A scientific study reveals how hair is involved in the evolution of the human body. Thus, curly or curly hair would be well to protect the brain from high heat.
Why do people near the equator have more curly hair and those near the North Pole more straight hair? A study published on June 6, 2023 in a magazine of the American Academy of Sciences looked into this question.
This work focused on the time when Homo Sapiens gradually overwhelmed the Neanderthals and Denisovans, over 40,000 years ago. This is when the brain size of our species would have started to increase. “The brain is a large, very heat-sensitive organ that also generates a lot of heat,” Tina Lasisi, one of the project scientists, told National Geographic.
In their investigation, the authors return to the appearance of hair. Our scalp is thus due to our bipedal posture: in this position, the Sun directly hits the head, so human beings have developed their hairs to protect themselves against it. This is also due to the climatic conditions in Africa during this period when Man appeared.
This study developed a so-called "thermal" mannequin with different wigs with real human hair. The model was heated to 35 degrees Celsius in a wind tunnel. Using the wind, the scientists "calculated heat loss at different wind speeds, after wetting the wigs to simulate perspiration" and observed "how different hair textures affect heat gain and loss on leather hairy."
The conclusion of this study "shows that tightly curly hair provides the most effective protection for the scalp against solar radiation, while minimizing the need to sweat to compensate for heat gain." This second parameter is explained by the fact that when wet, curly hair does not stick to the skull.