RESEARCH ARTICLE Can Population-Level Laterality Stem from Social Pressures? Evidence from Cheek Kissing in Humans Amandine Chapelain1*, Pauline Pimbert1, Lydiane Aube1, Océane Perrocheau1, Gilles Debunne3, Alain Bellido2, Catherine Blois-Heulin1 1 UMR 6552 Université de Rennes 1—CNRS, Station biologique, 35380, Paimpont, France, 2 UMR 6553 Université de Rennes 1—CNRS, Station biologique, 35380, Paimpont, France, 3 QDC, département R&D, 31000, Toulouse, France *
[email protected] Abstract Despite extensive research, the origins and functions of behavioural laterality remain largely unclear. One of the most striking unresolved issues is the fact that laterality generally occurs at the population-level. Why would the majority of the individuals of a population exhibit the same laterality, while individual-level laterality would yet provide the advantages in terms of OPEN ACCESS improving behavioural efficiency? Are social pressures the key factor? Can social pressures Citation: Chapelain A, Pimbert P, Aube L, induce alignment of laterality between the individuals of a population? Can the effect of Perrocheau O, Debunne G, Bellido A, et al. (2015) social pressures overpass the effect of other possible determining factors (e.g. genes)? We Can Population-Level Laterality Stem from Social tested this important new hypothesis in humans, for the first time. We asked whether popu- Pressures? Evidence from Cheek Kissing in Humans. lation-level laterality could stem from social pressures. Namely, we assessed social pres- PLoS ONE 10(8): e0124477. doi:10.1371/journal. pone.0124477 sures on laterality in an interactive social behaviour: kissing on the cheek as a greeting. We performed observations in 10 cities of France.