Impact of proportion on configural perception of odor mixtures in a newborn mammal
Résumé
Configural perception of odor mixtures appears functional early in life. Recent results underline that after the learning of a binary mixture. (AB) that blends in humans, newborn rabbits respond both to the mixture and to its components. However, after the learning of. a single component they do not generalize to the mixture. This suggests that they perceive more in the mixture than the odor of each. constituent (Coureaud et al., Physiol. Behav. 2008). Here, we pursued the assessment of their configural perception of AB, with the. aim to determine whether specific component proportions of A and B elicit the perceptual emergence of an additional odor in AB. Starting. from the initial composition of the AB mixture, we tested whether pups perceived mixtures with weakly different proportions. of A and B (A-B, A+B) either elementally of configurally. In Exp. 1, 17 pups (age: 2d, 4 litters) were conditioned to A, and tested for. their oral response to AB, A-B, and A+B. In Exp. 2, 2x20 pups (2d, 8 litters) were enforced to learn A- or A+, and respectively. tested with A-, A-B, AB, and A+, A+B, AB. In Exp. 3, 18 and 20 pups (2d, 8 litters) were conditioned to A+B and tested for their. response to A+, B or to A+B and AB. As expected, pups conditioned to A did not respond to AB, but interestingly they responded. to A-B and A+B (>45%; Exp. 1). Additionally, after learning of Aor A+, newborns strongly responded to A-B or A+B (> 70%) but. their response remained poor to AB (<20%). Finally, following the learning of A+B, pups well responded to A+ and B (> 90%) but. significantly less to AB (50%). These results highlight the rabbit newborn ability to discriminate between odor mixtures presenting. slightly different proportions of odorants, and confirm the configural perception of certain odor mixtures by the young animal.