El acceso a la versión del editor puede requerir la suscripción del recurso Access to the published version may require subscription 1 Rosa, A. & Valsiner, J. (Eds.). Cambridge Handbook of Sociocultural Psychology (2nd Ed.

The modeling of epistemic knowledge is a necessity of most systems dealing with some sort of artificial reasoning. There a r e several formalisms able to mathematically model someone's degrees of belief. A very popular one is the Bayesian Theory, which is based on a prior knowledge of a probability distribution. Another model is the Theory of Evidence, or DempskrShafer Theory, which provides a method for combining evidences from different sources without prior knowledge of their distributions. In this latter method, it is possible to assign probability values to sets of possibilities rather than to single events only, and it is not needed to divide all the probability values among the events, once the remaining probability should be assigned to the environment and not to the remaining events, thus modeling more naturally certain classes of problems. There are some pitfalls however, in particular, the Dempster-Shafer Theory does not model well evidences with a high degree of conflict, and evidences with the more probable possibility disjoint but with a less probable possibility in common tend to bias the results bward the less probable hypothesis in an illogical way, assigning 100% probability to it.In this paper we present an extension of DempsterShafer Theory that overcome the afore mentioned pitfalls, allowing the combination of evidences with higher degrees of conflict, and avoiding the excessive tendency toward the common possibility of otherwise disjoint hypothesis. This is accomplished by means of a new rule of evidences combination that embodies the conflict among the evidences, modeling naturally the epistemic reasoning.

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Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/riya20Quantification and use of numerical information up to two units in three-to four-year-old children / Cuantificación y uso de informaciones numéricas hasta dos unidades en niños de tres a cuatro años

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We investigated the process through which children understand the conventional use of numbers in interaction with an adult. We analysed previous semiotic systems that support, transform and adjust to this new semiotic system — the numerical — and we investigated the communicative-educative basis that makes it possible. We conducted an exploratory and longitudinal study with one boy and one girl at 24, 27, 30, 33 and 36 months of age in a triadic interaction (adult-child-object) with their mothers at home. We adopt the pragmatic-semiotic perspective of the object, which considers that triadic interactions are the unit of analysis of early development. Our results show a great variety of semiotic mediators used by children and adults and both children’s progressive comprehension of the meaning and use of the die as a numerical object.

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