Abstract EN:

Adults' basic perceptual blases question linear and cumulative conceptions of cognitive development (like Piaget's) that consider adults to be radically différent from children. Thèse biases indicate indeed that our behaviour is often guided by heuristic stratégies which may be adaptive or not depending on situations and which coexist with other, more analytic stratégies. Hère, thé overall aim is to identify neurocognitive mechanisms underlying young adults' ability to overcome such biases during logico-mathematical tasks. Our first study, using functional Magnetic Résonance Imaging, shows that thé « lengfh-equals-number » strategy that accounts for children's failure on Piaget's conservation of number task (until 7-years-old) persists in adults. Results indicate that adults overcome thé interférence induced by this strategy by recruiting an executive prefrontal network involved in conflict monitoring. They also use stratégie adjustments characterized by an interindividual variability présent both at thé behavioural and neural levels. Some subjects rely on a counting strategy and recruit a leftward asymmetric network, while others use a visuospatial strategy associated with a network showing a rightward asymmetry. The second study consists in a training paradigm based on two logically isomorphic tasks of deductive reasoning. Results show that adults' ability to correct a robust matching bias relies on inhibitory and metacognitive factors. It is also associated with a somatic state indexed by an increase of Skin Conductance Response.