ss. Recall of the TBR words in the presence of these cues was greatly facilitated in comparison with noncued recall; recall of the TBR words in presence of their strongest normative associates, which had not been seen at input, did not differ from noncued recall. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Describes a theory of temporal control which treats responding of animal Ss at asymptote under a variety of learning procedures. Ss are viewed as making estimates of the time to reinforcement delivery using a scalar-timing process, which rescales estimates for different values of the interval being timed. Scalar-timing implies a constant coefficient of variation. Expectancies of reward based on these estimates are formed, and a discrimination between response alternatives is made by taking a ratio of their expectancies. In periodic schedules of reinforcement the discrimination is between local and overall expectancy of reward. In psychophysical studies of duration discrimination, the expectancy ratio reduces the likelihood ratio, and in conjunction with the scalar property, results in a general form of Weber's law. The psychometric choice function describing preference for different amounts and delays of reinforcement also results in a form of Weber's law. (102 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Examined the notion of conditioned inhibition and suggests a definition in terms of the learned ability of a stimulus to control a response tendency opposed to excitation. 2 techniques of measuring inhibition are outlined: (1) the summation procedure in which an inhibitor reduces the response that would normally be elicited by another stimulus, and (2) the retardation of acquisition procedure in which an inhibitor is retarded in the acquisition of an excitatory CR. Examples of the use of these procedures are given for a variety of UCS modalities. Several possible operations for generating conditioned inhibitors are reviewed: extinction following excitatory conditioning, discriminative conditioning, arrangement of a negative correlation between CS and a UCS, use of an extended CS-UCS interval, and presentation of a stimulus in conjunction with UCS termination. These operations suggest that conditioned inhibitors are not generated either by simple extinction procedures or by pairing a stimulus with UCS termination. By contrast, for both salivary and fear conditioning the other procedures do appear to generate inhibitors. Most of the procedures generating conditioned inhibitors can be described as arranging a negatively correlated CS and UCS. (2 p. ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The present experiments explored the relation between a mode of behavior produced by unpredicted presentations of an unconditioned stimulus (US) and subsequent interference with responding to a conditioned stimulus (CS) (the context-blocking effect). The US was food, the CS was a moving ball bearing, and the subjects were rats. The typical response to a moving bearing that predicts food is predatory interaction, and the behaviors that developed under unpredicted US presentations involved focused search and waiting oriented to the food tray. Experiment 1 manipulated the number of unpredicted food presentations and showed that the reduction in subsequent bearing contacts was more clearly related to the occurrence of initial food-tray behavior than to the number of prior food presentations. Experiments 2 and 3 manipulated the conditioning of food-tray behavior while holding constant the number of prior food presentations, and again showed a strong inverse relationship between initial food-tray behavior and ball-bearing contact. The latter experiments also indicated that the locus of interference with bearing-directed behavior was neither primarily central (associative or attentional) nor peripheral (motor interference), but resulted from the incompatibility of two modes of food-getting behavior, a more general predatory search mode versus a mode of focal search and waiting. A behavior-system account of these results does not preclude an associative basis for context-blocking effects, but it argues that such effects may occur at several levels and must function within appetitive structures underlying the animal’s food-getting behavior.
Article
To evaluate a contingency interpretation of conditioned inhibition (CI), rats were given “explicity unpaired” training in which the locus and duration of a CS within the inter-US (shock) interval were systematically manipulated for different groups. Summation and retardation tests in Experiment 1 indicated that stronger CI resulted from both a backward and a trace CS than from a midlocus CS of equal or greater duration. Complementing these findings, the same tests in Experiment 2 showed that, by comparison with novel-stimulus controls, CI developed to a trace CS but not to a mid-locus CS, nor to a trace CS that was accompanied by an immediate signal for the US. These findings argue against a contingency interpretation of CI and favor a contiguity interpretation stressing the short-term rehearsal of stimulus events. Such rehearsal of the US allows a backward CS, but not a mid-locus CS with an extended US-CS interval, to be discriminated as a signal for nonreinforcement, and thus to develop as a conditioned inhibitor. Similarly, excitatory conditioning to the memory trace of a CS allows the nominal trace CS to develop as a signal for nonreinforcement, and thus as a conditioned inhibitor, but not when its memory trace is overshadowed by another CS that immediately precedes the US. In short, the development of CI is facilitated when excitation is mediated by the memorial processing of either the US or a discrete CS for the US rather than by contextual cues.
Article
Conditioned excitation and conditioned inhibition are commonly regarded as mutually exclusive with respect to a single stimulus. Using water-deprived rats in a conditioned lick suppression paradigm, we examined this assumption. In order to avoid associative summation of test context-US (unconditioned stimulus) associations with CS (conditioned stimulus)-US associations, we conducted all CS testing in a neutral context. In Experiment 1, subjects were given 30-s CS presentations reinforced with footshock on a 33% schedule and the absence of the CS was reinforced on either a 68% (negative contingency) or 0% (positive contingency) schedule. The CS trained with negative contingency passed retardation and summation tests for conditioned inhibition, whereas the CS trained with positive contingency did not. In Experiment 2, following exactly the same training that was administered in Experiment 1, a test for conditioned excitation found strong excitation following positive contingency training and weaker but significant excitation following negative contingency training. This demonstrated that a partially reinforced conditioned inhibitor can function as either an inhibitor or an excitor depending on the nature of the test. Experiment 3 examined the basis of excitation supported by the conditioned inhibitor of Experiment 2. Results indicated that this excitation is not evident if the CS is never reinforced, that is, after explicitly unpaired inhibitory training. Thus, a direct CS-US association, rather than second-order conditioning, appears to have been the basis of excitation in Experiment 2. Although the potentials for a CS to act as an excitor and as an inhibitor were found to coexist, the inhibitory value of the CS appeared to increase as a direct function of the excitatory value of the conditioning context, and excitatory value of the CS decreased as a direct function of the conditioning context.
Article
Two conditioned-suppression experiments investigated the effects of prior inhibitory training of A alone upon subsequent reinforcement and nonreinforcement of an AX compound. In Experiment 1, the amount of conditioning to X as a result of reinforcement of AX was increased by previous inhibitory treatment of A and decreased by previous excitatory treatment of A. In Experiment 2, nonreinforcement of AX resulted in the conditioning of a small amount of excitation to X if A alone had a history of inhibitory conditioning. The results are related to a general model of Pavlovian conditioning.
Article
The pigeon's keypeck was investigated in a variety of multiple schedules of response-independent or -dependent reinforcement. Experiments 1 and 2 found that keypecking developed to a reinforcement-associated cue that signaled an increase in local rate of reinforcement, but signaled either no change or a decrease in the overall rate of reinforcement, defined as that prevailing in the cue's absence. In Experiment 3 a greater rate of responding to a target stimulus was observed when it was preceded by a second signal—associated with the same, or a lower, rate of reinforcement—and followed by extinction than when this temporal sequence was reversed. In Experiment 4 responding to a target cue increased when either a temporally prior or a subsequent reinforcement-associated cue was changed to signal extinction. Experiment 5 examined the conditioned reinforcing effectiveness of target cues in two types of situations varying the local context of reinforcement. Stimuli associated with selected target components of a response-dependent multiple schedule of reinforcement could appear as the terminal-link consequences in a two-link chain schedule. Enhanced responding during a target cue which accompanied the introduction of an extinction period following this cue was paralleled by an increase in the conditioned reinforcement effects of this cue. No such increase was found for target cues in which an enhancement of responding had been produced by the interposition of an extinction period prior to the cue.
Article
Memory of a footshock delivered during a single passive avoidance training trial was found to recover in large part from electroconvulsive shock-induced amnesia when a reminder footshock was administered to rats outside the learning apparatus. Systemic control groups proved the behavior of the reminded animals to be specific to the training situation. The recovered memory was found to be stable over repeated test trials and a retention interval of at least five days. The reminder effect was also found to be independent of the interval between training and reminder shock through a minimal range of two hr to two weeks. These findings are interpreted to favor a retrieval failure view of experimental amnesia.
Article
Three experiments are reported in which conditioned lick suppression by water-deprived rats was used as an index of associative strength. In Experiment 1, overshadowing of a light by a tone was observed when the light-tone compound stimulus was paired with foot shock. After initial compound pairings, the tone-shock association was extinguished in one group of subjects. Subsequently, these animals demonstrated significantly higher levels of suppression to the light relative to a control group in which the tone had not been extinguished. Experiment 2 replicated this effect while failing to find evidence to support the possibilities that extinction presentations of the overshadowing tone act as retrieval cues for the light-shock association, or that, via second-order conditioning, the light-shock association is actually formed during extinction of the tone. Experiment 3 determined that the recovery from overshadowing observed in Experiments 1 and 2 was specific to the extinction of the overshadowing stimulus rather than the extinction of any excitatory cue. Collectively, these results suggest that the debilitated response to an overshadowed stimulus does not represent an acquisition failure, but rather the failure of an acquired association to be manifest in behavior.
Article
Four experiments examined the UCS preexposure phenomenon using conditioned suppression of food-reinforced responding as a measure of excitatory conditioning, and electric shock as a UCS. In Experiment 1, groups of rats were preexposed to unsignaled 0.8-mA electric shocks for 0, 1, 3, 5, or 10 days, and then conditioned with a 0.8-mA electric shock. Preexposure to electric shock 1 day prior to conditioning enhanced the acquisition of a CER, whereas preexposure to electric shock for 3, 5, or 10 days prior to conditioning attenuated the acquisition of a CER as a direct function of the number of days of preexposure. In Experiments 2 and 2A, groups of rats were preexposed to unsignaled electric shocks of 0.3, 0.5, 0.8, or 1.3 mA for 10 days, and then conditioned with a 0.8-mA electric shocl. All groups preexposed to electric shock acquired the CER at a slower rate than a group not preexposed to electric shock. The greatest attenuation of CER conditioning occurred when the same intensity electric shock was used during both the preexposure and conditioning phases. In Experiment 3, groups of rats were preexposed to signaled electric shocks of either 0.5, 0.8, or 1.3 mA, and then conditioned with a 0.8-mA electric shock. All groups preexposed to electric shock acquired the CER at a slower rate than a group not preexposed to electric shock. As in Experiments 2 and 2A, the greatest attenuation of CER conditioning occurred when the same intensity electric shock was used during both the preexposure and conditioning phases. In Experiment 4, groups of rats were preexposed to series of 0.5, 0.8, or 1.3-mA electric shocks which they could escape by performing a chain-pull response. Rats in each of these groups had yoked partners which received the same number, intensity, and temporal pattern of electric shocks, but could not perform a response to escape shock. All groups were then conditioned with a 0.8-mA electric shock. Rats preexposed to escapable electric shocks showed equal or greater attenuation of CER conditioning than rats which could not escape shock during the preexposure phase. These results are discussed in terms of nonassociative and associative explanations of the UCS preexposure phenomenon.
Article
The present experiments used pigeons in an autoshaping procedure to examine the effects of a nonreinforced, nontarget stimulus presented during the intertrial interval on responding to a target CS. Experiments 1 and 2 found that a filler stimulus presented during a substantial portion of the ITI retarded responding to the target CS relative to a group not exposed to the filler. This group difference in performance was subsequently abolished by continued training and omitting the filler in the former group (Experiment 1) or adding a filler for the latter group (Experiment 2). Experiment 3 found that when the “filler” occupied most of the interreinforcement interval, CS-US pairings embedded within the “filler” stimulus yielded superior autoshaping relative to a group that received CS-US pairings embedded in static apparatus cues in the absence of the filler. The results are discussed with reference to the ways that a nontarget stimulus during the ITI can influence contextual modulation of responding to a discrete CS and the necessity for comparator theories to incorporate a “local context” view of cycle time to explain the present findings.
Article
In each of three experiments rats were trained by the conditioned-emotional-response technique with a conditioned stimulus (CS) predicting a relatively weak shock, the unconditioned stimulus (US). In the second stage of training the intensity of the shock was increased, and it was found that subjects for whom the same CS was used in both stages acquired further suppression less readily than subjects that experiences a new CS in the second stage. The implication of these results for theories of attention and for theories of habituation is discussed. It is suggested that associations formed by the test CS during the first stage of training reduce the readiness of the stimulus to enter into new associations, either because an association between the stimulus and the context reduces further processing of the stimulus or because the association between the test stimulus and the weak shock attenuates the formation of an association with the stronger shock.