Profound articles of interest

[BainbridgeShred]

I missed you Jeremy!

Ken's right in that Dan missed the point, on almost everything he wrote. I don't think it's nit-picky, but rather I made completely different points to what you thought I was making.

I think Ken's problem (My problem) was that he thought I was saying humans needed meat or they simply wouldn't survive. Obviously, anyone with a brain knows that the majority of people on the planet survive on nothing but grains with absolutely no meat, so somewhere between my wording being bad and Ken being nit-picky is where the problems arose.

Bullshit. Provide some evidence for this claim please. It's clearly not "well accepted" at all. There are actually multiple competing and complimentary theories about why our brain development is so big - tool use, cooking, increased life spans, increased social behaviour due to decreased time needed to search for food, development of language, etc. Yes there are people who think it was an increase of meat in our diet, but that's not the accept view at all - the issue is still widely debated.

Hahahaha no you don't understand dude... It would be physiologically impossible for humans to have simply "grown a bigger brain" thanks to tool use, cooking, increased life spans, or increased social behavior (Of which the use of language can be lumped in to). In order to set the stage for the development of such an energy intensive organ as the brain seen in homo sapiens, we would have needed an abundant and highly calorie/nutrient rich energy source or our metabolism's never would've supported the growth of such a organ.

I'll respond to your other points when I have more time, but I'll ask again, if eating meat is a dilemma to you, then why do you choice to do it? Asked another way, what are we arguing here if we both already agree that meat is beneficial on some level in the human diet. Are we simply arguing over what degree meat should be allowed in the diet, because if so we're moving quickly in to the field of intellectual masturbation. As I've said, the hundreds of millions of people who survive on rice alone makes it clear that my original point wasn't "Every human needs to eat meat or they're going to die by 30", and judging from the fact that you consume meat, I don't think your point is "Meat is bad for you" either.

So just for clarity's sake, is your argument simply that we should eat meat, but not that much?

[Allan]

Hahahaha no you don't understand dude... It would be physiologically impossible for humans to have simply "grown a bigger brain" thanks to tool use, cooking, increased life spans, or increased social behavior (Of which the use of language can be lumped in to). In order to set the stage for the development of such an energy intensive organ as the brain seen in homo sapiens, we would have needed an abundant and highly calorie/nutrient rich energy source or our metabolism's never would've supported the growth of such a organ.

You might want to be careful about making blanket statements about things that, as Jeremy says, are still intensely debated in the scientific community. An apt and current example:

http://blogs.scientificamerican.com/gue ... be-so-big/


I'm not saying that you're necessarily entirely wrong about meat-eating leading to larger brains (it might have contributed in some way), but it's certainly not the consensus on the issue (I don't think there is a true consensus), and the matter is definitely far from settled.

I'll also note that in studying anthropology (granted not exclusively, but I took a half-dozen 101 classes and a couple 2nd year) for two years, the "meat-eating definitely lead to larger brains" hypothesis was not mentioned in any notable fashion (if at all) in any of my text books or by any of my professors.

[C-Fan]

I'm assuming those were Canadian Universities, and therefore do not count in Dan's book.

[BainbridgeShred]

Alan... I'm not sure you understood the point of your article, because it very much supports my original hypothesis about how consuming animal products could have correlated to a growth in human brain size and cognition... The "expensive tissue hypothesis", which your article is about, is one of the theories on which many in the paleo/meat heavy community rely upon. Indeed, the "expensive tissue hypothesis" is founded upon the idea that a high quality diet allowed for a smaller, less energy consuming guts, and thus allowed for a larger, more energy consuming brain. Now, the original authors of the E.T.H., being much better scientists than me, don't come out and say that "meat WAS the high quality diet that allowed for smaller guts and larger brains", but it seems likely that it was.

But if anyone has any better ideas (And by better I don't mean "language 'n toolz made r brainz real real big) on how humans were able to achieve such a high level of cognition and brain size 100,000 years ago, I'd love to hear them. From the research I've seen, the only hypothesis that makes sense is that a new found access to bone marrow allowed our bodies to free up energy previously used in digestion and diverted it to developing cognitive functions.

I'm not saying that you're necessarily entirely wrong about meat-eating leading to larger brains

I'm being nit-picky here, but I never argued that meat led to larger brains; simply that eating bone marrow led to larger brains.

Regardless, any explanation of human brain size and capability is extremely lacking if it doesn't take calories into account. Jeremy's theories about language use or tool use leading to a growth in brain size is like saying an egg lays chicken-- AKA complete hogwash. The theories don't work because they don't explain where the energy came from to power an organ that, as your article said (And as I said earlier), makes up only 2% of our body mass but consumes more than 20% of our oxygen supply and blood flow.

[Allan]

Oh, I understood the article just fine, thanks.

[BainbridgeShred]

Well, it's clear from your original post that you don't/didn't.

Exhibit A:

I'm not saying that you're necessarily entirely wrong about meat-eating leading to larger brains (it might have contributed in some way), but it's certainly not the consensus on the issue (I don't think there is a true consensus), and the matter is definitely far from settled.

Exhibit B: You then went on to post a hypothesis that most people use to argue for the fact that meat/marrow WAS what led to our growth in cognition and brain size, while presenting it as if it were a competing hypothesis, when the two are not at all mutually exclusive.

At least the Dan Man can admit when he's been unclear/wrong about something (As I often am; as you all know from arguing with me when I was 14 years old )

Edit:

the "meat-eating definitely lead to larger brains" hypothesis was not mentioned in any notable fashion (if at all) in any of my text books or by any of my professors.

As Ken pointed out, I can't be held responsible for the state of the Canadian public education system. Had you been a hundred miles south in Seattle where I studied biological anthropology, you would have been introduced to the bone marrow hypothesis repeatedly, for the very reason that it's the only solid explanation for the exponential growth of the human brain that occurred in proto-homo sapiens. As I'll say again, if you have a competing hypothesis lets hear it, because so far you've only posted an article that supports my position...

[BainbridgeShred]

double post, plz delete mod

[BainbridgeShred]

triple post, plz delete mod. im rusty on the phpbb forums

[Jeremy]

Thanks Allan.

What's really noticeable about your article and what Dan wrote before is this;

In the 8 million to 6 million years since the ancestors of humans and chimps went their separate ways, the human brain more than tripled in size. If the earliest humans had brains the size of oranges, today’s human brains are more akin to cantaloupes.

Also, fire is not at all a recent invention, and certainly predates modern Homo Sapiens by AT LEAST 200,000 years, which is longer than we've even been on the planet. Please dude, if you're going to argue this shit with me you need to go take a evolutionary anthropology class or something. This is basic shit...


Tropical fruits alone wouldn't have given humans of 150,000-200,000 years ago enough of a nutrient surplus to become what we are today. You need to go back and study your biological anthropology, because this is really 101 type shit.

This comes back to the point I made in my last post, which is that the evolution we're talking about is long term evolution - millions of years, not evolution that has occurred in the last half a million, and we can see that if Dan's comments about fire are correct, then clearly the brain expansion had started before the use of fire. Given the similarities in diet, teeth and digestive system, between our nearest ancestors, I'd argue that we really need to go back beyond our nearest relatives to understand how our eating habits developed. As I've stated, evolution is not a reason for doing things now, only for understanding why we currently do things, or did things.



If we want to talk about alternative theories, here is one, that has been cited about 700 times since publication;

The Social Brain Hypothesis by Dunbar RIM (British, unfortunately, but current professor of Evolutionary Anthropology at Oxford, which despite not being American, has probably at least been heard of by Americans);
http://archives.evergreen.edu/webpages/ ... hrop_6.pdf


Geofrey Miller (American evolutionary psychologist) wrote a book called "The Mating Mind" arguing that our brain size developed due to sexual selection and a positive feedback loop, which is a claim Richard Dawkins has also written about, at least in passing, a few times.


This is a very famous paper by Flinn, Geary, and Ward (all from the University of Columbia, US) published in Evolution and Human Behaviour (2005) in which they created the "Ecological dominance-social competition" model, which I would have thought is the leading explanation these days, based on some previous work by Richard Alexander (another American evolutionary biologist).

http://web.missouri.edu/~gearyd/Flinnetal2005.pdf

[Jeremy]

A quote from the introduction of Flinn, Geary & Ward;

Many hypotheses have been proposed concerning the selective advantages of cognitive change during human evolutionary history. Most explanations involve ecological problem solving, such as tool use (e.g., Darwin, 1871; Gibson & Ingold, 1993; Washburn, 1959; Wynn, 1988), hunting (e.g., Dart, 1925; Hill, 1982;Washburn & Lancaster, 1968), scavenging (e.g., Blumenschine & Cavallo, 1992), foraging (e.g., Isaac, 1978; Kaplan, Hill, Lancaster, & Hurtado, 2000), extended life history (e.g., van Schaik & Deaner, 2003), food processing (e.g.,Wrangham, Jones, Laden, Pilbeam,&Conklin-Brittain, 1999), and savanna (e.g., Laporte & Zihlman, 1983) or unstable (Potts, 1998; Vrba, 1995) environments. None has achieved complete or general acceptance, even when combined in synthetic models and causally linked to social dynamics.

[C-Fan]

This is a very famous paper by Flinn, Geary, and Ward (all from the University of Columbia, US) ...

Doesn't sound very American to me. Dan, you should go ahead and ignore that study too.

[Outsider]

I have only been skimming the most recent posts in this topic, but this latest issue of the factors that lead to a larger brain in human ancestors caught my eye.

I USED to be a scholar of this topic, and still follow the news tid-bits that reach the general public. I thought one of the most interesting ideas to arrise lately had to do with a single simple genetic change effecting the jaw muscles of human ancestors:

http://www.nytimes.com/2004/03/25/us/le ... all&src=pm

I have not now re-read this article, so I am summarizing from memory from five or six years back, but the idea goes something like this:

One major impedement to the expansion of the human brain is the thickness of the austrolopithecine/homo skull. Human ancestors, like modern chimps and gorillas, had to consume mostly uncooked plant matter, which required a huge amount of CHEWING (needed in part just to get all that tough plant fiber down the throat, and also because all that tough plant fiber does not digest well unless it is well-chewed). The large jaw muscles needed for this were also necessary to consume tough-shelled nuts. So, strong jaw muscles were needed for our diet. Strong jaw muscles required thicker tougher skull bones for those big muscles to be anchored to. A smaller skull is also a sturdier stronger structure for these large jaw muscles. So, small thick skulls were essential otherwise the force generated by big jaw muscles could break the bones of our skull (I've heard that ape jaw muscles are comparable to human quadricep leg muscles -- much bigger and stronger than modern human jaw muscles). And smaller thicker skulls constrained brain growth. Your brain simply had nowhere to expand if our need to chew lots of tough nuts and uncooked leaves required us to have small thick skull bones. Thinner larger skulls would not be tough-enough to support the big jaw muscles we needed for all that chewing and nut cracking.

So, smaller weaker jaw muscles opened an evolutionary door for brains to grow larger because smaller weaker jaw muscles mean that we no longer have an absolute need for a small thick sturdy skull to anchor those big jaw muscles to.

Now, a genetic mutation leading to smaller weaker jaw muscles for a vegetarian species would seem like a big genetic DISADVANTAGE that should fail to be carried on in the gene pool, except that our earlier austrolopethicine and homo habilus ancestors were already above-average intelligence and could use some basic tools and perhaps also fire to cook food. So, we became worse at chewing our food but it didn't count against us because technology (tools and fire) reduced our need to chew -- the tools and the first did some of the "chewing and digesting" for us, so the smaller weaker jaws were not a real disadvantage.

Now, this doesn't necessarily speak for or against eating meat -- in fact, it could be seen as dovetailing-in with the meat and marrow idea. Marrow, after all, is hard to get at without tool use (unless you have a jaw like a hyena, which can easily chew through bones). Whats more, the tool-use that gave us access to marrow basically gave us access to a rich food source that was largely unavailable to alot of our competition -- hyenas can chew through bone, but not all other predators can, so we could harvest a cheeta's left-over bones. And meat, over all, is more easily eaten and digested when cooked. But then again, so is alot of plant-matter. And once you can get nuts out of tough shells by smashing them with a rock, why would you ever go back to cracking them open with your own teeth?

I guess the real point is that, regardless of what we were eating, expansion of our brains may have essentially been prevented by our own muscle and bone structures until a genetic mutation removed that structural obstacle, and our mastery of primitive tools meant that the genetic mutation wasn't the disadvantage it otherwise would have been. So, smaller weaker jaw muscles allowed for thinner larger skull bones, which allowed for a larger brain, which resulted in ever greater use of technologies.

So, my point really is that there are some other plausible hypotheses for what lead to/contributed to the expansion of our brains. It doesn't all simply depend on meat. Meat is just one piece of that puzzle, and perhaps not even the most critical piece (that is, if not for the genetic mutation leading to smaller weaker jaw muscles, our large strong jaw muscles would have required our skulls to stay small and thick, cutting off our avenue to expanding brains no matter how much meat we ate).

Anyway, I just really liked this "smaller jaw muscle" idea when I first heard about it a few years ago, and wanted to add it to this discussion.

Thanks.

further reading:

http://www.upenn.edu/pennnews/current/node/2308

http://creation.com/images/pdfs/tj/j19_ ... _88-96.pdf

[BainbridgeShred]

Lol... C'mon Jeremy... Of course evolutionary pressure had been selecting for bigger brains since the first Australopithecus' began walking around on two feet. Big jumps occurred with Homo habilis (Literally, handy-man) and Homo erectus, who are pretty closely related to Homo sapiens. So, lets compare brain sizes. Actually before we do let me clarify for the nit-picker trinity out there that big brain size does not necessarily = intelligence. Let me also mention that the figures below are averages, and that Archeology is a pretty soft science.

Chimpanzee: 400 cc

Homo habilis: 600 cc

Homo erectus: 1000 cc

Modern Homo sapien: 1300 cc

Do you guys need a picture too? I'll copy and paste myself: Of course evolutionary pressure had been selecting for bigger and more complex brains since the first Australopithecus species began walking around on two feet, and before that. So who knows exactly which Hominid species was the first one to start cracking open bones and sucking out the marrow. My guess is around Homo habilis, give or take a species or two. Now, this doesn't necessarily prove that bone marrow and banana's are an ideal diet for modern humans of today, but thankfully it's been suggested by studies that both are very nutritious.

So let me make myself clear Jeremy, because you seem unable to grasp some basic concepts. It isn't that Homo neanderthalis discovered how to crack bones and all of a sudden Homo sapiens came out of no where with all these amazing cognitive abilities and the means to control fire and hunt huge herds of mammoths. The Hominid evolutionary process was a very gradual one that culminated with us. Like I said, fire and the bone marrow trick were probably figured out by Homo habilis. By Homo neanderthalis we were hunting huge herds of game, and rcheologists have speculated that Homo neanderthalis tribes were also taking care of the injured and sick, (So soft science archeologists say). This was supposedly shown by the find of a Neanderthal man's femur that they contend was fractured sometime early in his life, and despite this injury the man lived to maturity. Again Archeology is pretty suspect so who knows but these guys are experts in their field at least so I teeeeend to trust some of them. Regardless, the trend I am spelling out for you is one of nature selecting for bigger and more complex brains over a VEEERY long time.

So why have I gone on this diatribe? To make it clear that yes, tool making and language definitely helped shape the structure of the brain, but that these changes MOSTLY occurred AFTER an abundant and nutritious calorie source was found. This had to have been the case or our metabolisms could not have supported the gradual development of an organ like the brain. I contend that the new calorie source was the marrow inside of scavenged animal bones; along with all the things we use to eat prior i.e. fruits/insects/lizards/frogs/birds. This is also why all of these things are still extremely nutritious for us (Although fructose does have some issues of its own, I personally eat 4-5 pieces of fruit a day and think its fine). So Jeremy's point as far as I can garner (And correct me if I'm wrong) is that the things we've been eating since Australopithecus days are better for us than the things we've been eating since Homo habilis days. Unfortunately, this hypothesis is based PURELY on observation, and is the same mistake Paleo people make when they argue that because grains are only 10,000 years old they must be worse for humans than meat and fruit and nuts. Their is nothing in evolution that says a species can't be pre-adapted to a new food source, and their is nothing in evolution that says the new food source is inherently less nutritious than whatever the old food source is. Game, set, match.

I'd argue that we really need to go back beyond our nearest relatives to understand how our eating habits developed.

As I just said above, yes the thing that our distant ancestors ate tend to be good for the most part too, i.e. bugs/small game/fruit. You made fun of me earlier for mentioning eating bugs/lizards in a conversation about humans evolving to eat ruminants and such, but that just shows how ignorant you are when it comes to evolution and nutrition, because the one can pre-adapt and reinforce the behaviors of another.



Edit: Where is this "Dan hates Canadian's" nonsense coming from? I get most of my nutrtion information from Mat LaLonde, whose video I posted early in this thread. He's a Canadian who studied Organic Chemistry at Harvard, because why study it at the University of Toronto when you can go to Harvard.

Besides America, I can't imagine a country in the world that I'd rather live in than Canada (Oh and besides New Zealand if they'd take me). If I were to dislike Canada and Canadian's, I'd essentially be disliking America and American's.

And Canada is just finally starting to be a baller and assert itself. Their economy is going pretty dang strong, and if they'd only get over the whole Keystone XL thing then I'd really want to kiss them on both cheeks.

[BainbridgeShred]

Now, this doesn't necessarily speak for or against eating meat -- in fact, it could be seen as dovetailing-in with the meat and marrow idea.

Well, that's what I was thinking when reading your post. Bone marrow is certainly a slushy substance, and cooked meat is also very easy to chew and swallow. But, if this hypothesis about increased in brain size being the result of humans eating softer foods were true, it could also possibly be the result of ecological changes that increased the abundance of fruit and insects in tropical Africa, which of course are also easy, and indeed easier, to chew than either raw or cooked meat. It seems unlikely to me that this is the case so I'm going to stick to my bone marrow hypothesis, but hey theirs nothing wrong with developing competing hypotheses.

In a somewhat related note, I once read a interesting paper that contended that modern human malocclusion (Misalignment of teeth requiring braces and such) is the result of modern babies not being introduced early enough to cooked meat, which is tender yet tough and allows the baby to exercise their jaws and form their gums or something or other. That's what this Anthroplogical Orthodonist who wrote the paper was arguing anyways (Just kidding, I forget who exactly the dude was)

[Jeremy]

So Jeremy's point as far as I can garner (And correct me if I'm wrong) is that the things we've been eating since Australopithecus days are better for us than the things we've been eating since Homo habilis days.

You're wrong.

In fact, could you please quote what I've said that made you think this was my point?

This doesn't give us a reason to eat, or not eat meat. It's false to say that evolution suggests we are 'supposed' to do anything. Our biology tells us that we can eat meat, that we shouldn't eat too much, and that we don't have to.

if you split the meat eaters up into those that eat balanced diets and get regular exercise and those who don't, the healthy meat eaters live longer than the same grouping of vegetarians (essentially eating a small amount of meat in a balanced diet, and getting plenty of exercise, is the healthiest lifestyle a person can have).

As I've stated, evolution is not a reason for doing things now, only for understanding why we currently do things, or did things.

etc.

Edit;
And let's not lose cite of the claim from your amazing article that this is all critiquing - relating to why we should eat meat;

Lions and hyenas and humans don’t have a ruminant’s digestive system. Literally from our teeth to our rectums we are designed for meat.

I also note you still have provided any evidence at all that your bone marrow hypothesis is the most widely accepted explanation for brain growth. Do you actually have any evidence for that, or are you making it up? I note that everybody else can provide evidence for their claims, except you...

[BainbridgeShred]

Jeremy:

I'd argue that we really need to go back beyond our nearest relatives to understand how our eating habits developed.

While this assertion isn't wrong, it is such an obvious assertion that the implicit message is that "the things we ate a long time ago are better than the things we've only started to eat recently". I can't imagine why else you would make such an obvious claim.

Our biology tells us that we can eat meat, that we shouldn't eat too much, and that we don't have to.

It's on the "shouldn't eat too much" part of that sentence where this argument boils down. I don't think their is anything wrong with eating meat most days of the week at least once a day, and indeed think that it's a pretty good idea assuming you're living a very active lifestyle. You still need to define what "too much meat" means to you.

I also note you still have provided any evidence at all that your bone marrow hypothesis is the most widely accepted explanation for brain growth.

Oh Jeremy, be patient my friend. I told you I would go back and respond to the points you made in your post on the last page, and I will when I have a bit more time. You could do me the same favor if you care to, because right now you're nit-picking certain parts of my posts without answering the bigger questions such as:

What was the calorie source that allowed our brains to go from 300-500 when we were largely vegetarians, to the big jump in size difference we see between Homo habilis and Homo erectus (A jump from 600 to 1000 in cc). Remember, many Australopithecus and Homo species lived for millions of years before Homo sapiens came along, and one of the most evolutionary fit Australopithecus species was Australopithecus afernsis, who had a brain size very similar to that of a Chimps. So what accounts for the relatively rapid jump in brain size we see when we look at Homo habilis (600 cc) going to Homo erectus (1000 cc) to Homo sapiens (1300 cc)?

I contend that the access to the new found food source of bone marrow set the stage for the rapid increase in brain size, and was co-influenced by processes that were already in development, such as tool use and communication/language progressions.

What do you contend Jeremy when it comes to what it was that allowed for the rapid increase in brain size in the later Hominid species? You might find it's a bit harder taking an actual stand on what hypothesis you think is correct, instead of being a typical postmodern vagine and sticking to nit-picking others arguments. Your a Hitchen's fan, so you can't possibly take my accusation of you being a PoMoVaGi as a compliment can you?

[Jeremy]

Still no references hey?

When you say;

It's pretty well accepted today that what allowed humans brains to grow to the size they are today was the scavenging of meat on the African Savannah, specifically cracking the bones of prey animals with crude tools, and sucking the bone marrow out.

Then surely it should be easy for you to provide evidence that it is widely accepted, because there should be a wide amount of evidence?

Instead, when I read through my books on anthropology, when I look at wikipedia, when I do google scholar searches, and when I read through the most cited articles on that question, which I've quoted for you, I continually see this;

[No theory] has achieved complete or general acceptance.

Did you make up the claim that your theory is widely accepted, or am I just looking in the wrong places?

[BainbridgeShred]

I got the information from my biological anthropology professor from years and years ago, Pete Knutson, Ph.D, Stanford. I took the class in 2009.

Edit: Scratch that, he got kicked out of Stanford after studying there for three years, and finished his degree and got his Ph.D at the University of Washington.

Interesting side note, he got kicked out of Stanford because he snuck into some department on campus and stole some designs by the company Honeywell (Who are known for making thermostats) to build a bomb designed to hit the ground and then explode a few minutes later once civilians and soldiers gathered around. Interesting article about him here http://news.stanford.edu/pr/92/920501Arc2243.html

But ya, it is through him that I am saying that what fueled the jump in human brain size in later hominids was the largely thanks to the access in bone marrow.

[Jeremy]

So it's an anecdote, and you can't find a published source?

Do you therefore agree or disagree with Flinn, Geary & Ward (2005), and also me, when they say;

[No theory] has achieved complete or general acceptance.

or when I say

Yes there are people who think it was an increase of meat in our diet, but that's not the accepted view at all - the issue is still widely debated.

Or do you stick with your anecdote over the peer reviewed published assessment?

[BainbridgeShred]

Again with this? Just because I support one hypothesis over another doesn't mean that Flinn, Geary & Ward are wrong in saying that no theory has gained complete acceptance. It just means that a lot of smart people have different thoughts on how it all went down, and to me, the bone marrow hypothesis seems pretty solid. It certainly wasn't the only thing the was increasing brain size- as I said that had been going on previously, but not at as fast a rate until you reached Homo habilis.

Supporting a hypothesis and accepting that it could be wrong is all part of the game and I don't know why I'm having to explain this.

I have yet to even do a Google search on bone marrow and its effect on evolution. I would hardly call the words of a renowned Ph.D in anthropology an anecdote though.