Equilibria of the Rescorla-Wagner model

The Rescorla-Wagner model has been a leading theory of animal causal induction for nearly 30 years, and human causal induction for the past 15 years. Recent theories (especially Psychol. Rev. 104 (1997) 367) have provided alternative explanations of how people draw causal conclusions from covariational data. However, theoretical attempts to compare the Rescorla-Wagner model with more recent models have been hampered by the fact that the Rescorla-Wagner model is an algorithmic theory, while the more recent theories are all computational. This paper provides a detailed derivation of the long-run behavior of the Rescorla-Wagner model under a wide range of parameters and experimental setups, so that the model can be compared with computational theories. It also shows that the model agrees with competing theories on a wider range of cases than had previously been thought. The paper concludes by showing how recently suggested modifications of the Rescorla-Wagner model impact the long-run behavior of the model.     

Teaching the Rescorla-Wagner model using STELLA-II

Although the Rescorla-Wagner model is widely taught in learning courses, most textbooks present a simplified version that does not contain all of its parameters. On the basis of Rescorla and Wagner 1972) and the Turbo PASCAL program by Lachnit, Schneider, Lipp, and Kimme! (1988), we created a simulation using STELLA-II, an icon-based program by High Performance Systems, Inc. We argue that this simulation facilitates teaching the complete Rescorla-Wagner model. Using trans-switching (Kimmel & Ray, 1978; Lachnit, 1986; Murrin & Kimmel, 1986) as an example, we demonstrate the effectiveness of the STELLA-II version of the Rescorla-Wagner model as a heuristic tool.     

New methods for solving the Rescorla-Wagner model

Two new methods for generating predictions from the Rescorla-Wagner model are presented. One is to solve the simultaneous equations of the model as differential equations, and the other is to solve them as difference equations, by using recent computer software. The model has been described in terms of simultaneous difference equations, and its predictions have traditionally been derived by performing an iterative computer simulation. But the limit can be taken, and the model can be considered in terms of simultaneous differential equations. Computer software, such as Mathematica and Maple, can solve simultaneous differential or difference equations. The author shows how to use Mathematica for some experimental paradigms, from simple acquisition to more complex cue competition paradigms, and also explains the rule for constructing input. The relative merits of these methods and of simulation are discussed.     

RWMODEL II: computer simulation of the Rescorla-Wagner model of Pavlovian conditioning

RWMODEL II simulates the Rescorla-Wagner model of Pavlovian conditioning. It is written in Delphi and runs under Windows 3.1 and Windows 95. The program was designed for novice and expert users and can be employed in teaching, as well as in research. It is user friendly and requires a minimal level of computer literacy but is sufficiently flexible to permit a wide range of simulations. It allows the display of empirical data, against which predictions from the model can be validated.     

The Rescorla-Wagner model: losses in associative strength in compound conditioned stimuli

This series of experiments demonstrated that compound conditioned stimuli (CSs) highly conditioned in isolation lose conditioned response strength when compound-CS-unconditioned stimulus (US) pairings are given. This loss in conditioned responding was a positive function of the number of compound-CS-US pairings and was greater for the more salient stimulus. Finally, if a previously neutral stimulus was compounded with two previously conditioned cues, the neutral stimulus could acquire conditioned inhibitory properties with only compound-CS-US pairings. These results provide support for some aspects of the Rescorla-Wagner model.     

Application of the new method for the Rescorla-Wagner model to a probabilistic learning situation

The author recently showed that it is not always necessary to perform simulations to derive predictions from the Rescorla-Wagner model, and presented an alternative method. In this article, the method is applied to an influential experimental paradigm: base-rate neglect.     

Odor as a conditioned inhibitor: Applicability of the Rescorla-Wagner model to feeding behavior

Hooded rats were given conditioned inhibition training in which the taste of saccharin alone was always followed by induced illness, but the taste of saccharin plus the odor of amyl acetate was not. In a series of three subsequent tests—summation, enhancement of conditioning, and retardation—it was demonstrated that the odor had acquired active inhibitory properties. The results paralleled those obtained with more traditionally studied stimuli and techniques and hence were found to be readily predictable from a recent model of conditioning set forth by Rescorla and Wagner (1972).     

Conditioned inhibition is not the symmetrical opposite of conditioned excitation: A test of the Rescorla-Wagner model

Rescorla and Wagner's (1972) linear associative model of learning predicts that a neutral stimulus will become weakly excitatory if it is paired with a conditioned inhibitor and the compound is not reinforced. If the inhibitor is not allowed to extinguish during these pairings, the model predicts that the neutral stimulus will become strongly excitatory. Rescorla (1971) has presented some evidence to support the former prediction of a weak effect. Experiment I tested the latter prediction of a strong effect using rats in a conditioned emotional response paradigm, and found no evidence that the pairings made the neutral stimulus excitatory. Experiment II replicated Rescorla's results, but showed that even on a relearning test the experimental group learned no faster than a novel stimulus control group.     

A way to install conditioned modulation in the Rescorla-Wagner Axiom: The amplifier model of Pavlovian conditioning (AMP)

Although the Rescorla-Wagner axiom has been successful in explaining and predicting many phenomena in Pavlovian conditioning, it offers no explanation for the ability of stimuli to modulate conditioned responding to other stimuli (i.e., the occasion-setting effect). This article provides a mathematical model for Pavlovian conditioned modulation by adding simple rules to the Rescorla-Wagner axiom. In spite of its rudimentary stage, the proposed model can explain many of the basic findings of modulatory learning and suggests some new areas of research.     

RWMODEL: A program in Turbo Pascal for simulating predictions based on the Rescorla-Wagner model of classical conditioning

A Turbo Pascal computer program is described that simulates the Rescorla-Wagner model of classical conditioning. The menu-driven program makes it possible to compute associative strengths for differential conditioning, conditioned inhibition, compound and contextual conditionings, trans-switching, and other designs.     

Computer simulations of the Rescorla-Wagner and Pearce-Hall models in conditioning and contingency judgment

A Visual BASIC program, running under Windows 3.1, simulated the predictions of the Rescorla—Wagner (Rescorla & Wagner, 1972) and the Pearce-Hall (Pearce & Hall, 1980) models and compared them to the normative contingency coefficient ΔP (Jenkins & Ward, 1965). The simulations can be applied to a variety of phenomena in human contingency judgment as well as learning and conditioning. Possible simulations include acquisition and extinction of excitatory and inhibitory conditioning, latent inhibition, blocking and overshadowing, or any other associative learning involving two single predictors, their compound, a contextual stimulus, and an outcome. The Pearce-Hall model has never been computerized before. In addition, unique features of this software include extensive use of the graphic user interface, context-sensitive help, verification of trial combinations, toggling of the contextual stimulus from ever-present to mutually exclusive with the discrete predictors, data entry via contingency tables or specifications trial by trial, single or batch randomizations of trial order, and specification of initial values. The associative simulator is both a powerful scientific instrument and a user-friendly teaching aid.     

The influence of trait affect and the five-factor personality model on impulse buying

Research into the influence of affect on impulse buying has to date produced contradictory results, partly due to confusion between the potentially discrete influences of, respectively, state and trait affect. Additionally, studies on how the five-factor personality model’s dimensions influence impulse buying have also produced contradictory results. Moreover, while the established link between trait affect and personality suggests dimensions of this latter could account for whatever influence the former has on impulse buying, no study has yet attempted to examine this possibility. We draw on self-regulation theory to examine three unanswered questions: (1) the extent to which trait affect influences impulse buying whilst controlling for state affect; (2) establish which dimensions of the five-factor personality model predict impulse buying; and (3) test whether or not any influence of trait affect on impulse buying is additive to the effects of the five-factor personality model. Analyses of cross-sectional data (n = 842) find that trait affect does have a significant (p < .05) influence on impulse buying controlling for state affect, but that this influence is fully accounted for by the five-factor personality model (p < .001), the extraversion, conscientiousness and neuroticism dimensions of which are found consistently to predict impulse buying.     

Learning and motivation: Computer simulations of the Rescorla-Wagner,Solomon-Corbit,and Schull models

A suite of programs is described for simulating the Rescorla-Wagner (1972) model of associative learning, the Solomon and Corbit (1974) opponent-process theory, and Schull’s (1979) extension of the latter. The programs are written for the Commodore 64 computer.     

Assessing the influence of dimensional focus during situation model construction

According to Zwaan, Langston, and Graesser's (1995) event-indexing model, when comprehending text, readers monitor changes in a series of critical dimensions: space, time, protagonist, causality, and intentionality. In this study, the influence of dimensional focus was assessed during situation-model construction. Participants read narratives and were instructed to specifically monitor a single dimension while their sentence reading times were recorded. Critical sentence reading times were then analyzed for all shift types. Results support the general prediction that at least the time and protagonist dimensions are resistant to task demands, demonstrating that comprehenders routinely perform dimensional updating processes that are context independent. These results are discussed in the context of the event-indexing model.     

The ethics of biometrics: the risk of social exclusion from the widespread use of electronic identification

Discussions about biotechnology tend to assume that it is something to do with genetics or manipulating biological processes in some way. However, the field of biometrics-the measurement of physical characteristics-is also biotechnology and is likely to affect the lives of more people more quickly than any other form. The possibility of social exclusion resulting from the use of biometrics data for such uses as identity cards has not yet been fully explored. Social exclusion is unethical, as it unfairly discriminates against individuals or classes of people. Social exclusion is unethical, as it unfairly discriminates against individuals or classes of people. This article looks at some of the ways in which social exclusion might arise from the use of biometric data, and introduces a model of balancing individual interests with which to analyse whether it is justified to run the risk of excluding some members of society for the benefit of others.     

Developmental dyslexia and widespread activation across the cerebellar hemispheres

Developmental dyslexia is the most common learning disability in school-aged children with an estimated incidence of five to ten percent. The cause and pathophysiological substrate of this developmental disorder is unclear. Recently, a possible involvement of the cerebellum in the pathogenesis of dyslexia has been postulated. In this study, 15 dyslexic children and 7 age-matched control subjects were investigated by means of functional neuroimaging (fMRI) using a noun-verb association paradigm. Comparison of activation patterns between dyslexic and control subjects revealed distinct and significant differences in cerebral and cerebellar activation. Control subjects showed bilaterally well-defined and focal activation patterns in the frontal and parietal lobes and the posterior regions of the cerebellar hemispheres. The dyslexic children, however, presented widespread and diffuse activations on the cerebral and cerebellar level. Cerebral activations were found in frontal, parietal, temporal and occipital regions. Activations in the cerebellum were found predominantly in the cerebellar cortex, including Crus I, Crus II, hemispheric lobule VI, VII and vermal lobules I, II, III, IV and VII. This preliminary study is the first to reveal a significant difference in cerebellar functioning between dyslexic children and controls during a semantic association task. As a result, we propose a new hypothesis regarding the pathophysiological mechanisms of developmental dyslexia. Given the sites of activation in the cerebellum in the dyslexic group, a defect of the intra-cerebellar distribution of activity is suspected, suggesting a disorder of the processing or transfer of information within the cerebellar cortex.     

The influence of response conflict on voluntary task switching: a novel test of the conflict monitoring model

The conflict monitoring model of cognitive control posits that response conflict triggers a top-down enhancement of a task’s representation in working memory. In the present study, we conducted a novel test of the conflict monitoring model using a voluntary task switching paradigm. We predicted that a task’s representation would be enhanced following events associated with high response conflict (i.e., incongruent trials and incorrect responses), leading participants to voluntarily choose to repeat that task more often after these events than after events associated with low response conflict (i.e., congruent trials and correct responses). In two experiments, performance following incongruent trials was consistent with the conflict monitoring model. However, performance following incorrect trials did not fit with the model’s predictions. These findings provide novel support for the conflict monitoring model while revealing new effects of incorrect trials that the model cannot explain.     

Attachment,the tripartite influence model,and the development of body dissatisfaction

The tripartite model of influence proposes that three primary core sources of influence-parents, peers and media-contribute to the development of body dissatisfaction and disordered eating. In the current study, this model was examined in a sample of 205 undergraduate women. This study added to previous research by investigating mother and father criticism separately and by examining the potential moderating effects of parental attachment in the pathway to body dissatisfaction. Results indicated partial support for the tripartite model of influence. Sociocultural influences (media) were found to be a significant predictor of body dissatisfaction, but not parental or peer criticism. Anxious attachment was found to be a significant moderator on the effects of sociocultural attitudes in body dissatisfaction. Limitations and future research implications are discussed.