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Recovery of an overshadowed association achieved by extinction of the overshadowed stimulus
Abstract
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.
... Consequently, changes in the associative status of the comparator stimulus after termination of target CS training and before testing should influence responding to the target CS. Supportive of this view, posttraining associative deflation of the comparator stimulus-US association (i.e., extinction of the comparator stimulus) has been found to enhance responding to the target CS (Blaisdell, Gunther, & Miller, in press;Cole, Barnet, & Miller, 1995a;Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985;Matzel, Shuster, & Miller, 1987), and posttraining associative inflation of the comparator stimulus (i.e., reinforcement of the comparator stimulus) has been found to attenuate responding to the target CS (e.g., Denniston, . Thus, the comparator hypothesis appears accurate in positing that responding to a target CS is inversely related to the strength of the comparator stimulus-US association. ...
... ing quantitative changes of the competing stimulus-US association (i.e., effectively decreasing or increasing the strength of the target CS-US association). Decreasing the strength of this association has been demonstrated to enhance responding to the target CS (e.g., see Blaisdell, Gunther, & Miller, in press;Cole et al., 1995a;Kaufman & Bolles, 1981;Matzel et al., 1985;Matzel et al., 1987) and increasing the strength of this association has been demonstrated to attenuate responding to the target CS (e.g., Denniston et al., 1996;. Thus, it would not be surprising if a posttraining manipulation of the temporal attributes of a competing stimulus also affects the way it modulates responding to the target CS. ...
... An explanation of the recovered responding observed to CS X in Experiment 2 based on a decrease in the effective strength of the A-US association is also congruent with the comparator hypothesis without recourse to the temporal coding hypothesis. The comparator hypothesis explicitly predicts that posttraining weakening of the effective A-US association will enhance responding to X (Kaufman & Bolles, 1981;Matzel et al., 1985Matzel et al., , 1987. However, the assumption that shifting Group Update.Diff from A -^ US in Phase 1 to A-^ US in Phase 2 weakened the A-US association is inconsistent with the temporal coding hypothesis, in that the temporal coding hypothesis suggests that the small A-US gap used in the trace conditioning of Group Update.Diff during Phase 2 acted more to alter the learned A-US temporal relationship than to change the strength of the A-US association. ...
Two conditioned lick suppression experiments explored the effects on overshadowing of a posttraining change in the temporal relationship between the overshadowing conditioned stimulus (CS) and the unconditioned stimulus (US). Rats received either trace (Experiment 1) or delay (Experiment 2) overshadowing training. Then pairings of the overshadowing CS and US were given with either a trace or delay temporal relationship. Overshadowing was alleviated by shifting the overshadowing CS–US temporal relationship so that it no longer matched the overshadowed CS–US temporal relationship. These outcomes are explicable in terms of an integration of the comparator hypothesis, which states that cue competition effects (e.g., overshadowing) will be maximal when the information potentially conveyed by competing CSs is equivalent, and the temporal coding hypothesis, which states that CS–US intervals are part of the information encoded during conditioning.
... Kaufman and Bolles (1981) concluded that overshadowing occurred in this study due to the noise not being associated with the electric shock and because the noise-shock association failed to be expressed in their behaviour. Matzel, Schachtman, and Miller (1985) conducted experiments in which conditioned lick suppression by water-deprived rats was used to assess levels of stimulus over-selectivity. It was found that the rats over-selected a tone (over a light) when the light-tone compound stimulus was paired with a shock to their foot. ...
... Subsequently, this group demonstrated significantly higher levels of suppression to the light relative to the control group of rats where the tone had not been extinguished. Matzel and colleagues' (1985) results suggest that over-selective responding "does not represent an acquisition failure, but rather the failure of an acquired association to be manifest in behavior" (Matzel et al., 1985;p.398). Reed et al. (2009) conducted two experiments which examined extinction as a potential remediation strategy for stimulus over-selectivity in both high and low functioning participants with ASC. ...
... Extinction has been widely explored as a potential remediation strategy for stimulus over-selectivity in the literature with various populations. Extinguishing overselected stimuli reduced the importance of one stimulus and allowed previously learned but unexpressed associations to emerge and control behaviour in: White and Silver King pigeons (Wilkie & Masson, 1976), rats (Kaufman & Bolles, 1981;Matzel et al., 1985), children with ASC Leader et al., 2009) and typically developing adults Reynolds et al., 2012). ...
This thesis examined stimulus over-selectivity, a phenomenon where only a limited subset of the total number of stimuli present during discrimination learning controls behaviour. Stimulus over-selectivity is a widely acknowledged problem for an individual’s functioning because it limits learning in situations consisting of multiple and complex cues. This research experimentally demonstrated over-selectivity in both clinical and non-clinical populations, using a discrete trial discrimination paradigm. It investigated the remediating effects of stimulus over-selectivity by manipulating post- learning behaviour by extinguishing the over-selected stimuli. This research examined the correlation between stimulus over-selectivity and several variables, including: attention, cognitive flexibility, behavioural flexibility, stereotyped behaviour, IQ, mental age, chronological age, and severity of autism diagnosis.
Chapters 2 and 3 investigated stimulus over-selectivity in children and adolescents with Autistic Spectrum Conditions (ASC). Chapter 2 examined the effects of level of functioning on degree of over-selective responding. Extinction was investigated as a potential remediation strategy for stimulus over-selectivity. Chapter 3 explored the correlation between stimulus over-selectivity and inflexibility, attention, and stereotyped behaviour to extend the theoretical framework of the concept.
Chapter 4 examined stimulus over-selectivity in typically developing children aged three to seven years. An extinction procedure was employed to test the effects on the previously over-selected and under-selected stimuli, and to evaluate its potential to act as an effective remediation strategy. Chapter 4 also investigated correlations between cognitive flexibility and selective attention with over-selectivity in this non- clinical population. In Chapter 5, extinction was employed to demonstrate its effects on post-test levels of over-selectivity in three age groups of typically developing elderly individuals. This chapter also analysed chronological age, cognitive flexibility and attention levels as correlates of over-selectivity.
The results from the current thesis are discussed in terms of theoretical perspectives of stimulus over-selectivity, and implications for potential remediation strategies.
... Evidence for a performance-deficit account of overshadowing comes from manipulations that occur following overshadowing training and before testing on the overshadowed stimulus. Post-training manipulations that have been found effective in reducing the overshadowing deficit include extinction of the more salient overshadowing CS A (Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985), placement of a long retention interval between overshadowing training and test (i.e., spontaneous recovery; Kraemer, Lariviere, & Spear, 1988), and presenting a US reminder prior to testing (Kasprow, Cacheiro, Balaz, & Miller, 1982). While such findings are not universal to all experimental paradigms (e.g., Holland, 1999), they are sufficiently widespread to have spurred theoretical developments to account for cue competition in terms of expression deficits (e.g., Miller & Matzel, 1988), though some acquisition-deficit theories have been proposed that can also handle these so-called retrospective-revaluation effects (e.g., Dickinson & Burke, 1996;Van Hamme & Wasserman, 1994). ...
... In Experiment 2a, we used an extinction procedure to extinguish spatial control by the overshadowing landmark A and assessed its effects on subsequent spatial control by the overshadowed landmark X (cf. Kaufman & Bolles, 1981;Matzel et al., 1985). On the one hand, if spatial overshadowing reflects an acquisition deficit, as characterized by some models of acquisition (e.g., Mackintosh, 1975;Pearce & Hall, 1980;Rescorla & Wagner, 1972), then no recovery of spatial control by the overshadowed landmark should be observed (cf. ...
... Poor spatial control by X relative to Y therefore suggests overshadowing by more proximal landmark A that accompanied X during training. We then examined whether extinction (Experiment 2a) or retraining (Experiment 2b) of spatial control by overshadowing landmark A would affect subsequent spatial control by overshadowed landmark X. Contrary to what has been found in aversive Pavlovian conditioning and human causal learning paradigms (e.g., Blaisdell et al., 1999;Beckers, Vandorpe, Debeys, & De Houwer, 2009;Dickinson & Burke, 1996;Kaufman & Bolles, 1981;Matzel et al., 1985;Wasserman & Berglan, 1998), but consistent with appetitive Pavlovian conditioning (Holland, 1999), we found no evidence of post-training recovery from overshadowing to X. Our data support the contention that overshadowing in the spatial domain reflects a deficit in learning, as opposed to a deficit in performance. ...
We investigated theoretical accounts of spatial overshadowing using a landmark-based spatialsearch task in a touchscreen preparation with pigeons. Pigeons first learned to find a hidden target on a screen using a compound of two visual cues as landmarks. Landmark A was proximal to the target while landmark X was distal to the target. Experiment 1 replicated our prior spatial overshadowing effect whereby landmark A overshadowed the development of spatial control by X. Spatial control by X was also poorer than by landmark Y which had been paired with the target alone but with the same absolute distance to the target as X had. Thus, the poor spatial control by X was not merely due to the greater X-target distance (relative to the A-target distance). Experiments 2a and 2b failed to find recovery from spatial overshadowing of X through either post-training extinction or counterconditioning of overshadowing landmark A, respectively. We interpret our results as being consistent with acquisition-focused models of elementary associative learning, but not with performance-focused models.
... Thus, little conditioned responding to X is observed at test. Evidence that an X-US association was acquired during overshadowing training comes from manipulations of posttraining deflation (i.e., extinction) of A that recover responding to X at test (e.g., Kanfman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985). Additional reports have shown recovery from other forms of cue competition, such as blocking and the relative stimulus validity effect (e.g., Blaisdell, Gunther, & Miller, 1999;Cole, Bamet, & Miller, 1995;Dickinson & Charnock, 1985). ...
... Thus, possibly the X-B manipulation enhanced attention to X during subsequent testing, thereby increasing responding to X despite overshadowing itself being caused by the acquisition of a relatively weak X-shock association. However, other posttraining manipulations that also successfully reverse overshadowing argue against differences in associative strength as a source of the overshadowing effect (e.g., Blaisdell, Dermiston, & Miller, 1999;Kaufman & Bolles, 1981;Matzel et al., 1985). ...
... This associative threshold view of response elicitation value and protection from cue competition raises another issue. Mentioned above, after overshadowing training, extinguishing the overshadowing stimulus can recover responding to the overshadowed stimulus (Kaufrnan & Bolles, 1981;Matzel et al., 1985). How can we explain the apparent increase in the biological significance of the overshadowed CS (X) as a consequence of extinction of the overshadowing stimulus (A)? ...
In 3 Pavlovian conditioned lick-suppression experiments, rats received overshadowing treatment with a footshock unconditioned stimulus such that Conditioned Stimulus (CS) A overshadowed CS X. Subjects that subsequently received CS X paired with an established signal far saccharin (CS B) exhibited less overshadowing of the X-footshock association than subjects that did not receive the X-B pairings (Experiment I). Experiment 2 replicated this effect and controlled for some additional alternative accounts of the phenomenon. In Experiment 3, this recovery from overshadowing produced by counterconditioning CS X was attenuated if CS B was massively extinguished prior to counterconditioning. These results are more compatible with models of cue competition that emphasize differences in the expression of associations than those that emphasize differences in associative acquisition.
... Some studies have found that A-treatment following AX 3 outcome training evidences positive mediation ("mediated extinction"; e.g., Durlach & Rescorla, 1980;Holland & Forbes, 1982;Nakajima & Kawai, 1997;Rescorla, 1983). Other studies have found posttraining A-trials to enhance conditioned responding to X ("recovery from overshadowing"; e.g., Cole, Oberling, & Miller, 1999;Kaufman & Bolles, 1981;Larkin, Aitken, & Dickinson, 1998;Matzel, Schachtman, & Miller, 1985;Wasserman & Berglan, 1998). Additionally, posttraining devaluation of A sometimes has little or no effect (e.g., Holland, 1999;Oberling, Bristol, Matute, & Miller, 2000). ...
... According to the comparator hypothesis, these extinction trials should weaken Links 2 and 3 and hence the net overshadowing effect. Consistent with this prediction, several investigators (e.g., Cole et al., 1999;Kaufman & Bolles, 1981;Matzel et al., 1985;R. R. Miller, Barnet, & Grahame, 1992) have found that posttraining extinction of the more salient (overshadowing) CS restored robust conditioned responding to the less salient (overshadowed) element of the stimulus compound (but see Holland, 1999;Rauhut et al., 1999). ...
Four conditioned lick suppression experiments with rats examined the effect of trial spacing on cue interaction. Experiments 1 and 2 found overshadowing to be eliminated with massed compound stimulus-outcome pairings and the usual trial spacing effect to be reversed with compound acquisition trials. Experiment 3 found that whether acquisition compound-outcome pairings were massed or spaced determined the effect of posttraining extinction treatment. Extinction of the overshadowing cue reduced responding following massed training and increased responding following spaced training. Extinction of the context decreased responding following massed training. Experiment 4 found the conditioning and devaluation results to be associative and stimulus specific. These results are in accord with the extended comparator hypothesis (J. C. Denniston, H. I. Savastano, & R. R. Miller, 2001).
... For example, after overshadowing training (i.e., AX-US) with A being a more salient CS than X, A has greater associative strength than does X, although X's associative strength is presumably not reduced because of its being trained in compound with A. Presenting X at test activates a direct representation of the US (Link 1 of Figure 2), which is compared with the indirect US representation activated by X sequentially through the X-A association (Link 2 of Figure 2) and the A-US association (Link 3 of Figure 2); hence, the strength of the activated indirect US representation is proportional to the product of these two associations. Because of the strong X-A and A-US associations formed during the overshadowing treatment, the indirectly activated US representation is strong relative to the directly activated US representation, which results in weak conditioned responding to X. Supportive of this view, Kaufman and Bolles (1981) ;Matzel, Schachtman, and Miller (1985); and Matzel, Shuster, and Miller (1987) found that posttraining extinction of A restored responding to X. Presumably, this weakened Link 3 and possibly Link 2 of Figure 2, thereby increasing the magnitude of the directly activated US representation relative to the indirectly activated US representation. ...
... Therefore, a floor effect likely operated here, masking any potential effects of inflation of comparator stimuli. However, prior studies that used posttraining deflation (rather than inflation) treatment identified the context as the comparator stimulus for the CS in latent inhibition studies (Grahame et al., 1994) and the overshadowing cue (A) as the comparator stimulus in overshadowing studies (e.g., Kaufman & Bolles, 1981;Matzel et al., 1985). ...
In 4 conditioned lick suppression experiments with rats, the combined effects of latent inhibition treatment followed by overshadowing treatment were assessed as a test of the comparator hypothesis's (R. R. Miller & L. D. Matzel, 1988) explanations of overshadowing and latent inhibition. Experiments 1 and 2 confirmed the prediction of the comparator hypothesis that combined latent inhibition and overshadowing treatments attenuate the response deficit produced by either treatment alone. Furthermore, consistent with the comparator hypothesis, posttraining changes in the associative status of the putative comparator stimulus altered responding to the target conditioned stimulus (Experiment 3), and switching contexts between latent inhibition and overshadowing treatments (Experiment 4) eliminated the interaction between the latent inhibition and overshadowing treatments.
... Note, however, that attenuated responding to the CS may have reflected a performance, rather than acquisition, deficit. For example, Kaufman and Bolles (1981), Matzel, Schachtman, and Miller (1985), and Matzel, Shuster, and Miller (1987) have shown that when stimulus A overshadows stimulus X (AX + ), posttraining extinction of A results in renewed responding to X. In a similar vein, Matzel, Brown, and Miller (1987) showed recovery from the US prcexposure deficit when animals received context extinction after, as well as before, CS-US training (see also Balaz, Gutsin, Cacheiro, & Miller, 1982). ...
... In a similar vein, Matzel, Brown, and Miller (1987) showed recovery from the US prcexposure deficit when animals received context extinction after, as well as before, CS-US training (see also Balaz, Gutsin, Cacheiro, & Miller, 1982). Performance, rather than acquisition, deficits in overshadowing and blocking strongly support the comparator hypothesis (Miller & Matzel, 1985), which suggests responding to a CS reflects the strength of the CS-US association relative to the strength of other cues present during CS training. It is important to note that this comparison process takes place at the time of testing rather than at the time of training. ...
When an unconditioned stimulus (US) signals the delivery of a second US, there is poor conditioned responding to a conditioned stimulus (CS) that signals the second US. Using an appetitive conditioning preparation with rats, 3 experiments examined the factors that contribute to this poor conditioned responding. In Experiment 1, conditioned responding was improved when US-alone presentations came before, but not after, CS training. Experiment 2 showed that the effect in Experiment 1 was not due to context extinction, and Experiment 3 showed that context-US associations do not significantly contribute to responding in the US–US training procedure. The results show that poor conditioned responding is an acquisition deficit, arising from US, rather than context, signal value.
... Moreover, the effect is seen to apply to retardation tests (Experiment 2s) as readily as to summation tests (Experiment 2A). Both observations are incompatible with the Rescorla-Wagner (1972) model (see Matzel, Schachtman, & Miller, 1985;Matzel, Brown, & Miller, 1987;Matzel, Gladstein, & Miller, 1987;and Schachtman et al., 1987, for additional tests that discriminate between the comparator hypothesis and the Rescorla-Wagner model). Additionally, deflation of an irrelevant excitatory context failed to appreciably attenuate the retardation of conditioned responding that arose from initial inhibitory training. ...
... In support of the view that discrete stimuli presented proximal to a target stimulus can become part of the comparator stimulus, Kaufman and Holies (1981) and Matzel, Schachtman, and Miller (1985) have shown that conditioned responding to an overshadowed stimulus (X) will be greater if the overshadowing stimulus (A) is extinguished prior to testing. One possible interpretation of this effect is that A becomes part of the comparator stimuli for X as a result of AX-US pairings. ...
In the present research water-deprived rats were used in a conditioned lick suppression paradigm to test and further develop Rescorla's (1968) contingency theory, which posits that excitatory associations are formed when a conditioned stimulus (CS) signals an increase in unconditioned stimulus (US) likelihood and that inhibitory associations develop when the CS signals a decrease in US likelihood. In Experiment 1 we found that responding to a CS varied inversely with the associative status of the context in which the CS was trained and that this response was unaltered when testing occurred in a distinctively dissimilar context with a different conditioning history, provided associative summation with the test context was minimized. These results suggest that manifest excitatory and inhibitory conditioned responding is modulated by the associative value of the training context rather than that of the test context. In Experiment 2 it was demonstrated that postconditioning decreases in the associative value of the CS training context reduced the effective inhibitory value of the CS even when testing occurred outside of the training context. Moreover, this contextual deflation effect was specific to the CS training context as opposed to any other excitatory context. Collectively, these studies support the comparator hypothesis, which states that conditioned responding is determined by a comparison of the associative strengths of the CS and its training context that occurs at the time of testing rather than at the time of conditioning. This implies that all associations are excitatory and that responding indicative of conditioned inhibition reflects a CS-US association that is below (or near) the associative strength of its comparator stimulus. It is suggested that response rules which go beyond a monotonic relation between associative value and response strength can partially relieve learning theories of their explanatory burdens, thereby allowing for simpler models of acquisition.
... This phenomenon called 'overshadowing effect', has been widely observed in different animals species (e.g. Mackintosh, 1971;Matzel et al., 1985;Perez et al., 2015) as also in human experiments (e.g. Siegel and Allan, 1985;Baetu and Baker, 2010;Vandorpe and De Houwer, 2005). ...
... In a parallel stream, according to the connectionist approach previously proposed by Mackintosh (Mackintosh, 1975), it has been suggested that when a compound stimulusis used for conditioning, indeed an association is form with each stimulus in the compound even with the less salient one, but 49 they claim that the later retrieval of the less salient cue-US association is some way fails. Following this framework, several post-learning protocols have shown the possibility to 'restore' in some extent the overshadowing effect (Kaufman and Bolles, 1981;Matzel et al., 1985;Sissons et al., 2009). Some of these results can also be explained by Pierce and Hall's model, as when the pairing of a cue with a low associability can be restored presenting the cue without the expected outcome. ...
Through our senses, the brain receives an enormous amount of information. This information needs to be filtered in order to extract the most salient features to guide our behavior. How the brain actually generates different percepts and drives behavior, remain the two major questions in modern neuroscience. To answer these questions, novel neural engineering approaches are now employed to map, model and finally generate, artificial sensory perception with its learned or innate associated behavioral outcome. In this work, using a Go/noGo discrimination task combined with optogenetics to silence auditory cortex during ongoing behavior in mice, we have established the dispensable role of auditory cortex for simple frequency discriminations, but also its necessary role to solve a more challenging task. By the combination of different mapping techniques and light-sculpted optogenetics to activate precisely defined tonotopic fields in auditory cortex, we could elucidate the strategy that mice use to solve this hard task, revealing a delayed frequency discrimination mechanism. In parallel, observations about learning speed and sound-triggered activity in auditory cortex, led us to study their interactions and causally test the role of cortical recruitment in associative learning, revealing it as a possible neurophysiological correlate of saliency.
... And, it has repeatedly been shown that earlier experiences are re-encoded in the light of much later experiences (Matzel, Schachtman et al. 1985, Baker and Mercier 1989, Yin, Grahame et al. 1993, Blaisdell, Gunther et al. 1999, Arcediano, Escobar et al. 2003, Urushihara and Miller 2010. Thus, we want a theory that focuses on (i) how past experience is encoded in memory in a manner that allows it to be re-encoded in the light of later experience, and (ii) how that encoding can be used to predict future experience. ...
... Our computational realization of the minimum-description-length principle's prescription for stochastic model selection explains the results observed in the classic cue competition experiments (Rescorla 1968, Wagner, Logan et al. 1968, Kamin 1969, including the retroactive blocking and unblocking versions of those experiments (Matzel, Schachtman et al. 1985, Yin, Grahame et al. 1993, Blaisdell, Gunther et al. 1999, Urushihara and Miller 2010. ...
... As previously mentioned, overshadowing is observed as a response decrement that results from training a target cue (X) in the presence of another, usually more salient, cue (A). Critically, Kauffman and Bolles (1981; see also Matzel et al., 1985) conducted overshadowing training (AX / US) and subsequently extensively extinguished the overshadowing cue (A) by presenting it in the absence of the outcome. After extinguishing the overshadowing cue, they observed a recovery from overshadowing, that is, strong behavioral control by the overshadowed cue X at test. ...
... Most models that emphasize processing during acquisition (e.g., Rescorla and Wagner, 1972;Wagner, 1981) cannot account for these results for two reasons: (1) they do not have a mechanism that allows learning about absent cues, and (2) these models state that overshadowing results from a deficit in the establishment of the X / US association during overshadowing training, so any manipulation that does not involve the presentation of X should not affect its behavioral control. In fact, recovery from overshadowing after extinguishing the overshadowing cue has been observed repeatedly (e.g., Kaufman and Bolles, 1981;Matzel et al., 1985;Urcelay and Miller, 2006), thereby lending support to a retrieval-failure account of cue competition. A related example is recovery from blocking. ...
Historically, most approaches to understanding learning and memory phenomena, particularly at the neurobiological level, have emphasized information processing that occurs during or soon after training (i.e., acquisition) as critical for observing learned changes in behavior. However, this view has been challenged by studies showing that at least part of the changes observed in behavior are due to constraints at the time of information retrieval. In this chapter, we first analyze behavioral evidence suggesting that retrieval processes, in addition to acquisition processes and storage mechanisms, are critical for observed changes in behavior due to past experience. Then we discuss theoretical approaches that emphasize retrieval processes to explain learning and memory.
... Furthermore, there is some question as to whether the observed competition effects are always due to failure to form associations or instead reflect some kind of performance suppression (Arcediano, Escobar, & Miller, 2004). For example, the cue which was apparently not learned may then show spontaneous recovery after the overshadowing or blocking cue is extinguished (Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985). We do not attempt to review this literature here. ...
... Finally, as noted earlier, stimulus competition effects may not be as robust in animal learning as often assumed in the categorylearning literature (Maes et al., 2016). Further tests can also reveal that what appears to be attenuated stimulus learning was instead a deficit in performance; for example, posttraining extinction of the overshadowing stimulus can reveal that the seemingly unlearned stimulus did acquire associative value (Kaufman & Bolles, 1981;Matzel et al., 1985). Thus, it is possible that the failure to see blocking in category learning may be in keeping with aspects of the associative learning literature that challenge the ubiquity of cue competition in animal learning. ...
Hundreds of associative learning experiments have examined how animals learn to predict an aversive outcome, such as a shock, loud sound, or puff of air in the eye. In this study, we reversed this pattern and examined the role of an aversive stimulus, shock, as a feature of a complex stimulus composed of several features, rather than as an outcome. In particular, we used a category learning paradigm in which multiple features predicted category membership and asked whether a salient, aversive feature would reduce learning of other category features through cue competition. Three experiments compared a condition in which 1 category had among its 6 features a painful "sting" (shock) and the other category a distinctive sound (the critical features) to a control condition in which the sting and sound were represented by much less salient (and not aversive) visual depictions. Subjects learned the categories and then were tested on their knowledge of all 6 features as predictors of the category label. Surprisingly, the experiments consistently found that the salient, aversive critical features did not reduce learning of other features relative to the control. Bayesian statistics gave positive evidence for this null result. Equally surprisingly, in a fourth experiment, a nonaversive salient feature (brightly colored patterns) increased learning of other features compared to the control. We explain the results in terms of attentional strategies that may apply in a category learning context. (PsycINFO Database Record
... As previously mentioned, overshadowing is observed as a response decrement that results from training a target cue (X) in the presence of another, usually more salient, cue (A). Critically, Kauffman and Bolles (1981; see also Matzel et al., 1985) conducted overshadowing training (AX / US) and subsequently extensively extinguished the overshadowing cue (A) by presenting it in the absence of the outcome. After extinguishing the overshadowing cue, they observed a recovery from overshadowing, that is, strong behavioral control by the overshadowed cue X at test. ...
... Most models that emphasize processing during acquisition (e.g., Rescorla and Wagner, 1972;Wagner, 1981) cannot account for these results for two reasons: (1) they do not have a mechanism that allows learning about absent cues, and (2) these models state that overshadowing results from a deficit in the establishment of the X / US association during overshadowing training, so any manipulation that does not involve the presentation of X should not affect its behavioral control. In fact, recovery from overshadowing after extinguishing the overshadowing cue has been observed repeatedly (e.g., Kaufman and Bolles, 1981;Matzel et al., 1985;Urcelay and Miller, 2006), thereby lending support to a retrieval-failure account of cue competition. ...
Historically, most approaches to understanding learning and memory phenomena, particularly at the neurobiological level, have emphasized information processing that occurs during or soon after training (i.e., acquisition) as critical for observing learned changes in behavior. However, this view has been challenged by studies showing that at least part of the changes observed in behavior are due to constraints at the time of information retrieval. In this chapter, we first analyze behavioral evidence suggesting that retrieval processes, in addition to acquisition processes and storage mechanisms, are critical for observed changes in behavior due to past experience. Then we discuss theoretical approaches that emphasize retrieval processes to explain learning and memory.
... Second, if the target CS is absent but the US is present on a given trial, the associative strength of the CS should decrease. Through these mechanisms, the model is able to explain empirical retrospective revaluation, including backward blocking and recovery from various cuecompetition effects such as those that result from posttraining extinction of competing stimuli including overshadowing (Kaufman & Holies, 1981;Matzel et al., 1985Matzel et al., , 1987, the relative stimulus validity effect (Cole, Barnet, & Miller, 1995a), blocking (Blaisdell, Gunther, & Miller, 1999), and overexpectation (Blaisdell, Denniston, & Miller, 2000). It is important that this account depends on new learning occurring to the target CS retrospectively. ...
Empirical retrospective revaluation is a phenomenon of Pavlovian conditioning and human causal judgment in which posttraining changes in the conditioned response (Pavlovian task) or causal rating (causal judgment task) of a cue occurs in the absence of further training with that cue. Two experiments tested the contrasting predictions made by 2 families of models concerning retrospective revaluation effects. In a conditioned lick-suppression task, rats were given relative stimulus validity training, consisting of reinforcing a compound of conditioned stimuli (CSs) A and X and nonreinforcement of a compound of CSs B and X, which resulted in low conditioned responding to CS X. Massive posttraining extinction of CS A not only enhanced excitatory responding to CS X, but caused CS B to pass both summation (Experiment 1) and retardation (Experiment 2) tests for conditioned inhibition. The inhibitory status of CS B is predicted by the performance-focused extended comparator hypothesis (J. C. Denniston, H. I. Savastano, & R. R. Miller, 2001), but not by acquisition-focused models of empirical retrospective revaluation (e.g., A. Dickinson & J. Burke, 1996; L. J. Van Hamme & E. A. Wasserman, 1994).
... The second interpretation is that acquisition of the target CS-US association was impaired as a result of overshadowing of the CS by the local training context, as would be anticipated on the basis of Rescorla and Wagner's (1972) model or Wagner's (1981) SOP model. This interpretation assumes that overshadowing reflects an acquisition deficit as opposed to a performance deficit (e.g., Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985); however, if overshadowing is viewed as a performance deficit, this interpretation converges with the view of the comparator hypothesis. ...
A potential basis for trial spacing and trial distribution effects was investigated in rats. In Experiment 1, a conditioned stimulus (e.g., CS A) was trained with either massed (e.g., A → A → A) or spaced (e.g., A ——→ A ——→ A) trials. When trials were massed, brief exposure to the training context (a condition typical of massed training) impaired responding, whereas more extensive exposure to the context during or after training reduced this apparent massed trials deficit. In Experiment 2, different CSs were trained in either a massed (e.g., A → A → A → B → B → B → C → C → C) or a distributed (e.g., A → B → C → A → B → C, etc.) manner. Trials massed in this sense resulted in impaired responding to the CS, and this impairment was attenuated by posttraining extinction of the context cues. Thus, trial distribution and apparent trial spacing effects are at least in part reversible deficits in performance rather than failures of learning.
... In each of those cases the degree of behavioral control by positive versus negative stimuli or by some aspect of training stimuli was revealed or magnified during extinction. In a somewhat similar vein, Kaufman and Holies (1981) and Matzel, Schachtman, and Miller (1985) reported that a previously overshadowed stimulus exerted a strong effect of its own only after the association between the overshadowing stimulus and the US had been extinguished. These authors viewed overshadowing mainly as a failure of some acquired association to be expressed in behavior rather than as a lack of acquisition of the association. ...
Various discriminations based on the presence versus absence of a single feature are supposedly learned much better when the feature appears on reinforced rather than nonreinforced trials. However, failures to show discriminative acquisition with the feature on negative trials could reflect a deficiency in control of performance rather than a lack of learning. Five experiments supported this alternative possibility. Pigeons that had yielded little or no evidence of learning (with distinguishing features like a small white square on the response key or a tone located some distance away) revealed clear differences between keypecking to the formerly positive and negative stimuli when all food was removed from the situation. Besides extinction, several other procedures for decreasing the positive predictiveness of the most informative stimulus element also unmasked feature-negative learning, whereas general and specific contextual changes did not. Incompletely mastered feature-positive discriminations improved during extinction, too. The findings of better discrimination performance in extinction were related to analogous effects in previous generalization and discrimination research employing other tasks and arrangements. A sign-tracking analysis could not completely account for the present results.
... The magnitude of this retrospective revaluation effect depends on several parameters. For example, longer durations of compound-cue exposure or of revaluation produce a stronger effect (e.g., Blaisdell et al., 1999;Larkin et al., 1998;Matzel et al., 1985). The physical or functional similarity between cues also appears to determine the direction of post-revaluation change; more distinctive cues produce the revaluation effect, whereas more similar cues result in reduced responding to all cues (mediated extinction; e.g., Balleine et al., 2005;Liljeholm & Balleine, 2009).These retrospective revaluation effects are thought to arise due to within-compound stimulus associations; associations between overselected and underselected cues form during discrimination training, so when the overselected cue is extinguished in revaluation, a representation of the underselected cue may be "activated" associatively, resulting in changes in control by that cue (e.g., Dickinson & Burke, 1996;Van Hamme & Wasserman, 1994;see Miller & Witnauer, 2016, for a brief overview of associative accounts of retrospective revaluation). ...
Stimulus overselectivity describes strong control by one stimulus element at the expense of other equally relevant elements. Research suggests that control by underselected stimuli emerges following extinction of the overselected stimulus ("revaluation") and the emergence is larger when overselectivity is greater. We compared such revaluation effects with a control compound or condition in two experiments. Human participants chose between compound S+ and S- stimuli. Then, to assess control by compound-stimulus elements, participants chose between individual elements in a testing phase without feedback. The S+ element chosen most often (the overselected element) underwent revaluation, during which choice of that element was extinguished and choice of a novel element reinforced. Thereafter, participants completed a retesting phase. Revaluation reduced choice of the overselected element. Choice of the underselected element decreased for participants with low overselectivity but increased for participants with high overselectivity. This was not the case for a control compound that did not undergo revaluation (Experiments 1 and 2) or in a control condition in which the overselected element continued to be reinforced during revaluation (Experiment 2). These findings suggest that overselectivity levels may modulate revaluation effects, and they also highlight the importance of the contingency change in postrevaluation changes in stimulus control.
... Furthermore, inspired by overshadowing designs in the conditioning literature (Kamin, 1968;Tennant & Bitterman, 1975), the present design allows for examination of learning when auditory category regularities are redundant with visuomotor sequence regularities (Category + Sequence (Category Violation), Sequence + Category (Sequence Violation) and thus potentially carry less informational value. Overshadowing, the observation that when joint information sources (X, Y; here, e.g., visuomotor sequence and auditory category regularities) predict the same outcome, subsequent response to either X or Y alone is less robust than had X and Y been learned in isolation (Kamin, 1968;Matzel et al., 1985). Thus, the redundant regularities in the two conditions mentioned above might be expected to hinder learning, as in overshadowing effects, because a fixed amount of associative strength is available and distributed across multiple cues (as, e.g., in the Rescorla-Wagner model, 1972). ...
The environment provides multiple regularities that might be useful in guiding behavior if one was able to learn their structure. Understanding statistical learning across simultaneous regularities is important, but poorly understood. We investigate learning across two domains: visuomotor sequence learning through the serial reaction time (SRT) task, and incidental auditory category learning via the systematic multimodal association reaction time (SMART) task. Several commonalities raise the possibility that these two learning phenomena may draw on common cognitive resources and neural networks. In each, participants are uninformed of the regularities that they come to use to guide actions, the outcomes of which may provide a form of internal feedback. We used dual-task conditions to compare learning of the regularities in isolation versus when they are simultaneously available to support behavior on a seemingly orthogonal visuomotor task. Learning occurred across the simultaneous regularities, without attenuation even when the informational value of a regularity was reduced by the presence of the additional, convergent regularity. Thus, the simultaneous regularities do not compete for associative strength, as in overshadowing effects. Moreover, the visuomotor sequence learning and incidental auditory category learning do not appear to compete for common cognitive resources; learning across the simultaneous regularities was comparable to learning each regularity in isolation.
... Eventually, the associative strength of EP signal is inhibited so that CP signal blocks learning about EP signal, which implies the long-term effect of overshadowing over time leading to blocking. 4. Recovery from overshadowing (Matzel et al. 1985) and recovery from blocking (Arcediano et al. 2001) are both recovered through the extinction of the more salient CP signal, so that the less salient EP signal obtains enough associative learning. ...
In the field of second language acquisition, overshadowing and blocking by cue competition effects in classical conditioning affect the learning and expression of human cognitive associations. In this work, a memristive neural network circuit based on neurobiological mechanisms is proposed, which consists of synapse module, neuron module, and control module. In particular, the designed network introduces an inhibitory interneuron to divide memristive synapses into excitatory and inhibitory memristive synapses, so as to mimic synaptic plasticity better. In addition, the proposed circuit can implement six functions of second language acquisition conditioning, including learning, overshadowing, blocking, recovery from overshadowing, recovery from blocking, and long-term effect of overshadowing over time leading to blocking. Overshadowing, which denotes that the more salient stimulus overshadows the learning of the less salient stimulus when two stimuli differ in salience, reduces the associative strength acquired by the less salient stimulus. Blocking, which indicates that pretraining on one stimulus blocks learning about a second stimulus, inhibits the associative strength acquired by a second stimulus. Finally, the correctness and effectiveness of implementing functions mentioned above are verified by the simulation results in PSPICE. Through further research, the proposed circuit is applied to bionic devices such as social robots or educational robots, which can address language and cognitive disorders via assisted learning and training.
... Our results suggest that learning occurs automatically, but the influence of this learning on behavior depends on reasoning about the meaning of the associations. This is consistent with, for example, retrieval-based theories (e.g., Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985). There is an ongoing discussion about the conditions under which cue competition effects occur. ...
In this article, I review research on incidental learning of simple stimulus-response regularities. The article summarizes work with the colour-word contingency learning paradigm and related simple learning procedures. In the colour-word contingency learning paradigm participants are presented with a coloured neutral word on each trial and are asked to ignore the word and respond to the print colour (e.g., similar to a Stroop procedure). Distracting words are typically colour-unrelated neutral stimuli. However, each distracting word is presented most often in one target colour (e.g., "move" most often in blue, "sent" most often in green, etc.). Learning of these contingencies is indicated by faster and more accurate responses to high contingency trials (in which the word is presented with its frequent colour) relative to low contingency trials. This procedure has proven useful for investigations in incidental learning. The present manuscript summarizes the existing work with this (and related) learning procedures and highlights emerging directions.
... Recovery from overshadowing (Matzel et al., 1985). In the overshadowing experiment, the extinction of the 1 CS will lead to an increased responding to the 2 CS . ...
Classical conditioning plays a critical role in the learning process of biological brains, and many computational models have been built to reproduce the related classical experiments. However, these models can reproduce and explain only a limited range of typical phenomena in classical conditioning. Based on existing biological findings concerning classical conditioning, we build a brain-inspired classical conditioning (BICC) model. Compared with other computational models, our BICC model can reproduce as many as 15 classical experiments, explaining a broader set of findings than other models have, and offers better computational explainability for both the experimental phenomena and the biological mechanisms of classical conditioning. Finally, we validate our theoretical model on a humanoid robot in three classical conditioning experiments (acquisition, extinction, and reacquisition) and a speed generalization experiment, and the results show that our model is computationally feasible as a foundation for brain-inspired robot classical conditioning.
... The literature on context reinstatement (e.g., Godden & Baddeley, 1975) indicates that having the same contextual information present during learning and at test enhances recall (although the effect has in some cases failed to materialise, for example, Fernandez & Glenberg, 1985;Saufley et al., 1985). Second, benefits may be reduced when learners focus on information intrinsic to the to-be-learned materials at the expense of environmental cues during encoding (Matzel et al., 1985) or retrieval (Smith, 1994). ...
Students are often advised to do all of their studying in one good place, but restudying to-be-learned material in a new context can enhance subsequent recall. We examined whether there are similar benefits for testing. In Experiment 1 (n = 106), participants studied a 36-word list and 48 hr later—when back in the same or a new context—either restudied or recalled the list without feedback. After another 48 hr, all participants free-recalled the list in a new context. Experiment 2 (n = 203) differed by having the testing-condition participants restudy the list before being tested. Across both experiments, testing in a new context reduced recall, which carried over to the final test, whereas restudying in a new context did not impair (and in Experiment 2, significantly enhanced) recall. These findings reveal critical interactions between contextual-variation and retrieval-practice effects, which we interpret as consistent with a distribution-of-memory-strengths framework.
... Cela est conforme, par exemple, aux comptes rendus basés sur la récupération (e.g., Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985). Il y a une discussion continue sur les conditions dans lesquelles les effets de la compétition entre indices se produisent. ...
Dans cet article, je passe en revue la littérature sur l’apprentissage incident des régularités simples de stimulus-réponse. L’article résume les travaux utilisant le paradigme d’apprentissage de contingence couleur-mot et les procédures connexes. Dans ce paradigme, un mot neutre coloré est présenté aux participants à chaque essai et ces derniers sont invités à ignorer le mot et à répondre à la couleur d’impression. Chaque mot distracteur est présenté le plus souvent dans une couleur cible (p. ex., « bouge » le plus souvent en bleu, etc.). L’apprentissage de ces contingences est indiqué par des réponses plus rapides et plus précises aux essais de forte contingence (dans lesquels le mot est présenté fréquemment avec sa couleur) par rapport aux essais de faible contingence. Cette procédure s’est avérée utile pour les recherches portant sur l’apprentissage incident. Le présent manuscrit résume le travail existant avec cette procédure d’apprentissage et celles connexes, et met en évidence les orientations émergentes.
... There are other factors that are also known to influence the magnitude of RR: For example, the strength of the within-compound associations between the stimuli, so that the stronger the association, the higher the probability of observing a RR effect (Aitken, Larkin & Dickinson, 2001). In addition, RR is more readily observed with longer CS durations (Matzel, Schachtman & Miller, 1985). Moreover, a large number of revaluation trials seems to be required to produce a robust RR effect (Blaisdell, Gunther & Miller, 1999). ...
In this article a formal model of associative learning is presented that incorporates representational and computational mechanisms that, as a coherent corpus, empower it to make accurate predictions of a wide variety of phenomena that, so far, have eluded a unified account in learning theory. In particular, the Double Error Dynamic Asymptote (DDA) model introduces: (a) a fully connected network architecture in which stimuli are represented as temporally clustered elements that associate to each other, so that elements of one cluster engender activity on other clusters, which naturally implements neutral stimuli associations and mediated learning; (b) a predictor error term within the traditional error correction rule (the double error), which reduces the rate of learning for expected predictors; (c) a revaluation associability rate that operates on the assumption that the outcome predictiveness is tracked over time so that prolonged uncertainty is learned, reducing the levels of attention to initially surprising outcomes; and critically (d) a biologically plausible variable asymptote, which encapsulates the principle of Hebbian learning, leading to stronger associations for similar levels of cluster activity. The outputs of a set of simulations of the DDA model are presented along with empirical results from the literature. Finally, the predictive scope of the model is discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
... However, once the participant is explicitly instructed to learn the contingencies, the influence of this passive learning on performance is no longer observed, perhaps indicating suppression of the knowledge of the pairings by explicit decisional processes. This notion bears some resemblance to retrieval-based theories of cue competition effects, which argue that acquired contingencies are suppressed at retrieval test (see Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985; see R. R. ...
Overshadowing and blocking are two important findings that are frequently used to constrain models of associative learning. Overshadowing is the finding that learning about a cue (referred to as X) is reduced when that cue is always accompanied by a second cue (referred to as A) during the learning phase (AX). Blocking is the finding that after learning a stimulus-outcome relation for one stimulus (A), learning about a second stimulus (X) is reduced when the second stimulus is always accompanied by the first stimulus (AX). It remains unclear whether overshadowing and blocking result from explicit decision processes (e.g., "I know that A predicts the outcome, so I am not sure whether X does, too"), or whether cue competition is built directly into low-level association formation processes. In that vein, the present work examined whether overshadowing and/or blocking are present in an incidental learning procedure, where the predictive stimuli (words or shapes) are irrelevant to the cover task and merely correlated with the task-relevant stimulus dimension (colour). In two large online studies, we observed no evidence for overshadowing or blocking in this setup: (a) no evidence for an overshadowing cost was observed with compound (word-shape) cues relative to single cue learning conditions, and (b) contingency learning effects for blocked stimuli did not differ from those for blocking stimuli. However, when participants were given the explicit instructions to learn contingencies, evidence for blocking and overshadowing was observed. Together, these results suggest that contingencies of blocked/overshadowed stimuli are learned incidentally, but are suppressed by explicit decision processes due to knowledge of the contingencies for the blocking/overshadowing stimuli.
... The comparison of direct and indirect US representations is computed by simple subtraction of the indirectly activated US representation from the directly activated US representation. This comparison process allows the comparator hypothesis to account for a wide variety of cue competition phenomena (e.g., overshadowing, blocking, and overexpectation), including retrospective revaluation (e.g., backward blocking as a result of posttraining reinforcement of the comparator stimulus and recovery from overshadowing as a result of posttraining extinction of the comparator stimulus; e.g., Kaufman & Bolles, 1981;Matzel, Schachtman, & Miller, 1985;Shanks, 1985). However, the comparator hypothesis has no mechanism for allowing inhibition of a potential comparator stimulus, and certainly even if it did, it would predict a sort of superconditioning because inhibiting the comparator stimulus would merely suppress competition, thereby increasing responding to the target cue. ...
This series examines the associative basis of inhibitory perceptual learning. Four experiments demonstrate that inhibitory perceptual learning, like Pavlovian conditioned inhibition, is affected by manipulating the number of training trials. Specifically, many interspersed XB/AB training trials (in which letters represent initially neutral stimuli such as tones, clicks, and flashing lights) followed by A–US pairings caused X to act like a conditioned inhibitor (Experiment 1), which is presumed to suggest that an inhibitory association between conditioned stimuli X and A had been formed (i.e., inhibitory perceptual learning). Conversely, few XB/AB training trials followed by A–US pairings produced conditioned responding to X (Experiment 2), which suggests that an excitatory association between X and A had been formed. Additionally, associations with the common element, B, appear to play an inconsistent role across inhibitory and excitatory perceptual learning situations, as extinction of B attenuated excitatory (Experiment 3) but failed to have an influence after inhibitory (Experiment 4) pretraining. The viability of several different accounts of perceptual learning is discussed in light of these observations.
... RR refers to a change on the effect that a trained cue produced on behavior (typically a CS), that occurs after giving further training to a different cue. In Pavlovian conditioning, Kaufman and Bolles (1981) first reported RR in an overshadowing experiment with rats (see also Matzel et al., 1985). A noise-light compound was paired with an electric shock in one group. ...
An occasion setter (OS) is a stimulus or context with the capacity to disambiguate an ambiguous conditioned stimulus (CS). Previous research has shown that OSs share some features with regular Pavlovian CSs. Amongst them, research has shown that OSs are subject to blocking; that is, a new OS exerts reduced behavioral control after training in compound with a previously established OS. Of additional interest, in Pavlovian blocking, it has been reported that a blocked CS comes to elicit conditioned responding after the extinction of the blocking CS. This is an example of retrospective revaluation, a family of phenomena in which the response to a specific stimulus is modified by training a related cue.
Here, three experiments sought to extend the analogies between OS and Pavlovian conditioning by examining the blocking of OSs and its retrospective revaluation. In all experiments, an OS was established by pairing a CS with food in the presence of the OS, but not in its absence (i.e., positive OS). Blocking was then trained by presenting the OS in compound with a novel OS. Experiment 1 showed blocking of the second OS, but direct exposure to the blocking OS did not enhance responding to the second OS. Experiment 2 replicated the blocking effect but subsequent training of the blocking OS with a reversed contingency showed no retrospective revaluation. Experiment 3 examined whether blocking of the OS occurred with a novel CS during the compound phase. In this experiment blocking was again observed, but only when subjects were tested with the original CS. These results are discussed focusing on the underlying links at work in occasion setting.
... Debido quizá al hecho de que existen efectos similares entre ambos procedimientos. Así, cuando se extingue el EC de mayor saliencia o el contexto en su caso, la RC al EC ensombrecido o al EC aumenta (Matzel, Schachtman & Miller, 1985;Balsam, 1985;Wasserman & Berglan, 1998;Cole, Oberling & Miller, 1999;Chang, Stout, & Miller, 2004). ...
... There are other factors that are also known to influence the magnitude of RR: For example, the strength of the within-compound associations between the stimuli, so that the stronger the association, the higher the probability of observing a RR effect (Aitken, Larkin & Dickinson, 2001). In addition, RR is more readily observed with longer CS durations (Matzel, Schachtman & Miller, 1985). Moreover, a large number of revaluation trials seems to be required to produce a robust RR effect (Blaisdell, Gunther & Miller, 1999). ...
In this paper a formal model of associative learning is presented which incorporates representational and computational mechanisms that, as a coherent corpus, empower it to make accurate predictions of a wide variety of phenomena that so far have eluded a unified account in learning theory. In particular, the Double Error model introduces: 1) a fully-connected network architecture in which stimuli are represented as temporally distributed elements that associate to each other, which naturally implements neutral stimuli associations and mediated learning; 2) a predictor error term within the traditional error correction rule (the double error), which reduces the rate of learning for expected predictors; 3) a revaluation associability rate that operates on the assumption that the outcome predictiveness is tracked over time so that prolonged uncertainty is learned, reducing the levels of attention to initially surprising outcomes; and critically 4) a biologically plausible variable asymptote, which encapsulates the principle of Hebbian learning, leading to stronger associations for similar levels of element activity. The outputs of a set of simulations of the Double Error model are presented along with empirical results from the literature. Finally, the predictive scope of the model is discussed.
... The RW equation captures many of the general properties of reinforcement learning, at the organismal and neuronal level (Schultz and Dickinson 2000); however, the anticipated outcome is described by a point estimate. This results in a number of well-known problems, including how to understand blocking, overshadowing (Matzel et al. 1985), relapse after extinction (Bouton 2002;Dunsmoor et al. 2015), instrumental transfer (Cartoni et al. 2013), and facilitated relapse after extinction-several problems that are explicable if we model reinforcement in a Bayesian framework (Kruschke 2008;Maia 2009;Gershman 2015;Courville et al. 2006). Moreover, point-estimate models of belief are inconsistent with several suggestive findings in psychology. ...
Probabilistic decision-making is a general phenomenon in animal behavior, and has often been interpreted to reflect the relative certainty of animals' beliefs. Extensive neurological and behavioral results increasingly suggest that animal beliefs may be represented as probability distributions, with explicit accounting of uncertainty. Accordingly, we develop a model that describes decision-making in a manner consistent with this understanding of neuronal function in learning and conditioning. This first-order Markov, recursive Bayesian algorithm is as parsimonious as its minimalist point-estimate, Rescorla-Wagner analogue. We show that the Bayesian algorithm can reproduce naturalistic patterns of probabilistic foraging, in simulations of an experiment in bumblebees. We go on to show that the Bayesian algorithm can efficiently describe the behavior of several heuristic models of decision-making, and is consistent with the ubiquitous variation in choice that we observe within and between individuals in implementing heuristic decision-making. By describing learning and decision-making in a single Bayesian framework, we believe we can realistically unify descriptions of behavior across contexts and organisms. A unified cognitive model of this kind may facilitate descriptions of behavioral evolution.
... This view suggests that over-selectivity is not an acquisition, but a performance problemwith some stimuli, although learned about, not controlling behavior because of their relative lack of importance. It has been noted that extinguishing the over-selected stimuli allows the previously under-selected stimuli to control behavior with no additional training, suggesting that the latter were acquired but did not control behavior while the over-selected cues were present Matzel et al. 1985;Reed et al. 2009;Reynolds et al. 2012;Wilkie and Masson 1976). ...
Introduction:
Stimulus overselectivity describes a phenomenon where an individual responds only to a subset of the stimuli present in the environment, and, thus, may restrict learning regarding the range, breadth, or number of features, of a stimulus (Farber, Dickson, & Dube, 2017; Kelly, Leader, & Reed, 2015; Reed, 2017). Instances of overselective responding are found in many clinical populations that experience some assault to their levels of cognitive function, including individuals with intellectual disabilities, learning disabilities, acquired brain injury, and schizophrenia as well as typically developing individuals experiencing situations involving increased cognitive demands (Kelly, Leader, & Reed, 2016; Reed, Savile, & Truzoli, 2012; Reynolds, Watts, & Reed, 2012). Stimulus overselectivity is very often noted in individuals with autism (Kelly et al., 2015; Leader, Loughnane, McMoreland, & Reed, 2009; Reed, Broomfield, McHugh, McCausland, & Leader, 2009), and this failure to respond to all necessary or important cues in the environment may be a factor contributing to many of the problems seen in autism, including deficits during observational learning, learning with prompts or learning during matching-to-sample tasks (see reviews by Kelly, 2012 and Ploog, 2010).
One well-researched theoretical perspective regarding stimulus overselectivity is the ‘attention deficit’ view, which posits that overselective responding is a product of an attentional deficit in sampling all of the component elements of a stimulus (see Dube et al., 2009). The first aim of the current study was to explore the relationship between attention and overselective responding in children with autism. Overselective stimulus control can be related to a number of aspects of cognitive function, such as levels of intellectual functioning (see Kelly et al., 2015), and levels of executive function, especially as indexed by cognitive flexibility (Gard, Hölzel, & Lazar, 2014). The second aim of the current study was to analyse the association between stimulus overselectivity and cognitive flexibility in children with autism.
Method:
Twenty-four children, 12 diagnosed with autism (experimental group) and 12 mental age matched typically developing children (control group), participated in the current study. Levels of stimulus overselctivity were measured using a discrete trial discrimination paradigm, as utilised by Kelly et al. (2016; 2015). Selective attention, sustained attention and attentional switching were measured using the Test of Everyday Attention for Children (TEA-Ch; Manly, Robertson, Anderson & Nimmo-Smith, 1999). Cognitive flexibility was measured using the computer-based Intra/Extra Dimensional Set Shift (IED; Cambridge Cognition, 2011), which is one of 22 neuropsychological tests in the Cambridge Neuropsychological Test Automated Battery (CANTAB) eclipse. The two dependent variables utilised in the current study were number of stages completed and number of adjusted errors. A correlation analysis was conducted to analyse the relationship between overselectivity and attention, as well as overselectivity and cognitive flexibility.
Results:
A significant degree of stimulus overselectivity was found in the experimental group using the visual discrimination task. The correlation analysis revealed that overselectivity did not significantly correlate with either of the TEA-Ch subtests that measured selective attention (Subtests 1 and 5), nor attentional switching (Subtests 3 and 8). Although there were no significant correlations between stimulus overselectivity and the sustained attention Subtests 2, 4, 6, and 9, there was a significant correlation with Subtest 7. This finding suggests the possibility that an individual’s ability to self-maintain an actively attentive stance to a given task is correlated with their level of overselective responding. The fact that only one of nine attention subtests was significantly associated with stimulus overselectivity may indicate that the attentional processes under investigation in the current study are not reliable correlates of overselectivity.
In terms of cognitive flexibility, the correlation analysis revealed that neither of the IED dependent variables was significantly associated with levels of overselectivity in both the control and experimental groups. This result indicates that overselective responding is not related to the level of executive function, a finding that supports the findings of Kelly et al. (2016).
Conclusion:
This study offered further evidence of the overselectivity phenomenon by replicating the effect in the current sample of individuals with autism. The novel findings to emerge from this research were that the results from the TEA-Ch and the IED offer experimental evidence contradicting the hypothesis that overselectivity is associated with attention and cognitive flexibility. Replication of the current findings is essential for two reasons. First, the sample was too limited in size. Second, the standardised measures were possibly unsuitable measures for this clinical population as the lower functioning participants had difficulty passing the practice trials and completing the tasks assigned. Further analysis of stimulus overselectivity and its correlates is warranted given its importance when designing behavioral interventions for individuals with autism.
... This view suggests that over-selectivity is not an acquisition, but a performance problemwith some stimuli, although learned about, not controlling behavior because of their relative lack of importance. It has been noted that extinguishing the over-selected stimuli allows the previously under-selected stimuli to control behavior with no additional training, suggesting that the latter were acquired but did not control behavior while the over-selected cues were present Matzel et al. 1985;Reed et al. 2009;Reynolds et al. 2012;Wilkie and Masson 1976). ...
Stimulus over-selectivity describes a phenomenon where only a subset of the relevant stimuli present in the environment, control an individual’s behavior. The current experiment explored the degree to which over-selectivity increases in old age. The level of over-selectivity in a visual discrimination task in 60 individuals aged 60–89 years was assessed, as well as the degree to which this reflected attentional control. In addition, the intellectual functioning and cognitive flexibility of the participants were assessed. Results showed that, as age increased, three effects were revealed: levels of stimulus over-selectivity increased, IQ scores decreased, and cognitive flexibility decreased. However, over-selectivity was not related to IQ or cognitive flexibility, and appeared related most to attentional impairments. Thus, ageing is related to significant declines in effective stimulus control. These effects can have a serious impact on the physical and psychological health of old adults, as well as their quality of life, and, therefore, this area of research warrants further exploration. The results are discussed in relation to the attention-deficit and comparator theory of over-selectivity.
... SLM could thus account for the effects a r t I C l e S of signaling the UUSs with a second CS (the cover-stimulus effect described above) and gave a good fit both for our replication of this phenomenon ( Fig. 5b and Supplementary Fig. 10a) and qualitatively similar predictions to the data from previous studies 28 using related experimental procedures (Supplementary Fig. 10a). The model's prediction for other phenomena (including blocking 10 , overshadowing and recovery from overshadowing 29 ) are further detailed in Supplementary Figure 10b-d. ...
Recognizing predictive relationships is critical for survival, but an understanding of the underlying neural mechanisms remains elusive. In particular, it is unclear how the brain distinguishes predictive relationships from spurious ones when evidence about a relationship is ambiguous, or how it computes predictions given such uncertainty. To better understand this process, we introduced ambiguity into an associative learning task by presenting aversive outcomes both in the presence and in the absence of a predictive cue. Electrophysiological and optogenetic approaches revealed that amygdala neurons directly regulated and tracked the effects of ambiguity on learning. Contrary to established accounts of associative learning, however, interference from competing associations was not required to assess an ambiguous cue-outcome contingency. Instead, animals' behavior was explained by a normative account that evaluates different models of the environment's statistical structure. These findings suggest an alternative view of amygdala circuits in resolving ambiguity during aversive learning.
... The development (or the expression) of a motivation to approach or avoid CS2 is then more difficult. Recovery from the overshadowed CS2 occurs following an extinction of responding to CS1, suggesting that a CS2-UCS was learned but could not express in behaviour (Matzel et al., 1985). As in the case of blocking, extinguishing the motivation for CS1 lowers the ␣-threshold value, allowing the motivation for CS2 to express in behaviour. ...
Learning and motivation are two psychological processes allowing animals to form and express Pavlovian associations between a conditioned stimulus (CS) and an unconditioned stimulus (UCS). However, most models have attempted to capture the mechanisms of learning while neglecting the role that motivation (or incentive salience) may actively play in the expression of behaviour. There is now a body of neurobehavioural evidence showing that incentive salience represents a major determinant of Pavlovian performance. This article presents a motivational model of sign-tracking behaviour whose aim is to explain a wide range of behavioural effects, including those related to partial reinforcement, physiological changes, competition between CSs, and individual differences in responding to a CS. In this model, associative learning is assumed to determine the ability to produce a Pavlovian conditioned response rather than to control the strength and the quality of that response. The model is in keeping with the incentive salience hypothesis and will therefore be discussed in the context of dopamine's role in the brain.
For both humans and machines, the essence of learning is to pinpoint which components in its information processing pipeline are responsible for an error in its output, a challenge that is known as ‘credit assignment’. It has long been assumed that credit assignment is best solved by backpropagation, which is also the foundation of modern machine learning. Here, we set out a fundamentally different principle on credit assignment called ‘prospective configuration’. In prospective configuration, the network first infers the pattern of neural activity that should result from learning, and then the synaptic weights are modified to consolidate the change in neural activity. We demonstrate that this distinct mechanism, in contrast to backpropagation, (1) underlies learning in a well-established family of models of cortical circuits, (2) enables learning that is more efficient and effective in many contexts faced by biological organisms and (3) reproduces surprising patterns of neural activity and behavior observed in diverse human and rat learning experiments.
The authors draw together and develop previous timing models for a broad range of conditioning phenomena to reveal their common conceptual foundations: First, conditioning depends on the learning of the temporal intervals between events and the reciprocals of these intervals, the rates of event occurrence. Second, remembered intervals and rates translate into observed behavior through decision processes whose structure is adapted to noise in the decision variables. The noise and the uncertainties consequent on it have both subjective and objective origins. A third feature of these models is their timescale invariance, which the authors argue is a very important property evident in the available experimental data. This conceptual framework is similar to the psychophysical conceptual framework in which contemporary models of sensory processing are rooted. The authors contrast it with the associative conceptual framework.
Robbins (1988) reported data that he viewed as inconsistent with Miller and Schachtman's (1985a) comparator hypothesis of conditioned response generation. Here we explain why we do not find his experiments a compelling test of the comparator hypothesis. We also briefly review other studies that tested the same predictions of the comparator hypothesis that Robbins examined. We conclude that there is considerable evidence that following excitatory or inhibitory conditioning with a target conditioned stimulus (CS) and unconditioned stimulus (US), extinction of other cues that were present during CS training ordinarily increases excitatory responding and decreases inhibitory responding to the CS. However, consistent with Robbins's conclusion, there is scant evidence that after CS—US training, enhancing the associative value of other cues that were present during CS training influences excitatory or inhibitory responding to the CS. The implications of these conclusions for the comparator hypothesis as an explanation of differences in acquired behavior and as a heuristic tool are considered.
Clothing bias occurs during a showup when the clothing worn by the suspect matches the clothing of the culprit during a crime. The present study investigated whether a clothing match enhanced identification performance at varying levels of culprit facial view. Witnesses watched a mock-crime video and then made an identification decision from a showup. The results indicated that a clothing match led to an increase in correct and false identifications of the suspect, regardless of facial view. However, the presence of a clothing match did not enhance discriminability. Additionally, there was not a match by facial view interaction. Furthermore, there was not calibration of the confidence-accuracy relationship for match or view. The results are discussed in terms of the outshining hypothesis and the legal implications of showup procedures.
Le Grand, Alexis Marie, "An exploration of the impact of clothing match and opportunity to view on showup performance" (2020). Theses. 354. https://louis.uah.edu/uah-theses/354
The dominant view in cognitive psychology is that memory includes several distinct and separate systems including episodic memory, semantic memory and associative learning, each with a different set of representations, explanatory principles and mechanisms. In opposition to that trend, there is a renewed effort to reconcile those distinctions in favour of a cohesive and integrative account of memory. According to instance theory, humans store individual experiences in episodic memory and general-level and semantic knowledge such as categories, word meanings and associations emerge during retrieval. In this Perspective, we review applications of instance theory from the domains of remembering, language and associative learning. We conclude that instance theory is a productive candidate for a general theory of cognition and we propose avenues for future work that extends instance theory into the domain of cognitive computing, builds hybrid instance models and builds bridges to cognitive neuroscience. According to instance theory, semantic knowledge emerges from episodic memories without a distinct semantic memory system. In this Perspective, Jamieson et al. propose instance theory as a general theory of cognition across memory, language and associative learning, and outline future work to extend this approach.
This experiment examined the effects of a redundant cue that predicted the target response to a target stimulus in a response conflict procedure using a flanker task. Participants received trials with five-character arrays with a central target character and distractor flanker characters that matched (compatible) or did not match (incompatible) the central target. Participants’ expectancies for compatible and incompatible trials were manipulated by presenting pre-trial cues that signaled the occurrence of compatible or incompatible trials. Some groups received a single cue predicting the target stimulus and the required target response. Other groups received this cue along with a second redundant, predictive cue. The presence of a second, redundant cue during training in which incompatible trials were predicted facilitated performance (errors were reduced) compared to when only a single cue was present. This finding is consistent with the potentiation effect in conditioning and learning. Extinction of the nontarget cue prior to testing on the target (a retrospective revaluation manipulation) had no effect on performance. The finding of potentiation between pre-trial cues that predict incompatible trials, but not cues that predict compatible trials, suggests that different strategic processes may occur during adaptation to conflict when different kinds of trials are expected.
Because humans live in a dynamic and evolving social world, modeling the factors that guide social behavior has remained a challenge for psychology. In contrast, much progress has been made on understanding some of the more basic elements of human behavior, such as associative learning and memory, which has been successfully modeled in other species. Here we argue that applying an associative learning approach to social behavior can offer valuable insights into the human moral experience. We propose that the basic principles of associative learning—conserved across a range of species—can, in many situations, help to explain seemingly complex human behaviors, including altruistic, cooperative, and selfish acts. We describe examples from the social decision-making literature using Pavlovian learning phenomena (e.g., extinction, cue competition, stimulus generalization) to detail how a history of positive or negative social outcomes influences cognitive and affective mechanisms that shape moral choice. Examining how we might understand social behaviors and their likely reliance on domain-general mechanisms can help to generate testable hypotheses to further understand how social value is learned, represented, and expressed behaviorally.
The phenomenon whereby behavior becomes controlled by one aspect of the environment at the expense of other aspects of the environment (stimulus overselectivity) is widespread across many intellectual and developmental disabilities. However, the theoretical mechanisms underpinning overselectivity are not understood. Given similarities between overselectivity and overshadowing, exploring overselectivity using associative learning paradigms might allow better theoretical understanding of the phenomenon. Three experiments explored overselectivity using a simultaneous discrimination task with typically developing participants undergoing a cognitively demanding task. Experiment 1 investigated whether stimulus duration effects found within the overshadowing literature also occurred in an overselectivity paradigm, and demonstrated that greater overselectivity was observed when stimuli were presented for short durations (2s and 5s) compared with longer durations (10s). Experiment 2 demonstrated that a posttraining revaluation procedure resulted in retrospective revaluation for stimuli presented at shorter durations (2s) and mediated extinction for stimuli presented at longer durations (10s). Such results replicate findings from the overshadowing literature that have been interpreted in terms of within-compound associations while also supporting assumptions made by an extended comparator hypothesis. Experiment 3 uses an additional control condition to further demonstrate that the retrospective revaluation is a genuine revaluation effect. Additionally, the experiment provides further evidence for the within-compound association explanation of the results through manipulating the consistency with which elements of a compound were paired during training. Taken together, the findings highlight the necessity to consider the role of within-compound associations in overselectivity, allowing for a better understanding of overselectivity effects.
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.
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.
Pavlovian conditioning, also known as classical conditioning, is a reliable training procedure that results in an organism responding to a stimulus that previously did not evoke a response. It involves pairing an initially innocuous stimulus, such as a light or tone, with another stimulus that naturally provokes a response, such as food or an electrical shock. The previously neutral stimulus comes to control responding and typically evokes the same behavior that the biologically significant stimulus provoked, albeit weaker. Once a stimulus acquires behavioral control, it is known as a conditioned stimulus (CS) because it required conditioning, or training, to elicit the behavioral response that the unconditioned stimulus (US) naturally evokes. The innate reaction to the US is called the unconditioned response (UR), and the acquired response to the CS is called a conditioned response (CR).
Contemporary theories of associative learning are increasingly complex, which necessitates the use of computational methods to reveal predictions of these models. We argue that comparisons across multiple models in terms of goodness of fit to empirical data from experiments often reveal more about the actual mechanisms of learning and behavior than do simulations of only a single model. Such comparisons are best made when the values of free parameters are discovered through some optimization procedure based on the specific data being fit (e.g., hill climbing), so that the comparisons hinge on the psychological mechanisms assumed by each model rather than being biased by using parameters that differ in quality across models with respect to the data being fit. Statistics like the Bayesian information criterion facilitate comparisons among models that have different numbers of free parameters. These issues are examined using retrospective revaluation data.
Select literature regarding cue competition, the contents of learning, and retrieval processes is summarized to demonstrate parallels and differences between human and nonhuman associative learning. Competition phenomena such as blocking, overshadowing, and relative predictive validity are largely analogous in animal and human learning. In general, strong parallels are found in the associative structures established during learning, as well as in the basic phenomena associated with information retrieval. Some differences arise too, such as retrospective evaluation, which seems easier to observe in human than in nonhuman animals. However, the parallels are sufficient to indicate that the study of learning in animals continues to be relevant to human learning and memory.
Four groups of thirsty rats received training with a compound stimulus (i.e., tone plus light) paired with an unconditioned stimulus (US) during responding for water. Two groups were given additional pairings of A (e.g., tone) and the US (A+) either before (Group A+AX+) or after (Group AX+A+) to AX+ training. Another group received non-reinforced A- presentations after AX+ training, and the remaining group received only AX+ training. Then, all groups were tested for the degree of suppression to X (e.g., light). Although prior conditioning of A attenuated suppression to X (blocking), postconditioning of A enhanced suppression to X. Non-reinforced A presentations after AX+ training had the same effect as AX+ alone. Finally, all groups underwent extinction to A and were tested for suppression to X again. Blocking was preserved in Group A+AX+, but the enhanced suppression to X observed in Group AX+A+ disappeared after extinction of A. These results were accounted for by a within-compound association view.
The effects of extinction of the blocking or overshadowing stimulus on conditioned responding controlled by the blocked or overshadowed stimulus were examined in seven appetitive conditioning experiments with rats. The experiments differed in their designs, stimuli used, the amounts of conditioning and extinction training, and the levels of conditioned responding produced. In all cases, conditioned responding to the blocked or overshadowed cue was either unaffected or reduced by extinction of the blocking or overshadowing cue. These data are consistent with accounts of overshadowing and blocking that attribute those phenomena to acquisition deficits, rather than to retrieval failures.
Rescorla’s “event-memory” hypothesis posits that extinction decrement is due in part to a weakening of a central unconditioned stimulus (US) representation that is shared by all stimuli associated with a particular US. Thus, extinction of one stimulus conditioned to a US should decrease conditioned responding to a second stimulus that has been independently conditioned to the same US. In each of the present experiments, after excitatory conditioning to two stimuli separately, some rats experienced repeated nonreinforced presentations of one of the conditioned stimuli, while others were given no such exposures. Despite parametric variations across experiments, no reliable attenuation of suppression to the nonextinguished stimulus was evident during testing. Tests for suppression to the extinguished stimulus demonstrated a traditional extinction decrement.
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)
Reports 3 experiments employing a conditioned-suppression procedure with male Sprague-Dawley rats (N = 76). In Exp. I and II, initial fear conditioning with a noise UCS was followed by habituation of that UCS. Subsequent testing showed that UCS habituation attenuated the previously established conditioned response. In Exp. III UCS habituation followed the establishment of both a 1st- and a 2nd-order conditioned response. Habituation attenuated the response to the 1st-order, but not to the 2nd-order, stimulus. Implications are noted for the nature of 1st- and 2nd-order conditioning. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Conducted 3 experiments using a conditioned suppression procedure in male Sprague-Dawley rats. Exp I and II (N = 56) found that exposure to a more severe shock either before or after conditioning elevated the CR established by a moderate shock. Exp III (n = 32) found 2nd-order conditioning immune to such modification. These findings parallel earlier results with habituation of the UCS in the absence of the CS. They encourage the view that organisms form memories of the UCS independently of associative connections with the CS. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Gave wavelength-discrimination or discrimination-reversal training to 8 groups of 12 naive domestic pigeons in an operant free-responding paradigm. 4 groups were trained, for 30 min. daily, to criterion. 2 of these groups learned the 2nd (reversal) task in a single continuous session (massed practice), while the 2 others continued with 30-min sessions (distributed practice). 4 control groups experienced only the 2nd discrimination, with either massed or distributed practice. All groups were then tested for generalization either immediately or 24 hr. after reaching criterion on the 2nd task. The reversal had no effect on immediate-test gradients. In the delayed test, however, the massed-practice reversal gradient was flatter and showed less area shift than the others, suggesting a proactive inhibition effect. (21 ref.) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
REPORTS 3 EXPERIMENTS, INVOLVING BOTH INSTRUMENTAL AND CLASSICAL CONDITIONING PROCEDURES IN RATS AND RABBITS. IN EACH CASE A PARTIALLY REINFORCED CUE WAS FOUND TO BE A LESS EFFECTIVE STIMULUS IN ISOLATION WHEN IT HAD BEEN EXPERIENCED AS A COMMON CUE IN COMPOUNDS CONTAINING ELEMENTS MORE HIGHLY CORRELATED WITH REINFORCEMENT, THAN WHEN IT HAD BEEN EXPERIENCED IN SIMILAR COMPOUNDS WHICH DID NOT CONTAIN SUCH ELEMENTS. THE FINDINGS ARE MORE READILY INTERPRETABLE IN TERMS OF THOSE THEORIES WHICH INCORPORATE A BASIC STIMULUS-SELECTION PROCESS, THAN IN TERMS OF SIMPLE CONDITIONING-EXTINCTION THEORY. (17 REF.) (PsycINFO Database Record (c) 2006 APA, all rights reserved).
Pigeons were trained in an operant, go/no-go, discrimination by successive presentations of discrete, positive and negative trials. In separate groups, the rate of discriminaion learning based on an auditory cue, on visual cues of different discriminability, and on combined auditory and visual cues was determined. The auditory cue was tone/no-tone, the visual cue was a difference in brightness level on the key. Following discrimination training, stimulus control was tested in extinction by presenting tone or notone at each of four key-brightness levels.Learning was more rapid with two cues than with either cue singly, demonstrating summation. The contribution made by the tone cue to the learning of the discrimination decreased with increasing discriminability of the light cue. The control exerted by the tone cue also decreased (i.e., the tone cue was overshadowed) with increasing discriminability of the light cue. In certain cases, the tone cue decreased control by brightness, showing that in two-cue discriminations each cue may reduce the control exerted by the other.
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.
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.
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)
In Experiment 1, six groups of pigeons (n=8) were tested for wavelength generalization either immediately or 24 h after learning
a successive discrimination, with 550 nm reinforced and a black vertical line extinguished. The groups differed in the stimulus
present during single stimulus pretraining, which was 550 nm (pretrain S+), the vertical Une (pretrain S−), or a neutral dim
white light (pretrain Sn), respectively. The three immediate generalization gradients were steep and indistinguishable, reflecting
only the immediately preceding discrimination training condition. The three delay gradients were flatter, with the flattening
particularly marked in the pretrain S− group. This was interpreted as proactive interference (PI) resulting from the memory
that both the 550-nm and the line stimuli had previously been reinforced. In Experiment 2, two (TD) groups of pigeons (n=16)
were given single stimulus training with a 555-nm keylight followed by eight sessions of discrimination training with two
line angles, then one session of non-differential (ND) training with the same two lines, and then a wavelength generalization
test either immediately or after a 24-h delay. Two other (hold) groups (n=16) received similar training, except for the TD
Une angle training sessions, in these hold groups, the wavelength gradient was flatter in a delayed test; in the TD groups
it was steeper, indicating PI from the prior TD training. These two experiments suggest that the “attentional sets,” which
purportedly result from TD and ND training, may fruitfully be viewed as target memories subject to the principles of interference
theory.
Three experiments examined the effects of prior extinction with nontarget CSs on a target CS’s rate of extinction and amount
of associative loss. After fear was conditioned to several CSs, rats received extinction training with the target CS either
before or after extinction with nontarget CSs. In general, neither rate of extinction nor amount of associative change, as
measured by reinstatement and relearning, were significantly affected by order of extinction. The present results do not support
Rescorla’s interpretation of extinction.
It was shown that either enhanced or decreased avoidance responding by rats could be produced by the same response blocking procedure occurring after avoidance training. The particular result produced depended on (1) the duration of the blocking trial and (2) when during the retention interval the blocking trial occurred. Results were interpreted in terms of a memory reactivation explanation and implications for the therapeutic uses of extinction were discussed.
Conditioned lick suppression in rats was used to examine the effectiveness of three different “reminder” treatments in reactivating associations to a blocked stimulus in a Kamin blocking paradigm. Experiment I indicated that with our parameters prior tone-footshock pairings could block manifestation of a light-footshock association that would otherwise be evident following pairings of a light-tone compound stimulus with footshock. In Experiment II, exposure to either the US, the blocked stimulus (light), or the apparatus cues between the compound conditioning trials and testing decreased blocking. Experiments III(a) and III(b) replicated the unblocking effects seen in Experiment II and included control groups that received the identical training and reminder treatments except for the omission of the light from the compound stimulus. These latter animals failed to display behaviour comparable to the blocked and reminded subjects, thereby establishing the associative basis of suppression to the light in the animals reminded following treatment known to produce blocking. Experiment IV also replicated the results of Experiment II and included control groups that received identical light-tone compound trials and reminder treatments without prior conditioning to the tone alone. In these control groups, reminder treatments tended to disrupt rather than increase evidence of conditioning to the light. The results suggest that associations are formed to the added element of a compound despite prior conditioning to the initial element, and that failure on the test trial to retrieve these associations to the blocked CS, rather than a failure to attend to or learn about the added element, is at least in part responsible the Kamin blocking effect.
Blocking as a retrieval failure: Reactivation of associations to a blocked stimulus Effect of proactive inhibition upon the post discrimination generalization gradient
- M A Gutsin
- P Cacheiro
- H Miller
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The development of stimulus control through differential reinforcement
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Conditioned reflexes
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Pavlov, I. P, (1927). Conditioned reflexes. London: Oxford Univ. Press.
Simultaneous associations
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RescorIa, R. A. (1981). Simultaneous associations. In P. Harzem & M. D, Zeiler (Eds.), Predictability, correlation, and contiguity (pp. 47-80). Chichester, United Kingdom: Wiley.
The comparator hypothesis of conditioned response generation: Mantfest conditioned ex-citation and inhibition as u function of differences in excitatory associative strength of CS und context
- W J Kasprow
- L D Matzel
- L Gladstein
- L Feldman
- R R Miller
Kasprow, W. J., Matzel, L. D., Gladstein, L., Feldman, L., & Miller, R. R. (1985). The comparator hypothesis of conditioned response generation: Mantfest conditioned ex-citation and inhibition as u function of differences in excitatory associative strength of CS und context. Manuscript submitted for publication.