Very curly and frizzy hair protected the first humans from the heat, and, by domino effect, allowed the brain to develop.
- If all hair reduces solar radiation on the scalp, it is curly hair that protects the most from the sun and heat.
- Loops are said to have played an important role in brain development, protecting the skull of early humans from heat and UV rays.
- The scientists used a thermal mannequin for their experiment.
The maintenance of your curly or frizzy hair annoys you? Do you sometimes dream of having long, silky hair like the one you often wear on the red carpet? However, your curls have a major advantage over straight hair… Above all in the summer period. They would help fight the heat. Here is the discovery of a research published in Proceedings of the National Academy of Sciences and conducted by several international universities.
Curly hair provides better sun protection
To determine the role of human hair texture in regulating body temperature, the scientists used a thermal mannequin. This human-shaped object uses electrical energy to simulate body heat. The researchers placed it under lamps imitating solar radiation as well as in a wind tunnel simulating the wind.
The first time the model was presented to the “bald” elements”. For the following measurements, he wore wigs: one smooth, another moderately curly and finally one with very tight curls.
The scientists then calculated the total heat loss recorded between the lamp and the mannequin based on its hair and wind function. Conclusion : while all hair reduced solar radiation on the scalp, very curly hair offered the best protection against heat while minimizing the need to sweat to “stay cool”.
Curly hair would have favored the development of brain
For researchers, the protection offered by curly hair could be one of the keys to the development of the human brain during evolution. As Tina recalls Lasisi who conducted the study as part of his doctoral dissertation at Penn Statethe brain is sensitive to heat and has therefore need to be protected.
For her, the hair probably helped adapt when the first humans who then lived in equatorial Africa began to stand. The curls that appeared made it possible to reduce the harmful effects of solar radiation and heat on the skull. And by keeping humans cool – without the body having to expend additional resources – curly hair would thus have promoted brain development.
“About 2 million years ago we see Homo erectuswho had the same physical constitution as us, but a smaller brain”explained the scientist in a communicated. “And 1 million years ago we were basically the size of the modern brain, more or less. Something released a physical constraint that allowed our brains to grow. We believe that scalp hair provided a passive mechanism to reduce the amount of heat from solar radiation that our sweat glands could not handle.”.