-1- The Relevance of Relevance in Children's Cognition. Agnes Blaye University of Aix-Marseille 1, France Edith Ackermann University of Aix-Marseille 1, France, and MERL - A Mitsubishi Electric Research Laboratory, USA Paul Light Bournemouth University, UK Abstract Current research in cognitive development shows that people’s reasoning and decision- making strategies are deeply grounded in contexts of use. They are situated and thus cannot, as many developmentalists have it be gauged according to logical criteria alone. Two broad empirical approaches can be used to study children’s embodied thinking. On the one hand, we have ethological studies which preserve the complexity and “naturalness” of the settings in which people dwell, on the other, variations on classical laboratory experiments can be proposed to highlight the discrepancy between logical and pragmatic constraints. Following this second approach, we will consider three aspects of children's growing reasoning capabilities: conditional reasoning, categorization, and the comprehension of negative sentences. In each of these fields, the authors revisit some of the ‘mainstream topics’ in cognitive development, with the idea in mind that a pragmatically grounded 'rationality of purpose' might be more characteristic of children's thinking than 'rationality of process'. Authors’ own research brings strong empirical evidence to the currently held idea that children's thinking is far more flexible and better adapted than would be supposed on the basis of a Piagetian account of the development of operational thinking In “learning Sites: Social and Technological Resources for Learning,” (J. Bliss, P.Light, & R. Saljo, Eds.). Pergamon Elsevier Serie: Advances in Learning and Instruction, 1999. pp. 120-132