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Biology of Culture

Jean-Jacques Hublin
p. 16
Cet article est une traduction de :
Biologie de la culture

Notes de la rédaction

Excerpts from the Inaugural Lecture 8 October 2014
Source: La lettre, no. 39, March 2015

Texte intégral

The D4500 Dmanisi skull (Georgia) is one of the oldest pieces of evidence of the colonization of Eurasia by humans 1.8 million years ago.

1Africa long remained central to the evolution and demographics of Hominins. Humans colonized Eurasia only over the last two million years, and finally a species, also originally from Africa, replaced all others and occupied all land areas. It spectacularly modified its environment and extended its hold over the genome of other living forms.

2Human evolution is all the more remarkable in that it results from a bio-cultural process. Like other mammals before them, our most distant ancestors first adapted to new conditions through biological changes affecting their size, their anatomy, their diet, their locomotion, and their mode of reproduction. However, humans’ development of technical behaviours and ever more complex modes of social organization opened a new chapter in the history of life. In the ecological sense of the term, it is a “niche construction”, that is, a species’ modification of its environment to create conditions favourable to its survival and development. Throughout human evolution, vital biological functions have been externalized. That externalization from the biological to the technical and ultimately to the social has enabled humans to adapt to all environments, flexibly but above all reversibly.

3Our brain, which grew strikingly within the genus Homo, played a crucial role in this process. To feed this energy-intensive organ, Homininae profoundly modified their biology, and particularly reoriented their diet towards the consumption of meat and fat. This evolution went hand in hand with an externalization in the technical sphere, following the appearance of stone tools over 2.5 million years BCE. The reduction of the human masticatory system thus began and with it the metabolic cost of its growth. The calories saved in digestion were also reinvested in the development of increasingly large brains.

4A second externalization took place towards the social sphere. The energetic and anatomical challenges raised by the development of a large brain were resolved by the limitation of its size at birth and the prolongation of its growth time. This very late maturation plays a decisive role in the development of our cognitive complexity. At the same time, the development of early weaning has allowed for adults other than the mother to contribute an increasingly large percentage to young humans’ diets. This “bio-cultural reproduction”, which is founded on complex social and emotional ties, has profoundly influenced the emergence of specifically human psychological traits.

5At what point in the past did these adaptations appear? Regarding growth rhythms, it was possible to address this question seriously only with the emergence of studies on dental microstructures. The speed of development was much faster in the Australopithecine than in contemporary humans, and was similar to that of African apes. In Homo erectus, the adult brain size was reached faster than in modern humans and the long learning period that characterizes our species was still far from being in place. Finally, in Neanderthals, though much closer to us, cerebral differences from modern humans still arose from the first year of life and sexual maturity probably continued to be reached earlier than in recent populations. It was therefore only during recent phases of human evolution that a modern mode of development was reached. While it has allowed our cognitive complexity to fully form, it was only made possible by the sophisticated technical and social environment that humans were able to create.

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Légende The D4500 Dmanisi skull (Georgia) is one of the oldest pieces of evidence of the colonization of Eurasia by humans 1.8 million years ago.
URL http://lettre-cdf.revues.org/docannexe/image/2153/img-1.png
Fichier image/png, 1,4M
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Jean-Jacques Hublin, « Biology of Culture », La lettre du Collège de France [En ligne], 9 | 2015, mis en ligne le 25 septembre 2015, consulté le 19 octobre 2017. URL : http://lettre-cdf.revues.org/2153

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Auteur

Jean-Jacques Hublin

Collège de France Pluri-Annual Visiting Professor, Professor and Director of the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology, Leipzig.Homo sapiens is not the product of a linear evolution. It emerged from a thicket of species, the branches of which have overlapped over time and sometimes over space.

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© Collège de France

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