The most basic act of violence, hand-to-hand combat likely helped the evolution of the human hand.

According to The Washington Post, researchers at the University of Utah (UofU) examined the difference between an open handed slap and a closed fisted punch and how they drove the evolution of the human hand. For their study, published in the Journal of Experimental Biology, they used cadaver arms.

"The idea that aggressive behavior played a role in the evolution of the human hand is controversial," study senior author David Carrier, a professor of biology at UofU, said in a press release. "Many skeptics suggest that the human fist is simply a coincidence of natural selection for improved manual dexterity. That may be true, but if it is a coincidence, it is unfortunate.

"As an alternative, we suggest that the hand proportions that allow the formation of a fist may tell us something important about our evolutionary history and who we are as a species," he said. "If our anatomy is adapted for fighting, we need to be aware we always may be haunted by basic emotions and reflexive behaviors that often don't make sense - and are very dangerous - in the modern world."

Carrier came up with the idea that hand-to-hand combat contributed to the evolution of the human hand during an argument about a past study about sexual competition among sperm whales.

"At one point, to illustrate the point he was trying to communicate, he held his fist up in front of my face and said 'I can hit you in the face with this, but that's not why it evolved!' And I thought hey, maybe it did," Carrier told The Post. "I didn't say that at the time, because he was already upset."

Using severed arms as their test subjects, the researchers found a closed fist better protects the hand's bones and also increases the potential for damage, as opposed to an open handed slap.

"The real question was whether or not the buttressed fist provides protection," Carrier told BBC News. "It is a little macabre and strange, but there was no other way to really get this data. You can't implant strain gauges on living subjects."