Studying lateralized behaviors in living humans: an application in the context of a project on brain evolution in hominins.
Ameline Bardo: UMR 7194, CNRS, PaleoFED team, Département Homme et Environnement, Muséum national d’Histoire naturelle, Paris, France; Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom.
Evolutionarily adaptive characteristics, including increase of specialization of brain’s hemispheres and specific hand morphology such as a longer thumb-finger ratio are generally associated with enhancements in manual dexterity and fine motor movements. Cognitive and functional understanding in the fossil record, however, can only be inferred through inferential and comparative analysis of morphology and function with extant hominids capabilities. However, can we discuss the relationship between past behaviors and brain morphology? The PaleoBRAIN project aims to study for the first time the correlation between the shapes of the brain and the endocast within a sample of modern humans using MRI acquisitions, including some with a specific sequence more sensitive to the of bone tissues signal, with the final aim to bring the brain of Homo erectus and Neandertals back to life.
Multidisciplinarity and interdisciplinarity will be strong components of PaleoBRAIN and an essential condition to achieve the scientific objectives. In this context, I will study the behavioral asymmetries on the same sample of volunteers, by studying key behaviors (e.g., manipulation, vision, communication, dichotic listening), as well as the relationship between form and function of their hands. Indeed, in the modern day, hand function is affected in part by demographics and lifestyle factors but a comprehensive understanding into the relationship between dexterity and these factors, as well as with manual asymmetries, is not overly understood. This study will allow discussing the possible relationships between brain asymmetries and behavioral asymmetries in living humans, and will improve our understanding of the link between form and function for both hands in modern humans. I will present here the methods and the principal aims of this study, which is part of PaleoBRAIN. In the long term, this project will provide a crucial referential context for a better understanding of the anatomy and the behavior of fossils.