Elle est liée notamment à la controverse « du feu ou de la viande » exposée dans cet article et les suivants, et plus succinctement dans ce thread twitter.
2. Déterminants de l’évolution du cerveau
Données sur l’évolution du cerveau humain
Pour la partie quantitative, au moins deux aspects sont à considérer : la taille absolue du cerveau, et sa taille relative, avec la notion de coefficient d’encéphalisation.
Les méthodes employées sont diverses : mesure directe du volume intracrânien à partir des fossiles retrouvés, inférence de la forme du cerveau à partir des traces laisées à l’intérieur des boites crâniennes, ou mesure de la capacité d’irrigation sanguine de la boite crânienne…
Andrew Du et al.
The Royal Society Publishing, 2018
Our results show that fossil hominin ECV data at the clade level are most consistent with a gradual pattern of ECV increase through time. Understanding how this pattern emerged from processes that operate at lower taxonomic levels is more com-plicated. Our analyses are consistent with microevolutionary mechanisms as the dominant driver of clade-level change (64 or 88% of change using a more or less speciose taxonomy, respectively), alternating with secondary macroevolutionarymechanisms. This implies changing selective pressures and shifts in the relative importance of different evolutionary processes through time.
Journal of creation theology and science, 2016
Jean-Jacques Hublin et al.
The Royal Society Publishing, 2015
There is a consensus that Australopithecus endocasts show signs of brain reorganization and depart from the sulcal patterns found in apes, despite their ape-like endocranial volumes. It is therefore possible that brain reorganization in australopiths and its cognitive consequences underlie the subsequent brain expansion in the genus Homo. Furthermore, if supported by further investigations, the protracted pattern of brain development in A. afarensis would confirm that one cannot simply contrast a primitive ‘ape-pattern’ to a ‘human-pattern’.
The relationship between encephalization quotient (EQ) and body weightis found to be consistently negative within all hominid species
Ruff et al.
On the basis of an analysis of 163 individuals, body mass in Pleistocene Homo averaged significantly (about 10%) larger than a representative sample of living humans. Relative to body mass, brain mass in late archaic H. sapiens (Neanderthals) was slightly smaller than in early ‘anatomically modern’ humans, but the major increase in encephalization within Homo occurred earlier during the Middle Pleistocene (600–150 thousand years before present (kyr BP)), preceded by a long period of stasis extending through the Early Pleistocene (1,800 kyr BP).
Déterminants de l’évolution du cerveau
Hanna Tuomisto et al.
Ecology and evolution, 2018
The hypotheses proposing that encephalization was triggered by improved nutrition also received intermediate popularity scores, whether achieved by cooking or by increased consumption of fish or meat (all three with credibility scores in the range 2.61–2.77).
The evolutionary roles of nutrition selection and dietary quality in the human brain size and encephalization
Roberto Carlos Burini, William R. Leonard
In addition to the energetic benefits associated with greater meat consumption, it appears that such a dietary shift would have also provided increased levels of key fatty acids necessary for supporting the rapid hominid brain evolution .
Half of human brain composition is fat, and 20% of its dry weight is long-chain polyunsaturated fatty acids (LCPUFAs). Consequently, improvements in consumption of dietary fat were a necessary condition for promoting encephalization [61, 62].
Mammalian brain growth is dependent upon sufficient amounts of two LCPUFAs: docosahexaenoic acid (DHA) and arachidonic acid (AA), and it appears that mammals have a limited capacity to synthesize these fatty acids from dietary precursors. Hence, species with higher levels of encephalization would have greater requirements for DHA and AA . Consequently, dietary sources of DHA and AA were likely limiting nutrients that constrained the evolution of larger brain size in many mammalian lineages .
Adrian C Williams, Lisa J Hill
International Journal of Tryptophan Research, 2017
Richard Wrangham, 2017
DeCasien et al.
Nature ecology & evolution, 2017
Here, we use a much larger sample of primates, more recent phylogenies, and updated statistical techniques, to show that brain size is predicted by diet, rather than multiple measures of sociality, after controlling for body size and phylogeny. Specifically, frugivores exhibit larger brains than folivores. Our results call into question the current emphasis on social rather than ecological explanations for the evolution of large brains in primates and evoke a range of ecological and developmental hypotheses centred on frugivory, including spatial information storage, extractive foraging and overcoming metabolic constraints.
Mais attention, ce résultat ne peut pas être étendu aux humains, dont le cerveau est trop atypique :
Alianda M. Cornelio et al.
Frontiers in neurosciences, 2016.
Daniel E. Naya et al.
Comparative biochemistry and physiology, 2016
Kuzawa et al.
Proceedings of the national academy of science, 2014
We find that the brain’s metabolic requirements peak in childhood, when it uses glucose at a rate equivalent to 66% of the body’s resting metabolism and 43% of the body’s daily energy requirement, and that brain glucose demand relates inversely to body growth from infancy to puberty. Our findings support the hypothesis that the unusually high costs of human brain development require a compensatory slowingof childhood body growth.
Cunnane et al.
American journal of human biology, 2007
Henry T. Bunn, 2006
Katharine Milton, 2003
The expensive-tissue hypothesis : the brain and the digestive system in human and primate evolution. Leslie Aiello, Peter Wheeler, 1995.
Graphique évolution du cerveau et acquisitions culturelles humaines
Bradshaw foundation, 2012, pour le visuel original.