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RESEARCH PRODUCT

Le traitement des expressions faciales au cours de la première année : développement et rôle de l'olfaction

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The first year of life is critical for the development of the abilities to process facial expressions. Olfaction and expressions are both strongly linked to each other, and it is well known that infants are able to multisensorially integrate their environment as early as birth. However, most of the studies interested in multisensory processing of facial expressions are restricted to the investigation of audio-visual interactions.In this thesis, we firstly aimed to resolve different issues concerning the ontogenesis of infants’ ability to process facial expressions. Our results allowed to specify the development of visual exploratory strategies of facial emotions along the first year of life, and to demonstrate that a progressive distinction of expressions according to their emotional meaning is present. Using the EEG, we were also able to specify the nature and the time course of facial expressions distinction in 3-month-old infants.The second objective of our studies was to expand the knowledge concerning the multisensory processing of facial expressions. More specifically we wanted to investigate the influence of olfacto-visual interactions on this processing. Our event-related potentials experiments allowed to specify the time course of the cerebral integration of olfaction in the visual processing of emotional faces in adults, and to demonstrate that similar interactions are present in infants as young as 3 month-old. We also demonstrated that at 7 months of age odors trigger the search for specific facial expressions. Our results suggest that olfaction might contribute to the development of infants’ ability to process facially displayed emotions.