Culture rose in ancient humans as testosterone fell, study says

Courtesy Robert Cieri | University of Utah Robert Cieri used facial measurements from more than 1,400 ancient and modern human skulls for a study that suggests reduced testosterone levels in humans accompanied the advent of modern human behavior and culture. Cieri, now a biology graduate student at the University of Utah, led the study when he was a senior at Duke University. He made some of the skull measurements himself; others were taken from previous studies.

Research University of Utah grad student publishes study.

Modern culture among ancient humans began to rise as levels of testosterone associated with macho, aggressive behavior fell, according to a new study conducted by a University of Utah biology graduate student.

Robert Cieri and other researchers studied 1,400 ancient and modern human skulls, finding that their characteristics became more feminine as time progressed, indicating lowering testosterone levels. This reduction in testosterone coincided with leaps forward in human technology and culture about 50,000 years ago, Cieri said. Modern humans, or Homo sapiens, first appeared in the fossil record about 200,000 years ago.

"A reduction in testosterone makes people more socially tolerant. It makes them more cooperative and, as a result, people can more easily learn from and teach one another," Cieri said. "It becomes much easier to pass down innovations from one person to another and build a complex culture."

Brow ridges receded and the length of the face between the eyes and the top of the jaw shortened in the skulls from after 50,000 years ago versus before, Cieri found in the study, which was published Friday in the journal Current Anthropology.

Humans didnt became more girly in order to evolve culturally and intellectually. Rather, features considered hyper-masculine began to go, he said.

"Its not necessarily that people are acting more like females, its just kind of this overly aggressive, intolerant phenotype was maybe selected against," Cieri said.

He said its possible testosterone began to dive as humans grew more populous and began living in more tightly packed conditions.

"It could have happened because as population density started increasing people were living closer together and had to get along," Cieri said.

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Culture rose in ancient humans as testosterone fell, study says

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