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.     

Lois de la Nature et Constructions de l'Esprit

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Scientists’ Argumentative Reasoning

Reasoning, defined as the production and evaluation of reasons, is a central process in science. The dominant view of reasoning, both in the psychology of reasoning and in the psychology of science, is of a mechanism with an asocial function: bettering the beliefs of the lone reasoner. Many observations, however, are difficult to reconcile with this view of reasoning; in particular, reasoning systematically searches for reasons that support the reasoner’s initial beliefs, and it only evaluates these reasons cursorily. By contrast, reasoners are well able to evaluate others’ reasons: accepting strong arguments and rejecting weak ones. The argumentative theory of reasoning accounts for these traits of reasoning by postulating that the evolved function of reasoning is to argue: to find arguments to convince others and to change one’s mind when confronted with good arguments. Scientific reasoning, however, is often described as being at odds with such an argumentative mechanisms: scientists are supposed to reason objectively on their own, and to be pigheaded when their theories are challenged, even by good arguments. In this article, we review evidence showing that scientists, when reasoning, are subject to the same biases as are lay people while being able to change their mind when confronted with good arguments. We conclude that the argumentative theory of reasoning explains well key features of scientists’ reasoning and that differences in the way scientists and laypeople reason result from the institutional framework of science.     

Manipulation of the apparatus and response context may reduce the US pre-exposure interference effect

In two experiments, we investigated whether manipulations of associations formed between the context and unconditioned stimulus (US) during exposure would reduce the retardation of future conditioning produced by exposure to the US. In the first experiment, we found that extinguishing the context reduced fear of the context and partially attenuated interference with future conditioning. This attenuation was only transient and there was considerable interference which was unaffected by extinction. In the second experiment, we found that signalling the US during pre-exposure which was carried out off-baseline did not reduce interference when conditioning was also carried out off-baseline. However, signalling the US did reduce interference when conditioning was subsequently continued on-baseline. These results suggest that although the US interference effect is partly mediated by conditioning of the context, it may also depend on learning about the unpredictability of the US during exposure, and some long-term, perhaps context specific, adaption-like mechanism.     

Juvenile vervet monkeys rely on others when responding to danger

Animal Cognition - Primate alarm calls are mainly hardwired but individuals need to adapt their calling behaviours according to the situation. Such learning necessitates recognising locally...