Developmental changes in elemental and configural perception of odor mixtures in young rabbits

Development can change the way organisms represent their environment and affect their behavior. In vision, complex stimuli are treated as the sum of their elements (elemental perception) in children or as a whole (configural perception) in adults. However, the influence of development in elemental/configural perception has never been tested in olfaction. Here we explored this issue in young rabbits, which are known to perceive during the neonatal period certain binary odor mixtures elementally and others weak configurally. Using conditioning and behavioral testing procedures, we set out six experiments evaluating the putative evolution of their odor perception between birth and weaning. Results highlighted that between postnatal days 2 and 9 the perception of an initially weak configural mixture became robust configural while that of two elemental mixtures did not. Additional switches from elemental to configural perception were observed at postnatal day 24. The use of a chemically more complex senary mixture resulted also in a shift from weak to robust configural perception between postnatal days 2 and 9. Thus, the perception of certain odor mixtures may rapidly evolve toward a more holistic mode in young rabbits, which may help simplifying their representation of the environment once out of the nest.