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Wag
 
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If we definitively want to move on to arguing something different and 'big' then we should probably move it to a different thread (I want to see how Feral responds the MtDNA/homo sapiens stuff - we can't both be right and I've sunk 3 hours of morning time into checking my grasp of theory). Language/the big brain hypothesis really deserve their own threads. I guess I'll suit words to actions and post this in a new thread then (no doubt during which time another post will have appeated in the multi-regionalism thread).
Matt Pennington (2/1/2007)
But early humans could develop precise manipulators, hands, as a clear evolutionary advantage. Those manipulators could lead to the development of a language instinct that used them. And that language instinct could then drive the development of a better communication medium - the mouth. (By going through an intermediary period in which both were used obviously).
Yes, I grasp that (with my opposable thumb!) but we don't have anything hand-wise that's obviously distinct from apes - I don't think we have developed more markedly precise manipulators (with regards sign language) than all other apes. Chimpanzees can handle sign language and yet the capacity for decent (non-grammatical) hand-based sign language hasn't spurred them towards verbal language. Why did the 'language instinct' develop in us, but not in chimpanzees? Bipedalism isn't good enough (chimpanzees have their hands 'free' during most chimp-chimp social interactions - that's how they groom).
No, unless you're just happy to wave it away with "well humans did and other apes didn't, it was just chance" (which a distressing large number of people are with lots of interesting human-only traits!) I think you have to accept that there's some other distinguishing capacity between/strong selective pressure between chimpanzees and humans - beyond 'expressive hands'. What jumps out at me is that chimpanzees can't handle anything beyond very basic mimicry but that they - as our 'nearest fellow ape' (pygmy and ordinary flavour chimp) - are better mimics than any other ape or mammal that I know (or pretty much anything beyond parrots who also share seeming language comprehension). Mimicry is a broader skill than language and you can see signs of incrementally improving mimicry in hominid evolution.
You can grunt and hoot and drive very basic sign language with operant conditioning into animals without 'advanced mimicry', but I don't see how you can have what we consider simple human languages without 'advanced mimicry'.
Moreover, between our last ape common ancestor we've clearly gained lots of vocal equipment that allows volitional speech and improves vocal articulations - but there's nothing that particularly points to improved sign language (are hands are more dextrous - but far unnecessarily dextrous for even moden sign language - chimps hands seem to be just find for that). Having accepted that (i) the gross physical and fine neural anatomy for speech is very hard to develop in it's modern form (all sorts of new architecture) and (ii) sign-language (of which other apes are anatomically capable) seems to do the 'job' - mute signers are able to communicate with eachother - then how do we avoid the conclusion that all the many millions of years sunk into developing speech weren't absolutely unnecessary - some sort of vast, hypercomplex appendix? The only way I can see is by accepting that language is an expression of what was really being selected for, not the direct trait. No doubt people did use their hands when communicating - but people who could _only_ use their hands were at a sexual selective disadvantage (much as they are today - mute deafs tend towards endogamy - to the point where they've argued for genetic engineering to select for mute deag children!).
The language instinct presupposes too much about language - the "randy mimic" hypothesis seems considerably more parisimonious to me (and it also explains directly visible hominid evolution of technology rather than just the archaeologically low-visibility stuff). Note - I haven't read Steven Pinker's book and I'm more than willing to accept that it's entirely consistent with Blackmore's "randy mimic" hypothesis.
Marios
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Wag
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Big brains bother me. The explanation of big brains seems to be that if we get an excellent fit between the data for brain size vs body mass vs intellect. Of course a large animal may require more brain to handle the larger number of nerve information being communicated to it.
Bear in mind, most comparative measures tend work in cc/volume of body - humans and a few other creatures (dolphins/elephants??) have a very high brain/body mass ratio.
Another little interesting brain tidbit from Elaine Morgan. Unlike all other ape brains human brains require a 1:1 omega-3 and omega-6 oil diet. One of those - I think it's omega-3 from cod liver oil adverts - is not found much on the interior of continents, but is found in large amounts in fish. If you don't get a decent supply of each of those oils when you're pregnant your child's brain won't develop. A very odd autamorphism (trait singular within a taxonomic category) for non-aquatic apes!
But is that really the only reason why creatures with a brain the size my partners car aren't smarter than we are just because they happen to have a body 20 times our size.
Obviously, not - big computers are not 'cleverer computers'. For brains, hardware and software aren't distinguished - size doesn't seem to matter so much - some people suffer horrendous hydroencephaly and still seem to function (semi-adequately) with a surprisingly small volume of functional brain. However, the underlying structure, as I understand it, remains.
Linking brain mass to body mass makes the problem go away.
No, I don't think it does - brain volume/body volume figures are still anomalous for some species (us, for instance).
Maybe I just don't understand it, maybe it's all transparent but if we evolved bigger brains to support our bigger intellect why aren't killer whales 20 times as smart as we are... It seems fishy to me...
Diamond was very careful to make the point that the image of 'cave man the hunter' is almost entirely fictional. Homo sapiens didn't even start pulling in the bacon in serious droves until ~50,000 - he says the majority of the diet was gathered boring stuff. I don't see how the brain could evolve to improve hunting which only seemed to noticeably significantly improve jump 100,000 years after the first anatomically modern man was found.
Bigger brains - as organs which are continually active burning sugar and oxygen even when you're not hunting/fucking/doing anything of interest - don't particularly seem to serve standard gene-only evolution. However, it's clear that they absolutely do serve memetic evolution (as does continually thinking). Sure everyone's starving and it would be great if you had to 'sit still and stop thinking' mutation, but it seems probable that a slightly less starved boring mute is a less probable sexual partner than the guy who kept everyone smiling with his endless pointless animal spirit tales (also less likely to get a bit extra of whatever food remains).
Language falls into the class of mimicked behaviour, Pinker's "Language Instinct" largely argues against this. His point is that our brains have an instinct for language, in essence that we're genetically programmed to pick it up. Part of his arguments are based on the astonishing speed with which we acquire language coupled with the fact that this acquisition phase clearly "ends". Things that are not "instinctive" (like perhaps making spears) need to be shown again and again before the viewer can learn to mimic the behaviour properly, but children acquire complex vocabulary at an astonishing speed, vastly faster than they might be expected to acquire it through simple mimicry.
Yes - sorry, I wasn't being clear. Language does fall into the class of mimicked behaviour (visibly) - that doesn't mean that we haven't _also_ developed neural hardware for assisting the mimicry of language in precisely the same way in which we've developed neural hardware to assist all other forms of mimicry.
I didn't mean to imply that language is always simply taught tabula rasa by mimicry with no supporting 'instincts/hardware' - that's rightly ridiculous. What I mean is, there needs to be a pressure to support the development of that hardware - no other creature has it despite having adequate hands for sign language. It seems likely that it grows out of some prior facility/selective pressure that no other creature has - the best candidate seems to me to be mimicry (two other creatures are known to have some level of basic mimicry - the chimpanzee with it's superlative - among animals other than us - grasp of sign language - and the parrot (I tried to find the BBC article about the parrot with a vocabulary of 100 words and a surprising grasp of grammar and protohumour - but there are just too many articles about parrots talking!)).
I would tend to agree that examining biological evidence for the ability to speak only helps you date the arrival of spoken language, not the arrival of language, which I think we both assume predates it.
I'll look out for Pinker's book - linguistics is a black hole for me, the only bits I've picked up are anthropologists talking about linguistic evidence for population movement.
Too many people automatically assume that language is somehow directly beneficial - but this seems to be pure teleology. Dunbar has gone one further and shown that it seems to replace physical grooming as a far more efficient mechanism for group bond maintenance necessary in very large groups - but he hasn't really made a strong case for why that's important. It can't be hunting, because homo erectus did not regularly kill mammoths in groups of 75 (such frequent killings only occurred well after modern form homo sapiens popped up). So why are big groups so important to primarily-gatherer hunter-gatherers? I can't help but think that we go straight back to "randy mimics" competing with language/other forms of mimicry to advance their access to sexual partners and shared resources, leading to a push for bigger groups as everyone tries to expand their social grooming network to keep up.
Marios
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Wag
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I'm going to leave the rest of this post for Matt P to reply to (since it's in reply to his post), but I think all his previous points still pertain (and Flannel's post seemed perfectly clear - in the sense of understanding rather than agreement - to me).
Flannel (2/1/2007)
Marios (2/1/2007)If there's a selective (most obviously sexual selection) pressure towards people who are more articulate (i.e. who can pick up this new and slightly more complicated language Ugobo people over the hill have started speaking) then there is a clear advantage in being equipped to handle more complex and accurate communication, but it's not in a personally improved ability to avoid rockfalls/survive childbirth. I reject the idea that selection unit is the individual. The selection unit is groups of individuals.
Group selection is theoretically mandated, but very rarely uncontentiously observed outside of creatures which reproduce as a group unit (i.e. bee hives). Mathematically, the selective advantage obtaining to a group has to be much, much greater than one obtaining to an individual to have a similar effect on gene-flow.
Flannel (2/1/2007)
Those with the facilityfor language doshare a personally improved ability to (say) avoid rockfalls. From the basic "Flee" for imminent danger of being crushed (simple concept, and not useful via sign language) to the more abstract "Don'tclimb on this branch with me it's not strong enough" (which could be conferred by sign language but only with difficulty when your hanging onto a treebut since it is more complex than 'flee' it seems likely to be a subsequent development) both confer a significant survival advantage to those groups who can communicate. the greater the degree of 'articulation' the greater the chances of survival.
Um - not much use for the one guy who has just developed the practical ability to say "don't climb on that branch". I think the selective advantage that his genes will personally gain for anything beyond the "ugh!" warning sound (already shared by other animals who never developed it further) is rather puny.
It's also important to remember that even most 'positive' mutations have some clear drawback. The development of language and the necessary anatomical features has lead us to be the only primate which suffers cot deaths and can choke on food (other creatures have their airways/foodways completely separated - as would make sense).
I'll grant that animals with basic warning cries garner a selective advantage - crucially such cries aren't speech or volitional - they still breath in and out based on CO2 levels and their cries are simply a hardwired response to certain visual/auditory/olfactory cues. None of these animals has shown any advantage in improved degrees of articulation. Creatures who 'communicate' for different reasons - ants nests/bee dances - do have a greater degree of articulation, so it doesn't seem that they for some reason couldn't evolve something better but would have been at an advantage if they did so, it seems that they didn't do it because it wasn't selectively advantageous. If it wasn't for them, why would it be for hominids?
Marios
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On the Omega-3 front, Omega-3 is found in other places than fish, notable linseeds (and most other seeds, to a lesser extent), various nuts, beans, and leafy green vegetables. The problems with Omega-3 & Omega-6 balance (which are thought to lead to depression, among other things) stem from the modern Western diet being unnaturally high in Omega-6 -- because we eat too much fried food, mostly (fried in various plant oils that are high in Omega-6).
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Wag
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Marios (2/1/2007)
No, unless you're just happy to wave it away with "well humans did and other apes didn't, it was just chance" (which a distressing large number of people are with lots of interesting human-only traits!).
I definitely don't have the answer to that and I do find your arguments somewhat convincing, but my first questions is - why didn't chimps also develop improved mimicry abilities as we did? I'm not challenging you, my grasp of these ideas is not strong enough to inform me of why groups split in the way that they do.
To put a half-and-half answer together, perhaps improved mimicry was powerful enough to allow the development of "non-complex" language. Our use of complex language is not what separates us from chimps, it's our use of any significant language at all. Sure you can teach chimps a few hundred signs and to push some buttons but they never develop these abilities unaided. They do develop the ability to use simple tools unaided and they pass those developments on, but not language.
I'd suggest that to spread effectively "simple" language, by which I mean simple concepts with little or no complex grammar or idea would indeed require highly effective mimicry skills to evolve. The chimp's ability to copy simple tool use from their fellows could be developed and put to work to create and expand an alphabet up to a few hundred words perhaps. Could that then have "allowed" for the development of areas of the brain specifically designed for language? Could the brain have developed to take proto-language to a more complex level, possibly at the same time that speech was becoming possible. I don't know, it all sounds reasonable-ish.
Moreover, between our last ape common ancestor we've clearly gained lots of vocal equipment that allows volitional speech and improves vocal articulations - but there's nothing that particularly points to improved sign language (are hands are more dextrous - but far unnecessarily dextrous for even moden sign language - chimps hands seem to be just find for that).
Your argument seems flawed, our hands have developed even more than they would need to have done for sign language so complex sign language can't have been the reason? We've also lost body hair, perhaps this was the trigger that allowed us to develop complex language while the chimps didn't?
If anything you still seem to be supporting my assertion. Chimps hands are good enough for sign language. We had chimps hands. Our brains developed to allow for simple language. Q.E.D. Simple sign language develops. Over time the increasing advantages of using sounds for our language made us develop our palate, possibly to allow for complex spoken language or possible to make complex sign language more useful (like when it's dark).
The language instinct presupposes too much about language - the "randy mimic" hypothesis seems considerably more parisimonious to me (and it also explains directly visible hominid evolution of technology rather than just the archaeologically low-visibility stuff). Note - I haven't read Steven Pinker's book and I'm more than willing to accept that it's entirely consistent with Blackmore's "randy mimic" hypothesis.
Sorry if I've mis-stated the "instinct" theory. It seems unlikely to me that the language sections of the brain lept into being (although I'm minded of the creationists argument "the eye - how could we evolve an eye!). I'm happy to accept that increasing developments in ability to mimic allowed for the development of simple language. I'm less certain it would allow for the development of complex language. Pinker is slightly convincing about the existence of the "instinct" in modern humans, buttressed by examples of language and speech loss when areas of the brain are physically damaged as well as the evidence that children do not acquire language through simple mimicry.
History is an important source for LRP. Along with other works of fiction.
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Wag
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Marios (2/1/2007)
No, I don't think it does - brain volume/body volume figures are still anomalous for some species (us, for instance).
Um yes, that's exactly my point. We divide brain volume by body volume and get a perfect straight line and the only anomalies are the exact things we would expect. We know we're smarter than chickens, so we'd expect to be much higher on the bran/body volume ratio.
So everything goes away. Except for, for me, the acceptance of dividing by body volume. I'm still unconvinced. You don't just get to divide all your results by an abitrary number and say "hey it fits the facts, it must be right". I want to know why having a large body makes you unfathomably stupid unless you brain expands in ratio. I want to know why having a huge brain is of no benefit at all if it's attached to a huge body but is extraordinarily potent when attached to a small one?
The brain/body mass division just makes me go "duh?".
History is an important source for LRP. Along with other works of fiction.
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Wag
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Matt Pennington (2/1/2007)
Flannel (2/1/2007)I reject the idea that selection unit is the individual. The selection unit is groups of individuals. Cool! A group selectionist. Marios - unleash the attack dogs!!! I've only read books by those biologists implacably opposed to group selection so I don't think I can make much of an argument of this. Suffice to say that some biologists at least pour vast quantities of scorn on the group selection idea. The fact that they are pouring it on someone, suggests that someone disagrees with them of course...
Sorry - I'll have to side with Flannel on this one (insofar as you can't disregard group selection because it's unpopular in some circles).
Group selection is unpopular because it's been used somewhat carelessly and confusedly in the past (as seems to be the case here). It's not theoretically suspect (however if you work through the mathematics you'll see that, for a given selective pressure, it will always have a much weaker/slower effect on gene frequencies/mutation selection than individual selection) - it's part of the main-stream 'selfish gene' synthesis (a gene is defined as a unit of selection - not as bits of DNA what code for one enzyme, that's a hackneyed (but simple and understandable) old idea from early 1900's molecular biology) - you can talk about multiple gene-complexes as genes, you can talk about genes in different organisms being simultaneously selected for (bees) - you can even talking about species selection (do the maths - you'd need to observe an awful lot of species extinctions to be able to conclude on any significant species selective pressures).
It's unpopular not because it's stupid (it isn't), but because stupid people often make recourse to it not realising the distinctions or limitations between individual selection and group selection.
Crucially, there's a tiered comparison here. Group selection is weaker/will operate slower than individual selection. (standard) Individual selection is weaker/will operate slower than sexual selection (which is often more comparable to 'first past the post' - Jimmy has a visible positive trait which make him .2% more likely to survive, Johnny doesn't - sexual selection aside it's going to be a long time before Jimmy beneficial traits blees through the population - however, if the trait is sexually selected for it may now effectively cause a 50-90% greater chance of being represented in the next generation. This is where the term "runaway sexual selection" comes from.
Ian Sturrock (2/1/2007)
On the Omega-3 front, Omega-3 is found in other places than fish, notable linseeds (and most other seeds, to a lesser extent), various nuts, beans, and leafy green vegetables. The problems with Omega-3 & Omega-6 balance (which are thought to lead to depression, among other things) stem from the modern Western diet being unnaturally high in Omega-6 -- because we eat too much fried food, mostly (fried in various plant oils that are high in Omega-6).
Elaine Morgan was talking about hominids pre-australopithecus. She didn't say omega-3 is only found in fish, she said it was plentiful in fish, notably hard to get hold in the interiors of continents (I assumed she wasn't just saying that fish are hard to get hold in the interiors of continents, but also that other omega-3 containing compounds - and possibly being more specific to Africa). I'll check the book for a direct quote.
Elaine Morgan quotes Robert Martin (maternal energy hypothesis):
http://physiologyonline.physiology.org/cgi/content/abstract/11/4/149
And Michael Crawford ("The Driving Force").
"The omega 3 type is plentiful in the sea food chain, but scarce in the land food chain, especially in the interiors of continents."
Marios
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