Dead People's Fists Suggest Fighting May Have Helped Humans Evolve

By Aatif Sulleyman on at

The human hand developed in its own unique way because of our 'dark side', according to research from the University of Utah. Biology professor and lead author David Carrier has suggested that our hands evolved for fighting, as well as using tools, and his theory hasn't gone down too well.

In a fairly gruesome experiment, Carrier and his team attached guitar knobs and lengths of fishing line to the tendons of nine cadaver arms (which were supplied by the university’s body donor programme and a private company (we dread to think)), allowing them to easily manipulate the movements of the corpses' wrists, fingers and thumbs. They then used eight of these, as one was deemed too arthritic, to whack a padded, force-detecting dumbbell.

The most important bit now -- three different types of strike were used and analysed. The researchers forced the dead hands to either punch with a clenched fist, with the thumb folded over the tightly-curled index and middle fingers, hit with an 'unbuttressed' fist, which involves the thumb pointing away from the hand, or slap with an open hand. They found out that we can typically strike with 55 per cent more force with a fully-clenched fist than with an unbuttressed fist, with proper punches generating twice as much force as slaps.

“Many skeptics suggest that the human fist is simply a coincidence of natural selection for improved manual dexterity,” said Carrier. "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. 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. 

"There’s a real fear that evidence suggesting we’re anatomically built for fighting could be used to justify bad behavior. What I would argue is that if our goal is to reduce violence in the future, we need to understand what this dark side of human nature is all about.”

Now who ordered a knuckle sandwich? There's plenty to go round.

Image credit: Duncan Yoyos via Flickr