"The Surprising Role of Curly Hair in Early Human Brain Development"

Curly hair in early humans served as protection against the sun's radiative heat, keeping them cool and contributing to the growth of the human brain. A study using thermal mannequins and human hair wigs found that tightly curled hair offered the best protection against solar radiation, reducing the need to sweat to stay cool. As early humans adapted to walking upright in equatorial Africa, their exposed heads became increasingly vulnerable to heat. Scalp hair likely evolved as a natural mechanism to minimize heat absorption, allowing the brain to grow without the risk of overheating.