When talking about addictionsHomo sapiensWe think about tobacco, alcohol, sugar and other substances, gambling or possibly sex, but we forget what dominates us and turns out to be the source of many of today’s ills: our appetite for energy. As the paleoanthropologist Jean-Jacques Hublin writes, in his book The tyranny of the brain (Robert Laffont, 320 pages, 21 euros), humans constitute “the only species capable of extracting energy from its environment in an almost unlimited way, and not only in the form of food”.
And this race for joules or calories has its roots in the energy needs of the organ that most differentiates us from the rest of the great apes, our brain.
Our big brain, should we write instead? Approximately three times larger than that of our closest cousins, chimpanzees. And if it only represents 2% of the mass of an adult, it consumes 20% of its energy. This is still quite little compared to the 40% to 50% that a newborn’s brain consumes and the almost 70% that goes into the brain development of a 5-year-old! Based on these surprising results, Jean-Jacques Hublin makes the original decision to narrate the evolution of the human race through the prism of the brain and the control it has exercised, both in terms of physiology and behavior.
Carnivore, hunter and cook.
Accommodating such a glutton in the body implies, in fact, adaptations, redistributions, subcontracting, a bit like in a factory that must modernize its production processes. the genre Homo It will thus look for a better source of energy than plants and will become more carnivorous than any other primate. Our ancestors, emphasizes Jean-Jacques Hublin, “Thanks to their stone tools, they could break [les] bone [de leurs proies] and extract the marrow, a fatty tissue very rich in calories.”. Carnivore, therefore, but also a hunter and cook, a cuisine that allows savings in the chewing and digestive system.
It is also more energy efficient to move on two legs, but the vertical posture, by narrowing the pelvis, poses a serious obstetric problem for the pregnant woman, even if the fetus’s head swells: there is a risk of not leaving the mother’s body. matrix. Hence a compromise: give birth to immature babies and delay the growth of their brains after birth, during a very long childhood. Which, in turn, implies limitations for the mother and, more broadly, for everyone around her, who must organize themselves at a socioeconomic and technological level to provide their calories to these young unproductive humans.
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