Ancient "bar fights" over women may have contributed to the evolution of the human face.
New research suggests that human faces, especially in the australopith ancestors, developed to minimize injuries sustained from punches to the face, a University of Utah Health Sciences news release reported.
"The australopiths were characterized by a suite of traits that may have improved fighting ability, including hand proportions that allow formation of a fist; effectively turning the delicate musculoskeletal system of the hand into a club effective for striking," University of Utah biologist David Carrier said in the news release. "If indeed the evolution of our hand proportions were associated with selection for fighting behavior you might expect the primary target, the face, to have undergone evolution to better protect it from injury when punched."
The researchers looked at a number of factors in order to make their findings.
"When modern humans fight hand-to-hand the face is usually the primary target. What we found was that the bones that suffer the highest rates of fracture in fights are the same parts of the skull that exhibited the greatest increase in robusticity during the evolution of basal hominins. These bones are also the parts of the skull that show the greatest difference between males and females in both australopiths and humans. In other words, male and female faces are different because the parts of the skull that break in fights are bigger in males," Carrier said.
These facial features started to appear around the same time that hands had reached the right dimensions to form a fist.
The research suggests violence had more influence on evolution than has previously been accepted by science.
"The debate over whether or not there is a dark side to human nature goes back to the French philosopher Rousseau who argued that before civilization humans were noble savages; that civilization actually corrupted humans and made us more violent. This idea remains strong in the social sciences and in recent decades has been supported by a handful of outspoken evolutionary biologists and anthropologists. Many other evolutionary biologists, however, find evidence that our distant past was not peaceful," Carrier said.
