Trust modelling is a challenging issue due to the dynamic nature of distributed systems and the unreliability of self-interested agents. In this context, the Agent Reputation and Trust (ART) Testbed has been used to compare trust models in two Spanish competitions in 2006 and 2007 and several international competitions. In this paper we describe the model we have presented to the Spanish competitions. We propose a trust model that uses the discrepancy between the information provided by other

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... ents and its own experience in order to anticipate their actions, instead of using that discrepancy as a source of dishonesty and distrust. In addition we propose a cognitive model based on motivational attitudes to implement adaptive behaviors. Various implementations of this trust model have participated in the competitions; one was the winner of the first Spanish competition in 2006, the other won a combined game that included the participants in the two Spanish competitions.