Rachel Feltman, writing for the Washington Post:
According to a study published in Current Anthropology, our transition into modern civilization might have coincided with our species’ drop in testosterone.
The hormone, associated with both biologically male characteristics and aggression, makes skulls grow those heavy brows we associate with our evolutionary ancestors. Lead author Robert Cieri, a graduate student of biology at the University of Utah, said in a news release that a study of 1,400 modern and ancient skulls provided insight into how these changes might have overlapped with cultural shifts.