Researchers have studied human skulls to determine the origins of human civilization. They associated the first inventions of man and a decline in male hormones.
Dominance, power, aggressiveness… These behaviors are often associated with an excess of testosterone in animals, in particular in males. But what about humans? A new study, published in the journal Current Anthropology, suggests that the drop in testosterone levels in men, which occurred 50,000 years ago, may be linked to technical and artistic progress at the time.
Less testosterone, more cooperation
Professors at the University of Utah (United States) studied 1,400 ancient and modern skulls, including 13 over 80,000 years old and 41 between 10,000 and 36,000 years old. Thanks to their shape, they were able to determine how much of the male hormones had regressed. And the observed drop in testosterone almost always corresponds to the prosperous periods which saw the birth of the first inventions of men. “Modern human behavior and technical innovation, which allowed rapid cultural exchanges and the birth of art, probably appeared at the same time as we developed a more cooperative behavior,” explains Robert Cieri, one of the authors of the study. On the other hand, it remains impossible to determine whether it is the drop in hormones that caused this, or if the phenomenon is the opposite.
Conflicting studies in humans
Testosterone is a hormone that plays a significant role in the organization of various brain structures, but also in the sexual behavior of individuals. Numerous studies have shown that these molecules can cause aggressive, egocentric and dominant behaviors in animals. Conversely, a reduction in these hormones could reduce these excesses. A good deal of research has been done to determine the influence of these hormones on human behavior, but the results are rather mixed. Studies confirm that an excess of testosterone, especially in humans, is a source of stress and aggression. Others dispute this data. This is the case of a publication published in Nature in 2009, whose participants who had been injected with a dose of testosterones had shown more honesty in a gambling game than those who received a “placebo” dose of these same hormones.
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