According to a new British study, the increase in the brain of Homo sapiens is due to environmental difficulties encountered over time.
It is a long established fact: the brain of Homo sapiens has more than tripled since the Australopithecus period 4 million years ago. But why ? Did the brains of our ancestors develop according to their needs, in order to control their environment and survive? Or is it on the contrary, because their brain has evolved that they have been able to set up more developed social and cultural relations? For decades, researchers have been advancing theories, each more different than the next.
A new British study published on May 23 in the scientific journal Nature could finally make it possible to decide. According to her, the increase in the size of the human brain is mainly due to environmental difficulties encountered over time. To come to this conclusion, Mauricio Gonzalez-Forero and Andy Gardner, from the University of St Andrews (United Kingdom) simulated the evolution of the brain in different situations: ecological, social or conflicts between individuals. Result: “We have observed that the human brain increases when it is confronted with problems due to its natural environment”, explains Mauricio Gonzalez-Forero.
Having to constantly find solutions to feed himself in the savannah “where the environment changes seasonally”, to store water, conserve and transform food while achieving fire control, man has had no problem. no other choice than to adapt to its environment and find solutions.
A study which arbitrates the different theses
By evaluating the different factors that caused the growth of the brain according to the energy spent by it to respond to each of the challenges, this study therefore today arbitrates the debate between the defenders of the ecological thesis, those of the thesis social and those of the cultural thesis.
“Evolving modeling in this way can provide accurate predictions of brain size that cannot be easily falsified.” , explains Richard McElreath of the Department of Human Behavior, Ecology and Culture at the Max Planck Institute for Evolutionary Anthropology, in a commentary associated with the study. And to detail: “When the results of the model do not correspond to the observed brain sizes, the biological hypotheses can be studied to see why the model did not work”.
60% due to the environment, 30% due to social interactions
But if the environment would have influenced up to 60% in the evolution of the human brain, it would also be due (30%) to social factors, or to the cooperation necessary for survival. It would indeed seem that this cooperation between individuals was much more beneficial to Homo sapiens than the tensions between homnids since the latter would have influenced only 10%.
Indeed, conflicts between humans belonging to the same group are “not important” in the evolution of the brain, according to the study. Conclusion, which should finally unite everyone: the “results suggest that it is the interaction between the difficult environmental conditions and the culture which determined the size of the human brain”.
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