Right-handedness predominance in 162 baboons (Papio anubis) for gestural communication: Consistency across time and groups.
Résumé
Whether nonhuman primates exhibit population level right manual bias remains a controversial topic. In captive baboons, population-level right-handedness has been reported for both coordinated bimanual
actions and communicative gestures. However, some authors remain skeptical of these findings on both methodological and theoretical grounds. Here, we demonstrated the robustness and the consistency
across time of the pattern of right-handedness for a species-specific communicative gesture in olive baboons (Papio anubis). First, we showed significant correlations in the 26 retested baboons for the
measures of hand preferences between the first and the second session conducted 4 years later (2005–2009) by an observer blind to the previous handedness data. Second, the replication of the study
in 96 novel individuals revealed a similar degree of population-level right-handedness than the one expressed in the first group of 66 subjects investigated in 2005. The implications of the findings are
discussed within a theoretical framework about the origin of hemispheric specialization for language.