Lower Testosterone Levels Helped in the Development of Civilization

Drop in testosterone levels accelerated human prosperity, a new study suggests.

It might be a man's world, but femininity laid the foundation for modern civilization, a new study has found.

Modern humans evolved around 200,000 years ago. However, humans started using tools and making art some 50,000 yearsago. The latest study by Duke University researchers explains this gap in human civilization history.

The team said that lower testosterone in humans led to people being nice to each other, which in turn led to the development of civilized societies.

"The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament," said lead author Robert Cieri, a biology graduate student at the University of Utah who began this work as a senior at the Duke University.

The shift in temperament can be gauged from the changes in facial structure. Reduction in male hormones led to softer facial features - rounder heads, less prominent brows.

For the study, researchers analyzed 1,400 ancient and modern skulls. The team found a link between reduction in testosterone levels and growth of civilization. The researchers aren't sure whether humans had less testosterone circulating in the body or had fewer receptors for the hormone.

The research on animals such as the Siberian foxes has already shown that low levels of testosterone leads to juvenile faces and less aggressive behavior. Studies on aggressive chimpanzees and mellow, free-loving bonobos have also shown how differences in male hormone levels affect behavior.

"If we're seeing a process that leads to these changes in other animals, it might help explain who we are and how we got to be this way," said Brian Hare in a news release.

The study "Craniofacial Feminization, Social Tolerance and the Origins of Behavioral Modernity," is published in the journal Current Anthropology.