While we all collectively shake our heads and roll our eyes whenever Dana White breaks out the old “fighting is in our DNA” mantra, a new study argues that The Baldfather might not be that far from the truth. Sort of.
David Carrier, a professor of biology and comparative physiologist at the University of Utah, has spent years studying the impacts of fighting on the evolution of the human hand. Back in 2012, he published a report in the Journal of Experimental Biology that attempted to prove his controversial theory that the human hand — which features a shorter palm, shorter fingers and a longer thumb than our primate ancestors — evolved to meet much more than increased dexterity needs.
”If a fist posture does provide a performance advantage for punching, the proportions of our hands also may have evolved in response to selection for fighting ability, in addition to selection for dexterity,” said Carrier.
Carrier’s initial experiment was rather simple. Gathering a group of volunteers between 22-50 — all of whom had previous boxing or martial arts experience — Carrier asked them to hit a punching bag with a variety of strikes ranging from an open palm to a closed fist. Unsurprisingly, the closed fist strikes provided three times more force than an open palm strike on average, while “the buttressing provided by a clenched fist” increased the stiffness of the knuckles fourfold and doubled the ability of the fingers to deliver a punching force.
Carrier noted several other significant evolutionary sightings among primates to back his study — mainly, the difference in body size between the sexes (known as sexual dimorphism), which tends to be greater among primate groups where there is more competition between males. Basically, as the human hand was growing more delicate, it was forced to evolve from one based around open palm striking to the closed fist in order to inflict damage on opponents without damaging itself. The fact that no ape other than humans hits with a clenched fist seemed to support Carrier’s theory.
Likewise, Carrier additionally argued that the male human face may have developed a stronger and more prominent jaw, cheeks and brow to withstand more punches in these often ferocious competitions for mates. The anecdotal nature of the evidence gathered to support Carrier’s theory, however, led to it being challenged by a number of his colleagues across the scientific board.
One such challenger was Professor Frank Fish, a biomechanist at West Chester University in Pennsylvania, who argued that, just as the sperm whale’s bulging head had not developed for ramming other male whales to compete for females, the male fist had not evolved to do the same. “I can hit you in the face with this, but it did not evolve for that!” said Fish, suggesting that the effectiveness of the closed fist in combat was merely the result of the evolution of the human hand, not the impetus behind it.
Cut to last week, when Carrier published additional research in opposition to Fish’s claims. (via The Daily Utah Chronicle):
Carrier, with graduate student Joshua Horns, tested the force of three different hand positions when hitting a weight. They observed how much strain was put on the bones, proving that a full fist is better at protecting the hand when in combat.
Using cadaver arms, Horns removed the skin and attached fishing lines to different muscle groups in the arms. Guitar tuners were adjusted to change the tension of the hand and position it as an unclenched fist, a fully clenched fist and an open-palmed slap. The hands swung into a dumbbell and they measured the impact the force had on the bones.
According to the LA Times, the results were quite impressive, if not entirely conclusive.
“As expected, they found that the clenched fist, buttressed with the fingers tightly curled into the palm and the thumb providing reinforcement across the knuckles, reduced deformation in the metacarpals, thus lowering the risk of breakage.”
The main issue continues to be that, as Fish argues, many parts of the human body *can* be used in combat, but did not evolve specifically for that purpose.
One way to dig deeper, Fish said, would be to study fossils from our predecessors, including species in the genus Australopithecus, and see whether there have been changes through time that developed a better-buttressed fist.
Harvard University’s biological anthropologist, Richard Wrangham, also seems to believe that, in order to truly test Carrier’s theory, the evolution of primal female species should be studied as well. Carrier’s tests have thus far been composed using only male test subjects, and should he find a similarly significant evidence about the evolution of the female hand, it would more or less invalidate his “fighting as an evolutionary catalyst” claims.
It’s an interesting idea that Carrier is hypothesizing, to say the very least, and one that he feels has come under such fire because, if proven, could possibly align with those of us who use the “fighting is in our DNA” discourse to justify violence.
“The way I respond to that is by saying understanding is not justification,” said Carrier, who clearly has never painted JUST BLEED across his chest like the true savages among us.
Check out some more of Carrier’s findings over at EurekaAlert.