Prehistoric Society bloomed with Gentler Personalities and Features

[Blind Hemingway]

Scientists have shown that human skulls changed in ways that indicate a lowering of testosterone levels at around the same time that culture was blossoming. Heavy brows were out, rounder heads were in. Technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament by dialing back aggression with lower testosterone levels.