Image: stockxpert
Human hands may have evolved their unique shape in order to better punch the living daylights out of competitors, a new study suggests.
The new findings, published today (Dec. 19) in the Journal of Experimental Biology, show that the clenched fist produces no more force than an open-palm slap, but protects the fingers better. Human's unique hand shape is one of only a few possible configurations that allow an organism to have both manual dexterity and the ability to brutally club opponents, the study reveals.
"Once hands are no longer used in locomotion there could have been many different ways to manipulate and many different ways to punch," said Milford Wolpoff, a paleo-anthropologist at the University of Michigan, who was not involved in the study. "A hand that does both is really limited in its morphology."
The hand shape essentially turns "this relatively delicate musculoskeletal system into an effective club," said study co-author David Carrier, an evolutionary biologist at the University of Utah. [10 Things That Make Humans Special]
Swinging ancestors
This isn't the first time Carrier has argued that humans evolved to fight. Last year he published research suggesting that humans became bipedal to better land crushing blows.
"If you stop and look at what we know about the other species, we're a relatively violent group of mammals," Carrier told LiveScience.
Humanity's ancient ancestors swung from the trees, which meant they needed long fingers for grasping branches. But once Australopithecus afarensis like the famous "Lucy" began walking on two legs between 3.8 million and 2.9 million years ago, their hands were free to evolve improved dexterity. That fueled rapid changes in the human hand, Carrier said.
Yet while chimpanzees also live a terrestrial lifestyle and use their hands for many tasks, they have longer fingers and a scrawny thumb, leading Carrier and his colleagues to wonder whether male aggression played a role in the hand's evolution.
Hurting hands
To find out, the researchers measured the force produced as 12 experienced male boxers and martial artists whacked a punching bag as hard as they could, either with an open palm or a clenched fist.
Surprisingly, both methods produced the same level of maximum force. But the clenched fist delivered that same force to a smaller surface area, meaning it could inflict more tissue damage and be likelier to break bones.
That suggested people use a clenched fist for punching in order to maximize bodily damage to their opponents, not to maximize the force they can produce.
Next, the researchers measured the force generated as participants pushed their hands against a surface in different configurations — one in which the fist was clenched and two others with the thumb sticking out.
The clenched fist could support much more of each participant's body weight without causing the index and third finger to overextend.
The clenched fist, it turns out, "locks the index finger and the middle finger into place, and that's what makes the fist so stiff," Carrier said. The configuration prevents people from injuring their hands while dealing deadly blows, he said.
The team also found that other possible hand shapes, more similar to those found in humans' close relatives, could be equally dexterous but not as deadly.
See what we're tweeting about
10 Comments
Add Comment“the clenched fist… protects the fingers” … therefore the hand evolved for fighting.
Reply | Report Abuse | Link to thisSimply flawless logic.
In all honesty, the “speculative argument from evolution” needs to be retired or detained. Lock it up and throw away the key.
It is completely and utterly ridiculous. It lacks a verifiable path of logical inference (see above), and moreover doesn’t even rely upon any reasonable empirical basis.
What is the scientific rationale for selecting a subset of current human characteristics (from a virtually infinite number of human traits) and then trying to conduct some bizarre, make-shift process of reverse inference to assign these traits to some arbitrary and sexy hypothesis, particularly when this hypothesis cannot be tested or verified in any meaningful way? The very fact that the only hypotheses which get reported on are those which are relevant to a modern world makes this entire process circular: the traits which we see regularly are asserted to be "human nature" and therefore can be inferred to have evolved--insert an "evolutionary mechanism"--and the validity of this mechanism can be confirmed based upon its apparent simplicity and congruity with everyday intuition. In other words, a confirmation bias generator.
We wonder why it is that most people are ignorant about evolution: maybe it’s because the most popular discussions of “evolutionary topics” are little better than a rumour mill or gossip column…
Much easier to grab a club and wack your opponent on the head. The human hand is so complex in its ability to manipulate and control items. Why would it evolve to hit someone in the face. Why not evolve to paint a picture of an elk on the wall of your house, or make a necklace of beads, or apply a dressing to the wounded leg of a friend.
Reply | Report Abuse | Link to thisThe author states that "we're a relatively violent group of mammals" Why assume that that violence is biological in nature as opposed to cultural??? Not all humans are violent, and not all cultures are violent.
The reality is that the hand developed to most effectively pick our noses as we come up with lame ideas.
I think a better case can be made for the hand evolving to grip and throw objects with force and accuracy, along with co-evolution of the lower body that provides a stable platform and thrust.
Reply | Report Abuse | Link to thisI agree with the prior commentators - I'll go further and challenge the researchers to a fist fight - but I get a baseball bat!
Reply | Report Abuse | Link to thisSearching out the freely available (thanks) research report upon which this nonsense is based, I find "Protective buttressing of the human fist and the evolution of hominin hands",
http://jeb.biologists.org/content/216/2/236.full.pdf
This is primarily a physiological assessment of the hand features that make it a superior weapon. The strongest case for any evolutionary preference for the development of the 'buttressed' fist is the sexual dimorphism in the length proportions between the second and fourth fingers allow men, especially for those with higher testosterone levels, to make a stronger fist. While this is only circumstantial evidence, it is at least somewhat compelling - the fist as large antlers supporting successful rutting behavior... However, these issues are never clearly stated in the above article.
Obviously the hand didn't evolve for writing as the author of this article shows.The real reason the human hand became the way it is,foreplay.The smarter the female became the more she rejected suitors that didn't caress her to a certain point.Wham bam thank you mam was no longer tolerated.An unwilling female will look for some other genes to pass on.Makes sense a man caring in sex will be more gentle with children as well,and they will have a better chance to survive.Of course this gentler male would need tools to give him a edge,no pun intended.A fist is no match for for a sharp edged stone tool.It was at this point that brute force lost out to the smarter tool making opponent,and the arms race was on so to speak.There was course a rock throwing club carrying era,but tools clearly won out in the end,and thus the need for a bigger and better brains.
Reply | Report Abuse | Link to thisInteresting idea and clever comments! otherwise if we go along with the author hypothesis we should add a few more findings :
Reply | Report Abuse | Link to this1) a strong grip for tools is perfectly compatible with a strong grip for weapons and these are probably more compelling for evolution than fist power against your pals! Let's think about a primitive man who could win a fist fight against everybody but would be hopeless to manipulate weapons for hunting and defense ... he would be quite hopeless.
2) "either with an open palm or a clenched fist. Surprisingly, both methods produced the same level of maximum force. But the clenched fist delivered that same force to a smaller surface area, meaning it could inflict more tissue damage and be likelier to break bones." ... Nice :-) , but a few things are missing :
a) the clenched fist gives up to 10 more centimeters of reach compared to an open palm.
b) the open palm on a complicated target it's likely to torn a few finger and in addition to its larger surface to reach the target with some sort of pillow effect.
But frankly these advantages are probably minimal when many sort of wood and stone weapons are available.
... By the way if fighting your brothers was SO important ( may be a bias of modern men in a shrinking world :-) ) we would probably have stronger jaws. For example chimps have quite a strong biting power which imply that a chimp human fight without weapons is hopeless for the man, except may be if he is at least 3 times heavier, trained for it and lucky, and as far as I know, this had never happened.
Just so stories.
Reply | Report Abuse | Link to thisThis article misses a very important point.
Reply | Report Abuse | Link to thisHITTING SOMEONE IN THE HEAD WITH YOUR FIST WILL BRAKE THE BONES IN YOUR HAND !!!
I agree with most of the above comments - especially No 8.
Reply | Report Abuse | Link to thisOne of the basic rules of self defence is to use *anything* immediately available as a weapon - in order to protect your hands.
Pens, pencils, combs,rolled up magazines, ashtrays, cups glasses, ornaments, tools, stones, sticks, feet/shoes etc...
Finally in an indoor situation, instead of striking a blow with a fist - it is much better to lunge forward with an open hand so you can grasp the attackers face and shove the back of the attackers head into a wall or a piece of furniture as hard and fast as possible - this minimises risk to your fingers which if damaged will make you very vulnerable in the case of multiple assailants..
Some of these so called experts have been watching far too much TV!
Thanks zstansfi, my thoughts exactly!
Reply | Report Abuse | Link to thisI'm so tired of hearing these kinds of speculations which cannot be proved or disproved - especially because most of them are used to justify some existing injustice (usually the inequality between men and women) as only 'natural'.
Having said that, it's worth speculating about our evolution - but only worth taking those speculations seriously if we can check them against evidence.
It's also worth remembering that just because we're made a certain way that doesn't mean we have to behave that way. We have conscious minds and we can choose (whatever the determinists and other fundamentalist types say).
We don't need to allow violence to dominate our societies, for example. We can choose to cultivate more peaceful and compassionate behaviour.
See for example the Charter for Compassion
http://charterforcompassion.org/.