The human brain has shrunk in size in the last 30,000 years . Specifically, the latest measurements reveal that the average volume of the Homo sapiens brain in this period has decreased by 10%, that is, from 1,500 to 1,359 cubic centimeters, the equivalent of a tennis ball . The phenomenon intrigues anthropologists, who mostly value it as an effect of the evolution towards more complex societies.
According to the latest measurements, the reduction in brain size could be explained to the extent that the more muscle, the more gray matter is needed to control a body. Neanderthal man, who disappeared 30,000 years ago, was bigger and had a bigger brain. The Cromagnon man, who made the cave paintings in the Lascaux grotto (France) 17,000 years ago, was thehomo sapiensendowed with the largest brain, but he was also stronger than his current descendants. “These traits were necessary to survive in a hostile environment,” explains David Geary, a professor of psychology at the University of Missouri and the author of several papers on the development of the human brain throughout evolution.
Based on this finding, this researcher has studied the evolution of the size of the skull between 1.9 million years ago and 10,000 years ago, as our ancestors lived in a more complex social environment. Geary starts from the principle thatthe higher the human concentration, the more exchanges there are between the groups, the greater the division of labor and the richer and more varied are the interactions between individuals. It has also found thatbrain size decreases as population density increases. “With the emergence of more complex societies, the human brain has become dwarfed becauseindividuals no longer need to be so smart to survive; the others help them“, he explained to the AFP agency.
This reduction of the brain does not mean that modern men have less intellectual capacities than their ancestors, but that they have developed more sophisticated forms of intelligence, clarifies Brian Hare, associate professor of anthropology at Duke University in North Carolina. According to him, there is a similar parallel between domesticated and wild animals. Thus, the wolfdog has a smaller brain than that of the wolf, but it is more intelligent and sophisticated, because it understands the communication gestures of men. Which shows that“There is no close correlation between brain size and IQ”, which is defined above all by the ability to induce and create, adds Hare.
