Skull evolution: Less testosterone made us artistic, civilized

By Casey Frye, CCNN Writer

skull-volution
A researcher carefully measures a skull, to see how our body chemistry has evolved over time.

Beginning around the 14th century, Europe experienced a cultural movement known as the Renaissance. In this time, people focused their energy on advancing literature, politics, mathematics, science, technology, and fine arts, creating breakthroughs that still influence much of today’s society. Well, according to a new study, cultural movements like the Renaissance may not have happened at all if the human body hadn’t undergone major chemical changes!

See, our bodies are constantly maintaining a delicate balance of hormones – chemical messengers that regulate bodily activities and behaviors. There are several dozen hormone types, which contribute to processes such as digestion, stress, sleep, hunger, and blood sugar levels. One hormone known as testosterone influences behaviors such as aggression, risk-taking, trust, and how we develop social relationships. Higher amounts of the chemical messenger is also associated with increased body and facial hair, stronger brow ridges, larger muscles, and bigger bone mass. Based on research from the University of Utah, humans became more artistic and civilized when their levels of testosterone decreased!

In the study, anthropologists – scientists who analyze past and present humans – wanted to understand why there was such a big boom in cultural art about 50,000 years ago. They studied approximately 1,400 skulls of modern and ancient humans. Compared to the ancient humans, the more modern skulls were significantly rounder and more feminine. Interestingly enough, these are characteristics of decreased hormone levels circulating about the body.

What this means for human behavior, is that those decreased chemical levels might have made people more trusting and cooperative, less aggressive, and generally nicer to each other.  These personality traits then allowed individuals to collaborate and share ideas. “If prehistoric people began living closer together and passing down new technologies, they’d have to be tolerant of each other,” said Robert Cieri, the lead researcher of the study. “The key to our success is the ability to cooperate and get along and learn from one another.”

Now, if only we can figure out what caused the levels of testosterone to decrease in the first place…

Images courtesy of University of Utah.