Did humans trade weakness for precision?

[bascule]

Is the reason that humans are so much weaker than chimpanzees due, in part, to our enhanced precision of movement?

 

Are our muscles specialized not for strength, but to work in tandem with our highly complex brains to execute precision movements?

 

I've just read that no chimpanzee has ever been trained to thread a needle. Is this simply a deficiency of the chimp brain, or do its muscles also prevent it from executing such precise movements?

[abskebabs]

I have no idea whether the brain or the muscles of the chimpanzee(or both) are responsible for this deficiency. However I think it is higly plausible that humans have traded weakness for precision in their muscles; especially in the hands. Most importantly I think it is the fact we have the 4 fingers and a thumb that have helped us out the most. This would critcal in the first forms of tool making and operating and has continued to remain important to us. For example, dolphins may be blessed with bigger brains than us, but we have been enabled to advance because of the versatillity we are provided with by our hands.

[Rocket Man]

my opinion, we so rarely use our muscles to their full extent that a chimp seems stronger.

theres two things that contribute to strength, muscle mass and tone. use it at max load, it gets bigger, use it a lot at less load, it gets stronger.

 

we have more manual dexterity because of our opposable digit, but we lack strength because we use technology to compensate. we dont spend all our time swinging from tree to tree.

 

if you go to an indoor rock climbing centre, look for the finger board. people climb using only their fingers and upper body strength. more use makes more strength

it's also a matter of practice, most people have never used their full strength, they just havent learned how, spend your time writing, you get good at writing, spend your time tree hopping, you get good at tree hopping.

 

some people cant use their full strength because of a weakness in other areas. top cyclists have huge leg strength but scrawny arms, useless at tug-o-war.

if you spent a month running from predators, you'd soon get a little stronger.

 

we might be specialised for precision but adrenalin strips precision and gives us greater strength, thats why you shake when you get an adrenalin rush.

i think adrenalin helps activate the whole muscle all at once. like turning up the gain on your nerves. we can actually use a very small portion of muscle rather than the whole lot to get better fine control.

[Edtharan]

Due to an injury I have visited with rehabilitation specialists that have taught me a lot about strength. In one session we talked about how, if we don't use muscles, we will feel pain in them when we use them (I think most people have experience muscle stiffness at some point).

 

This pain is not from actual damage or injury, but from the fact that our muscles are not used to that movement or strain (proreception - spelling?).

 

Streching just makes our muscles more use to this movment and so we don't get the pain response. This is also the case with strength.

 

Muscles do bulk up with excersize, but a lot of the strength we feel comes from knowing that we can use it. In times of stress (when the adrenalin is flowing) we are capable of what, to normal experience, seems like a superhuman effort. Actually, what is occureing is that the adrenalin is suppressing this feeling of a limit and allowing the full strength to be acessed.

 

There is a good biological need for this limitation. If we were to operate at the full level all the time, we would stand a greater chance of injuring ourselves. So by having a learned limit, we are better able to operate without injury.

 

The fact that it is a learned response means that it is posable to unlearn it. And this is what a lot of training is all about, not just building the muscles, but reteacing us the limit (and because a lot of athletes do operate with a higher limit, they are more prone to injury - what I was saying about why the limit is needed).

[Sisyphus]

I'm not sure about the strength part (since I've never handled chimps), but it does seem like our excellent fine motor skills require a lot of practice doing intricate things, which in turn requires the intelligence to understand those things. The question of whether our muscles are inherently more suited to precision tasks doesn't seem separable from brain function unless you can show something different about the muscles themselves, and why they favor their respective specialties.

 

BTW, how strong are chimps, pound for pound? Stronger than trained human athletes?

[Sayonara]

The thing with mammalian muscles is that they are like foreign language - on an individual level, it is quite literally a case of "use it or lose it".

 

If you do a physically demanding job, or work out in the gym every day, you will see an increase in muscle mass and probabaly also in working endurance. This is because the muscle fibres grow to accomodate the level of demand that is placed on them (note that no new fibres are added - the number of fibres you are born with is the most you will ever have).

 

Up until the age of about 25-30, when human growth hormone levels begin to decline, it is relatively easy to push your muscles from their current state, into a state that better reflects their maximum potential size and capacity. After this age it is much harder, but still possible.

 

So it is perhaps not entirely accurate to say that we have "lost" our strength, because it is still there as a potentiality. It's more the case that our bodies allow a sort of controlled atrophy to conserve resources, because muscles are expensive to maintain and, by and large, people simply don't use them that much.

 

Wipe out the labouring classes and slap a blanket ban on all forms of exercise, and after a good few generations we might see the maximum working capacity of muscles drop. But I don't think it's the case yet that we have necessarily lost much, if any, of our strength as a species.

 

There are plenty of people who are stronger than chimps, and we can make more with relatively little effort, should they ever rebel. Conversely the lifestyle of chimps is such that they are more likely to be operating close to the maximum work potential of their muscle system, and even if they go to some kind of chimp gym I doubt they'd see significant increases in muscle size, strength, recovery speed, etc.

 

I recently got a book about muscles - can you tell? It is all jolly interesting

 

I realise this doesn't answer any of the questions pertaining to precision, but it may help to address the issue of sacrificing strength that was raised in the thread title and first paragraph of the O/P.

[Rebiu]

Chimps, Gorillas, Orangutans are not stronger than people. They all lack the powerful legs and buttocks of people. The other apes cannot compete with people in Dead lifts, squats, or cleans.

[swansont]

Strength isn't just muscle mass, it's also mechanical advantage. If the muscles/tendons attach at a different point on the bone, you will get a different torque for the same force.

 

There is also the issue of the opposibility of the thumb, which AFAIK is not a function of strength.

[reor]

I think it's rather "strength -vs- thinking". Our cognitive abilities allowed us more efficient working with less movement. Our big advantage is due to our learning ability. Isn't the neural system crutial for precision of movement?

[bombus]

Chimps, Gorillas, Orangutans are not stronger than people. They all lack the powerful legs and buttocks of people. The other apes cannot compete with people in Dead lifts, squats, or cleans.

 

Yeah, but an adult chimp can rip a mans arm off, like right OFF. Also, adult orangs and gorillas can unscrew bolts with their fingers that no man could unscrew, however strong he was. Orangutans can crush coconuts with one hand - easily.

 

A friend of mine works with gorillas and orangs in a zoo. He assures me that their arm/hand strength is far stronger than the strongest human.

 

I would venture that we probably have lost our strength, and our potential strength simply because it was not needed, and used up resources better spent on other things - like brains.

 

I think the precision argument is a good one though if it's true that apes cannot be so precise. Their hand-eye co-ordination tends to be naturally brilliant though, probably better than a well trained human gymnast, so I'm not sure.

[Sayonara]

Yeah, but an adult chimp can rip a mans arm off, like right OFF.

And I know plenty of men who could rip an adult chimp's arm off.

 

As I indicated above, human strength is not so easily generalised because we can voluntarily control our muscular proportions.

[Bluenoise]

I have a friend who works as an arborist. He spends all day swinging around in trees like a chimp except with ropes and chain saws.

 

Conseqently he's incredibly ripped.

 

He also seems to have lost alot of deterity with his hands. He now writes little better then how you'd expect a chimp too.

 

Maybe there's some truth to this.

[lucaspa]

Is the reason that humans are so much weaker than chimpanzees due, in part, to our enhanced precision of movement?

 

Are our muscles specialized not for strength, but to work in tandem with our highly complex brains to execute precision movements?

 

I've just read that no chimpanzee has ever been trained to thread a needle. Is this simply a deficiency of the chimp brain, or do its muscles also prevent it from executing such precise movements?

 

The articles here might help you answer your question:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=pubmed_DocSum&db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=9503091

 

When you have a question like this, PubMed is always the place to start.

 

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=citation&list_uids=9503091&query_hl=4&itool=pubmed_docsum

 

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=pubmed_DocSum&db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=10999274

 

This article:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=pubmed_DocSum&db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=10999274

 

Would indicate that you are correct: trading strength for precision

 

Primates. 2005 Oct;46(4):275-80. Epub 2005 Sep 6. Related Articles, Links

 

 

Muscle dimensions in the chimpanzee hand.

 

Ogihara N, Kunai T, Nakatsukasa M.

 

Laboratory of Physical Anthropology, Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, Japan. ogihara@anthro.zool.kyoto-u.ac.jp

 

We dissected the forearms and hands of a female chimpanzee and systematically recorded mass, fiber length, and physiological cross-sectional area (PCSA) of all muscles including those of intrinsic muscles that have not been reported previously. The consistency of our measurements was confirmed by comparison with the published data on chimpanzees. Comparisons of the hand musculature of the measured chimpanzee with corresponding published human data indicated that the chimpanzee has relatively larger forearm flexors but smaller thenar eminence muscles, as observed in previous studies. The interosseous muscles were also confirmed to be relatively larger in the chimpanzee. However, a new finding was that relative PCSA, which reflects a muscle's capacity to generate force, might have increased slightly in humans as a result of relatively shorter muscle fiber length. This suggests that the human intrinsic muscle architecture is relatively more adapted to dexterous manipulative functions. Shortening of the metacarpals and the intervening interosseous muscles might accordingly be a prerequisite for the evolution of human precision-grip capabilities.

[lucaspa]

And I know plenty of men who could rip an adult chimp's arm off.

 

Perhaps. But this isn't the point. It simply means that arm ripping is within the capability of both species. It doesn't say anything about relative strength. THe poster also gave several other examples where chimps and other great apes have strength capability exceeding the maximum of humans.

 

In general, chimps are much stronger than humans.

[Sayonara]

Perhaps. But this isn't the point. It simply means that arm ripping is within the capability of both species. It doesn't say anything about relative strength.

Well, that was kind of my point. I was trying to say that the simplistic and polar view of "apes have strength, humans have dexterity" is a dangerous basis for making any arguments in this thread.

 

THe poster also gave several other examples where chimps and other great apes have strength capability exceeding the maximum of humans.

Yes, in counter to Rebiu's examples of humans exceeding the maximum strength of great apes. Big deal.

When I say that I know men who could rip the arms off a chimp, I am not denying that chimps have great strength, nor am I making the claim that humans are "by default" as strong as chimps.

I am demonstrating firstly that such limb-tearing strength does not lie exclusively in the domain of the great apes, but also in that of humans, and secondly that in the case of humans such capabilities can be attained voluntarily.

 

In general, chimps are much stronger than humans.

Which, I was trying to point out, is not a useful generalisation in this discussion, since it neglects the fact that manual precision and strength are not mutually exclusive, and it also fails to take into account the voluntary plasticity of human individuals as far as both strength and dexterity go.

 

These discussions where we compare humans with animals always seem to go the same way.

 

I think this is going a bit off-center.

[intothevoidx]

Chimps, Gorillas, Orangutans are not stronger than people. They all lack the powerful legs and buttocks of people. The other apes cannot compete with people in Dead lifts, squats, or cleans.

 

I strongly disagree. A gorilla is ALOT stronger than your average human........For one their bite force is I dunno about 10-15 times stronger than your average person and they can snap a piece of bamboo a foot in diameter with ease using their arms. I just saw all of this on a show about gorillas recently. I'd like to see a human do any of that.

[Sayonara]

Right, foot down time.

 

Flat comparisons of ape/human relative strengths that do not relate to the O/P are OFF TOPIC.

[Dak]

theres broadly speeking two types of muscle: red and not-red (possibly white, or possibly white is just one type of non-red muscle, i can't remember). ok, actually that's a gross oversimplification, as there's striated and smooth (and cardiac striated) muscle, but, of the muscle that we're talking about (striated), it can be divvied up, for convienience, into red and what im going to call white.

 

red muscle is for 'raargh, me man' type strength. weight lifters have lots of it.

 

white muscle is for more explosive, rapid moovements, but is less strong and 'burns out' quickly.

 

ie, someone consisting entirely of red muscle will be relatively slow and sluggish, but really strong.

 

someone consisting entirely of white muscle will lightning fast, but have very low stamina.

 

it accounts for why big strong animals are red meat, and smaller, faster ones are white meat.

 

maybe we traded strength, not just for dexterity, but also for speed? apes seem not to be capable of as fast moovment as humans, afaict, so maybe we have less red muscle, but more white muscle, than other apes?

 

yeah, i know i could easily look this up, but im really tired so i'll leave it to someone else

[lucaspa]

Well, that was kind of my point. I was trying to say that the simplistic and polar view of "apes have strength, humans have dexterity" is a dangerous basis for making any arguments in this thread.

 

We are not talking about a simplistic or polar view. But looking at the hypothesis that, in evolution, humans traded strength for dexterity.

 

I am demonstrating firstly that such limb-tearing strength does not lie exclusively in the domain of the great apes, but also in that of humans, and secondly that in the case of humans such capabilities can be attained voluntarily.

 

But can humans voluntarily reach the maximum strength of great apes? Remember, we have 2 bell-shaped curves. The question is whether those curves come from different populations or are sampling errors from the same population.

 

I remember one incident in grad school where a monkey escaped from a cage. My fellow graduate students engaged in a Keystone cops chase thru the graduate school. Now, this primate had been caged for months -- unable to do strength exercises. The grad students, OTOH, all ran and went to the weight room. Yet, when cornered, the monkey wiped the floor with them. It took six of them to finally subdue the monkey.

 

Which, I was trying to point out, is not a useful generalisation in this discussion, since it neglects the fact that manual precision and strength are not mutually exclusive, and it also fails to take into account the voluntary plasticity of human individuals as far as both strength and dexterity go.

 

I find your objections to generality somewhat disingenuous, since you too are using generalities. I would note that I am the only one, so far, who has contributed scientific literature to this discussion. And that search turned up a paper showing differences in dexterity between humans and apes. Why didn't you do a PubMed search?

 

What you are doing is arguing the premise of the hypothesis: apes, including chimps, are stronger than humans. But instead of looking for data, you are tying to use rhetoric. Doing a quick search on ask.com, I have come up with these sites that all affirm that, in general, apes are stronger than human. The bell-shaped curves are indeed different.

 

http://www.time.com/time/magazine/article/0,9171,1541283-1,00.html

 

http://schoolweb.missouri.edu/ashland.k12.mo.us/jn/03page/webpage.htm

"Chimpanzees are both smaller and stronger than humans."

 

http://www.hsus.org/wildlife/issues_facing_wildlife/should_wild_animals_be_kept_as_pets/fact_and_fiction_monkeys_and_apes_as_pets.html

"When they begin to express their normal and instinctual behavior as they mature, monkeys and apes become extremely difficult to handle and can be up to seven times stronger than humans. "

 

Now, if you want to argue this, you would need to look at dexterity and see if apes are also as dexterous as humans. They do have opposable thumbs, after all.

[lucaspa]

theres broadly speeking two types of muscle: red and not-red (possibly white, or possibly white is just one type of non-red muscle, i can't remember). ok, actually that's a gross oversimplification, as there's striated and smooth (and cardiac striated) muscle, but, of the muscle that we're talking about (striated), it can be divvied up, for convienience, into red and what im going to call white.

 

red muscle is for 'raargh, me man' type strength. weight lifters have lots of it.

 

white muscle is for more explosive, rapid moovements, but is less strong and 'burns out' quickly.

 

You're actually looking for Type I, "slow twitch",Type IIA, "fast twitch", and Type IIB muscle. Type I is also called "red" and Type IIA is called "white". Most muscles are composed of a combination of fibers. Sprinters tend to have Type II while long-distance runners are Type I.

 

However, strength depends not on muscle fiber types but on 1) cross sectional area of the muscle and 2) moment arm of the muscle and bone. As I recall, the different anatomy of apes gives them greater moment arms. Also, short term strength (such as punching or ripping) also depends on the efficiency of anerobic metabolism. Cross sectional area can be increased by training. Moment arm is genetic, and the efficiency of anerobic metabolism would also be, to some extent, genetic.

[Sayonara]

But can humans voluntarily reach the maximum strength of great apes? Remember, we have 2 bell-shaped curves. The question is whether those curves come from different populations or are sampling errors from the same population.

Which is a question that arose after I first pointed out that the maximum strength of great apes is not necessarily always greater than the maximum strength of humans.

 

I remember one incident in grad school where a monkey escaped from a cage. My fellow graduate students engaged in a Keystone cops chase thru the graduate school. Now, this primate had been caged for months -- unable to do strength exercises. The grad students, OTOH, all ran and went to the weight room. Yet, when cornered, the monkey wiped the floor with them. It took six of them to finally subdue the monkey.

I am surprised you provided this; it doesn't sit well with the rest of your post at all. It is anecdotal and not representative of species traits.

 

Although it is amusing.

 

 

I find your objections to generality somewhat disingenuous, since you too are using generalities.

I am not trying to prove anything here, I am simply - as I often do with the meagre time I have for discussing such matters on this site - ringing a little alarm bell when I see a potentially flawed piece of reasoning being picked up and carried in a thread.

 

I would note that I am the only one, so far, who has contributed scientific literature to this discussion. And that search turned up a paper showing differences in dexterity between humans and apes.

And I thank you for it, they were very interesting.

 

Why didn't you do a PubMed search?

Largely because that is not an efficient use of my time. I am lucky if I get to log in each day and carry out my admin duties; I am hardly likely to go and do research that the thread starter is perfectly capable of.

 

What you are doing is arguing the premise of the hypothesis: apes, including chimps, are stronger than humans.

No, I am emphatically not making such an argument. I am attempting to instill the idea that the reasons why the hypothesis was being carried forward in the earlier posts in the thread might not be the right reasons, which your detailed posts have now illustrated and which is therefore no longer an issue.

[bombus]

And I know plenty of men who could rip an adult chimp's arm off.

 

I doubt it very much. I would bet that the strongest human is still weaker than your average fully grown male orangutan or gorilla.

 

Even Geoff Capes types (far stronger than so-called bodybuilders) can't crush coconuts in one hand with ease, and they could never unscrew 'industrial' bolts without tools - unlike the big apes.

[Xavier]

I would suggest that humans did not swap strength for precision, but for endurance:

 

'Monkeys' live in trees where explosive movement over short distances was useful. Humans 'came down from the trees', grew taller and changed the angle of their pelvis so they could run efficiently over longer distances over empty ground.

It has been suggested that our ancestors hunted by by endurance, like a wolf pack rather than with explosive speed, like a lion. This seems to fit with our upright posture for a vantage point, efficient running style and increasing intelligence. As weight carried is an important limit to endurance, upper body strength would be limited with respect to our tree-dwelling cousins for whom greater strength would mean greater short term speed.

 

The chimp might win at arm wrestling but the human would win a marathon.

[Sequence]

In a slight change of pace, if humans were to continue to evolve and make an even larger gap between the other ape species, would we get weaker but perhaps get to the precision/endurance that we consider only machine possible today?

[Mokele]

Xavier: you give a plausible guess at the evolutionary reason behind the differences (though I should note that human net cost of transport is the same as a chimp, and that early humans were more likely to be scavengers than hunters, at least until we made tools), but that still leaves open the issue of mechanism.

 

What matters for precision isn't the muscle size, but the number of motor units. Muscles don't contract as one. If they did, you couldn't modulate force. Instead, they have 'motor units', groups of muscle cells innervated by the same nerve. If a muscle had only two motor units, it would have only two 'settings': full force and half force - either one set of cells is active, or both are.

 

Now, when humans increase muscle cell development (since you always have the same number of muscel cells, just bigger ones if you work out), that means each motor unit generates more force, and gives a 'coarser resolution' to muscle force development. Similarly, if humans have the same number of motor units as a chimp (I have no idea if this is true or not), but each unit produces less force (and thus less total muscle force when all are active), we'd have higher precision.

 

Mokele