Associative Change in the Representations Acquired During Conditional Discriminations: Further Analysis of the Nature of Conditional Learning.

Three experiments with rats investigated how the associative strengths of the representations that underlie conditional learning change when they are conditioned in compound. The results of each experiment suggest that the representation whose associative strength is most discrepant from the asymptote supported by the outcome of the trial undergoes the greatest change in associative strength. These results parallel those from simple Pavlovian conditioning (e.g., R. A. Rescorla, 2000). are inconsistent with unique-cue and configural accounts of conditional learning, and support a connectionist analysis of learning in which a "winner-takes-all" rule applies to the hidden units that can be activated and acquire associative strength at a given point in time. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Dissociations between expectancy and performance in simple and two-choice reaction-time tasks: A test of associative and nonassociative explanations.

Perruchet, Cleeremans, and Destrebecqz (2006) reported a striking dissociation between trends in the conscious expectancy of an event and the speed of a response that is cued by that event. They argued that this indicates the operation of independent processes in human associative learning. However, there remains a strong possibility that this dissociation is not a consequence of associative learning and is instead caused by changes in vigilance or sensitivity based on the recency of events on previous trials. Three experiments tested this possibility with versions of a cued reaction time task in which trends in performance could not be explained by these nonassociative factors. Experiment 1 introduced a dual-response version of the task, in which response-related vigilance should be held relatively constant, and Experiments 2 and 3 used a differential conditioning procedure to separate the influence of recent response cue presentation from the recent associative history of the trial events. In all experiments, similar trends in reaction time were evident, suggesting a genuine influence of associative learning on response performance. Experiment 3 demonstrated that the associative contribution to these trends was not caused by commensurate changes in expectancy of the response cue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blocking and Unblocking in Human Causal Learning.

Three experiments sought to develop the suggestion that, under some circumstances, common associative learning mechanisms might underlie animal conditioning and human causal learning, by demonstrating, in humans, an effect analogous to the unblocking by reinforcer omission observed in animal conditioning. Experiment 1 found no such effect. Experiment 2, designed to prevent inhibitory influences that might have masked excitatory unblocking in Experiment 1, demonstrated unblocking, indicating common human-animal associative learning mechanisms in which the associability of a stimulus varies as a function of its predictive history. Experiment 3, using a similar design but with a procedure promoting application of rational inference processes, failed to detect the same unblocking effect, indicating that associative and cognitive mechanisms may influence human causal learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reasoning rats: Forward blocking in Pavlovian animal conditioning is sensitive to constraints of causal inference.

Forward blocking is one of the best-documented phenomena in Pavlovian animal conditioning. According to contemporary associative learning theories, forward blocking arises directly from the hardwired basic learning rules that govern the acquisition or expression of associations. Contrary to this view, here the authors demonstrate that blocking in rats is flexible and sensitive to constraints of causal inference, such as violation of additivity and ceiling considerations. This suggests that complex cognitive processes akin to causal inferential reasoning are involved in a well-established Pavlovian animal conditioning phenomenon commonly attributed to the operation of basic associative processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Outcome Specificity of Learned Predictiveness Effects: Parallels Between Human Causal Learning and Animal Conditioning.

Two experiments examined the outcome specificity of a learned predictiveness effect in human causal learning. Experiment 1 indicated that prior experience of a cue-outcome relation modulates learning about that cue with respect to a different outcome from the same affective class but not with respect to an outcome from a different affective class. Experiment 2 ruled out an interpretation of this effect in terms of context specificity. These results indicate that learned predictiveness effects in human causal learning index an associability that is specific to a particular class of outcomes. Moreover, they mirror demonstrations of the reinforcer specificity of analogous effects in animal conditioning, supporting the suggestion that, under some circumstances, human causal learning and animal conditioning reflect the operation of common associative mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypotheses and habits in verbal "operant conditioning.'

The traditional explanation of experiments related to conditioning of verbal behavior in terms of operant conditioning, i.e., learning without awareness, was questioned. It was hypothesized that such conditioning to cues given by E might be based on S's awareness of the cue and assumed meaning of such a stimulus. 2 experiments were performed, 1 where plural nouns were reinforced, and a 2nd to test the generalization of this acquired pattern on a word association test. The usual findings re: conditioning of plural nouns was replicated and there seemed to be a carry-over of the set to the word association test. However, some Ss seemed to be aware of the meaning of such a reinforcer as "um-hm." Moreover, response set was also seen to affect conditionability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context specificity of conditioning, extinction, and latent inhibition.

Three experiments, using a conditioned suppression procedure with 112 male hooded Lister rats, examined the mechanisms of context specificity of conditioning, extinction, and latent inhibition. Exp I replicated previous demonstrations of context specificity of conditioning and extinction. Conditioning in one context did not necessarily transfer perfectly to another, and if extinction was carried out in a context different from that of conditioning, Ss showed a recovery of suppression when tested in the conditioning context. But both of these results disappeared when the familiarity and associative values of the 2 contexts were equated. Exp II replicated this failure to obtain context specificity of conditioning and extinction, but it did obtain context specificity of latent inhibition. Ss preexposed and conditioned to stimuli in the same context showed more profound latent inhibition than those preexposed and conditioned in different contexts. In Exp III, this effect was replicated. It is concluded that context specificity of conditioning or extinction may arise from the failure to control the associative status of the contexts used, whereas that of latent inhibition can best be explained by A. R. Wagner's (1976, 1981) theory of associative learning. Results offer no support for the view that, under conditions such as these, contexts serve as conditional cues, signaling the relationships between events occurring in their presence. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are associative changes in acquisition and extinction negatively accelerated?

Performance to a conditioned stimulus typically shows a negatively accelerated change with Pavlovian conditioning or extinction. This is commonly attributed to negatively accelerated changes in the underlying associative learning. However, the absence of well-specified rules for mapping learning into performance makes it difficult to infer changes in the size of associative changes for stimuli occupying different points on the performance scale. This problem can be addressed by comparing responding to stimulus compounds, each consisting of 2 stimuli, 1 of which is poorly conditioned and 1 of which is well conditioned, when either the former or the latter receives a specified amount of additional training. This permits comparison at a common performance level. Two magazine-approach experiments in rats and 2 autoshaping experiments in pigeons used this technique to assess the form of the associative changes in acquisition and extinction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Ontogeny of Human Learning in Delay, Long-Delay, and Trace Eyeblink Conditioning.

The ontogeny of associative learning in delay (750-ms conditional stimulus [CS], 650-ms interstimulus interval [ISI]), long-delay (1,350-ms CS, 1,250-ms ISI), and trace (750-ms CS, 500-ms trace interval, 1,250-ms ISI) eyeblink conditioning was examined in 5-month-old human infants and adults. Infants and adults showed different acquisition rates but reached equivalent asymptotes of conditional responses (CRs) in standard delay conditioning. In long-delay and trace conditions, infants exhibited less robust conditioning than adults and minimal ability to appropriately time CRs. During infancy, the ISI, rather than the conditioning procedure, predicted rate and effectiveness of CRs. These findings suggest that higher order cognitive abilities begin emerging early in development. Across ontogeny, however, there are changes in the limits and parameters that support associative learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

UCS intensity and performance in eyelid conditioning.

Studies of the effects of UCS intensity on performance in human eyelid conditioning are reviewed, particularly with respect to a recent claim that this variable determines the proportion of Ss who condition and not the performance level of individual Ss. The evidence reviewed clearly indicates that UCS intensity does affect the level of performance in Ss who condition. The function involved appears to be negatively accelerated and to approach an asymptote within a relatively small range of intensity values. These effects of UCS intensity are interpreted as reflecting both motivational and associative factors. (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Argument strength, delay of argument, and anxiety in the "conditioning" and "selective learning" of attitudes.

Attitude learning through persuasive communication was studied in 2 experimental situations regarded as being analogous to instrumental conditioning and selective learning, respectively. The communications, which the originally neutral Ss read aloud, included a statement of the opinion to be learned followed by some supporting information (the argument) which did not repeat the opinion statement. Experiment I (2 X 2 factorial, N = 363) results were: speed (1/latency) of agreement with a statement of the opinion was an increasing function of argument strength and drive (MA scale), with argument strength and anxiety combining additively to determine speed of agreement. In Experiment II, 2 separate and unrelated opinions were persuaded for each S (N = 48), and Ss were then required to choose between the 2 opinions in a simultaneous presentation situation. The Ss learned to choose the opinion which was persuaded with the shorter delay of argument (time between opinion statement and argument), and this tendency was inversely related to drive. The results were predicted by a theory of persuasion based on analogies with learning research and Hullian learning theory. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facilitation of extinction by an increase or a decrease in trial duration.

Five experiments examined the effects of altering the duration of a conditioned stimulus (CS) for extinction. For the first 3 experiments, rats received conditioning with a 10-s CS before different groups received extinction with a CS that was either the same duration or longer than that used for conditioning. For the remaining 2 experiments, conditioning was conducted with a 60-s CS before different groups received extinction with a CS of either the same duration or a shorter duration than that used for conditioning. In all experiments, extinction progressed more readily when the CS duration was different for the 2 stages than when it was constant. The results are discussed in terms of rate expectancy theory and associative learning theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nicotine enhances context learning but not context-shock associative learning.

Nicotine has been found to enhance learning in a variety of tasks, including contextual fear conditioning. During contextual fear conditioning animals have to learn the context and associate the context with an unconditioned stimulus (footshock). As both of these types of learning co-occur during fear conditioning, it is not clear whether nicotine enhances one or both of these types of learning. To tease these two forms of learning apart, the authors made use of the context preexposure facilitation effect (CPFE). Acquisition of the CPFE requires that contextual and context-shock learning occurs on separate days, allowing for their individual manipulation. Nicotine (0.09 mg/kg) administered prior to contextual learning and retrieval enhanced the CPFE whereas administration prior to context-shock learning and retrieval had no effect. Thus, nicotine enhances contextual learning but not context-shock associative learning. Finally, the results are discussed in terms of a theory of how nicotine could alter hippocampal-cortical-amygdala interactions to facilitate contextual learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of Healthy Aging on Awareness and Fear Conditioning.

Fear conditioning has provided a useful model system for studying associative emotional learning, but the impact of healthy aging has gone relatively unexplored. The present study investigated fear conditioning across the adult life span in humans. A delay discrimination task was employed using visual conditioned stimuli and an auditory unconditioned stimulus. Awareness of the reinforcement contingencies was assessed in a postexperimental interview. Compared with young adult participants, middle-aged and older adults displayed reductions in unconditioned responding, discriminant conditioning, and contingency awareness. When awareness and overall arousability were taken into consideration, there were no residual effects of aging on conditioning. These results highlight the importance of considering the influence of declarative knowledge when interpreting age-associated changes in discriminative conditioned learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal conditioning as a function of experimenter characteristics.

An investigation was conducted to test the hypothesis that differences in the characteristics of experimenters can lead to differential learning effects when the experimental session involves verbal conditioning without awareness. "Two experimenters of different sex and markedly different height, weight, age, appearance, and personality ran separate groups of Ss." Results indicated that "the response 'Good' was reinforcing for the class of behavior consisting of the use of hostile words in sentences. In addition, it was found that the rates of learning for the Ss of the two experimenters differed significantly, with a steeper slope for the female experimenter's group." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Configural" conditioning in discrete-trial bar pressing.

Conducted 3 experiments with a total of 64 male Sprague-Dawley rats to compare responses to stimulus compounds and their elements. No loss was found when Ss responded to the elements of a repeatedly reinforced stimulus compound. When Ss were explicitly trained to discriminate between a compound and its elements, successful learning occurred regardless of whether the compound or the elements were reinforced. Addition of an explicit stimulus common to the compound and its elements retarded rather than facilitated the discrimination. Replacement of 1 element in a compound by another of similar intensity and associative strength disrupted performance. Findings rule out a number of interpretations of AB configural conditioning paradigms, but suggest that there is a unique stimulus element and limitations on the total associative strength of the compound. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of UCS preexposure on excitatory and inhibitory rabbit eyelid conditioning: An associative effect of conditioned contextual stimuli.

Preconditioning experience with the UCS retards subsequent excitatory conditioning. Three experiments demonstrated that the UCS retardation effect is attenuated by associative manipulations of contextual stimuli of the UCS preexposure environment. The UCS retardation effect was reduced by (a) altering contextual stimuli between preexposure and conditioning (Exp I, 49 New Zealand male rabbits; Exp II, 28 Ss); and (b) latently inhibiting contextual stimuli subsequent to UCS (Exp III, 36 Ss). Although UCS preexposure retarded excitatory conditioning, results of Exp IV (48 Ss) demonstrated that UCS preexposure facilitated inhibitory conditioning. Overall findings indicate that an association between contextual stimuli and preexposed UCS contributes to the effects of preconditioning UCS experience on subsequent learning. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear, Conditioning, and Aging: Theoretical Comment on LaBar et al. (2004).

Age-related impairments in associative learning have been found in studies using classical conditioning of motor responses. However, it is as yet unclear whether conditioning of fear responses is similarly affected by aging. K. S. La Bar et al. (2004; see record 2004-19432-004) aimed to address this issue by studying age effects on fear conditioning applying a discrimination paradigm. Considering these results, this commentary discusses methodological issues in investigating fear conditioning as well as similarities and differences between associative learning of motor and autonomic responses with respect to neuronal substrates, susceptibility to aging, and the role of awareness of stimulus contingencies in mediating aging effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation of excitatory and inhibitory associations between absent events.

Considerable evidence indicates that associations may be formed between two events even when one or both of them is absent at the time of learning. Previously, some researchers asserted that excitatory associations are formed when associatively activated representations for two events are paired, whereas others claimed that inhibitory associations are formed. In three experiments, the authors investigated the nature of tone-sucrose learning when associatively activated representations of those events were paired in the absence of either of the events themselves. Experiment 1 found substantial excitatory learning when the tone surrogate preceded the sucrose surrogate in training. Experiment 2 evaluated other accounts for the results of Experiment 1, and Experiment 3 found evidence for inhibitory tone-sucrose learning when the tone and sucrose surrogates were presented in simultaneous or backward order. The results indicated that the nature of representation-mediated learning is influenced by some of the same variables as more standard associative learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mediation and associative facilitation in neurotic, psychotic, and normal subjects.

The present investigation is a replication of previous work (see 30: 555; 27: 4925) utilizing Veterans Administration medical and psychiatric patients instead of college Ss. The previous findings indicated that associative relationship facilitates verbal learning. Ss learned 2 sets of syllable-word paired associates; ? of the pairs on the 2nd list had response terms which were associates of their responses to words on the 1st list. Although the responses of all Ss showed the effects of associative facilitation, this was more true for nonpsychotics. The results are discussed in terms of understanding the thinking of schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)