Your theory that cooking spurred the evolution of modern humans occurred to you while you were sitting in front of your own fireplace?
Yes, about 10 years ago, right after the start of the academic term, I was thinking about what stimulated human evolution. The fire just started drawing me in to the comparison with chimps, because I tend to think about human evolution through the lens of chimps: What would it take to convert a chimpanzeelike ancestor into a human? And as I thought about how long we have had fire, I realized what a ridiculously large difference cooking would make. It's a very simple thought; anyone who had ever taken an anthropology course should have had it long before this.
Just how would cooking make a difference? What's wrong with raw food that chimps eat?
I know chimpanzee foods fairly intimately, I've tasted the great majority of the things I've seen them eat, and I know what a huge difference there is between a chimpanzee diet and the human diet, because we cook. And that set me off thinking about whether or not humans really could ever survive on a raw diet. And my instant assumption was no, because of my experience with chimpanzee diets, which said to me we couldn't possibly do this—so that raises all these fascinating evolutionary questions. I'd had the experience of seeing a close relative eating all those foods and seeing how unpleasant they are and how difficult it would be for humans to survive on a diet like that. Maybe people assume that the kinds of places in which humans live would have apples and bananas dripping off the trees, but it's not like that.
What are the foods like, then?
The typical fruit is very unpleasant, very fibrous, quite bitter; the net effect is that you would not want to eat more than two or three of them before running for a big glass of water and saying, "That was not a pleasant experiment, I hope I don't get sick." They're not nice to eat. Not a tremendous amount of sugar in them. So there were very few fruits that I've tasted that I can actually imagine getting a stomach for because most of them are unpleasant to eat. Some make your stomach heave.
But maybe if we—or ancient humans—were accustomed to them, we would be able to eat them.
I recognize that I've got a palate softened by ease, and it may well be that if you're hungry in the bush you might be prepared to eat a lot of these nasty tasting things, but I've worked with Pygmies in eastern Congo in a forest where I knew a fair number of fruits were being eaten by chimps, and I would ask them, and they'd say there's no way I would ever eat this stuff. Chimpanzees eat, on average, 60 percent of their food as fruit. Humans couldn't do that. So one of the fascinating things for me as I ventured into this was really learning about what hunters and gatherers eat—and it turns out that there are no records of people having a large amount of their food come from raw food. Everywhere, everyone expects a cooked meal every evening.
What about the way our bodies are set up to digest food—besides not liking the taste, can we digest the foods chimps eat?
I think we can probably digest them—this is guesswork because we don't really know—but the point is they're very full of indigestible fiber. So the average human diet has, even in the more fibrous hunter-gatherer types, 5 to 10 percent, say, indigestible fiber. With our chimp studies, they eat 32 percent indigestible fiber. So that is something that the human body is not designed to handle. And the reason we can say that is that we have small colons and small stomachs which are adapted to food that has high caloric density. And food the chimps eat has low caloric density.
When you looked at the archaeological evidence, what were the clues that indicated to you that fire spurred the development of Homo erectus?
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Add CommentI lived on an all raw (totally uncooked) vegan diet for 2 years. I know a number of people that have done this for longer. There are children raised this way. They do just fine. They don't tend to be obese, but they are fine. My girlfriend loves raw meat and eats it. Raw fish is quite nice as well.
Reply | Report Abuse | Link to thisA seafood/shellfish and perhaps turtle mainstay diet makes sense for supporting brain growth. But most of this speculation about brain size and energy requirements just falls on its face when one looks at the facts. Truth is, humans can and do eat almost anything and survive well. And it doesn't harm their brains.
I don't think he's saying that the modern raw vegan diet is unhealthy. In fact it certainly is healthier than the fatty fast food many people today consume! However, the modern raw food vegan diet still involves a lot of processing, and abundant food sources, to be successful. Our ancesters didn't have access to blenders, food processors, or even the larget variety of food we have 365 days a year at the grocery store.
Reply | Report Abuse | Link to thisWrangham's hypothesis is that cooking would have been greatly beneficial to early humans. Some people have tried to counter this argument by appealing to their personal experiences subsisting off of raw foods. Its important to remember that modern folks live in a world of agriculture, refrigeration, and supermarkets. People who today subsist on raw foods rely upon these and other things which were unavailable to early hominids. Show me a hunter gatherer that lives off of entirely raw foods, and I would take these types of arguments seriously. But their aren't any. That's called survival of the fittest.
Reply | Report Abuse | Link to thisAgreed. Attempting to disprove a theory based on personal anecdotal experiences accomplishes nothing. A modern human who already posses an evolved brain will not "de-evolve" if he does not subsist off a cooked diet for a short period of time.
Reply | Report Abuse | Link to thisConsider the logic presented.
Reply | Report Abuse | Link to this1. Our brains require a lot of energy. Therefore we need more energy providing foods to support them.
2. The amount of energy required to support a larger brain would be so great that evolution to a larger brain size could not have occurred.
3. That the availabilty of cooked foods made larger brains possible, and that somehow liberated our brains to grow.
Let's take each proposition/assumption in turn:
1. Large brains take a lot of energy.
Let's look at the numbers.
http://bja.oxfordjournals.org/cgi/content/citation/47/2/143
The human brain needs 100-150 grams of glucose per day. This is approximately 500-600 kcal per day.
Let's compare that with muscle. 1 lb of muscle that is not used, burns about 20 kcal per day. In a human body, at rest, with roughly 80 lbs of muscle, that's a resting requirement of about 2,000 kcal. But when we exert ourselves (or any animal does) we can burn as much as 7000 kcal per day more than that. (Heavy farm labor.)
Human brains vary in size (for Nobel laureate geniuses) by 100%. From 1000 cc to 2000 cc, averaging around 1400. Chimpanzees are around 400 cc. So chimpanzee brain requirements are, on our low end of (genius) brain size 40% of ours. The [i]difference[/i], then, is [i]about 300[/i] [i]kcal[/i] per day. That's [u]three bananas[/u].
Chimpanzees are pretty active. Their caloric requirements are around 3000 kcal (resting) to 6000 kcal(quite active) per day. Can they afford 3 bananas per day more food required?
2. Amount of energy required for the extra brain would be so great that it could not have occurred without cooked foods.
Evolution is a negative selection process on chance events. The proper calculus is weighing benefit versus cost. Gorillas maintain much greater caloric cost muscular bodies than our 3 extra bananas per day worth of brain. Adult male gorillas need 8000 kcal per day. http://www.nagonline.net/Diets%20pdf/Gorilla%20Nutrition.pdf
For evolution to eliminate something, the cost of the feature must be great enough to prevent adequate reproduction within a niche. Clearly, there is a wide range of possibilities and that's just within the primates. Gorillas eat a diet of 68%-70% leaves. They get enough calories.
So the proper question is, was this small difference in energy requirements worth the cost? Comparing us to gorillas and chimpanzees, it would seem so. Bigger, smarter brains made us able to expand our range of foods and find more rich food sources.
3. The idea that our brains were liberated to grow by availability of cooked foods is backwards.
If we had larger brains, then some genius could figure out how fire worked. That would let us find out we can cook things, and that, in turn, would lead to evolution allowing people with smaller jaws, teeth and gut to survive. But the [u]major difference is not in the amount of calories per day[/u], not in hunter-gatherer situations. The [u]major difference is in the[/u] [u]amount of time spent eating each day[/u]. Chimps spend 6-10 hours a day eating. We can get by with 2-3. That is a huge advantage - if you have a brain that can take advantage of it. Among other things, it gave us time to spend agriculture and the myriad other activities that make us human.
But cooked food enabling our evolution of brain size? It doesn't stand up.
"it gave us time to spend agriculture and the myriad other activities that make us human."
Reply | Report Abuse | Link to thisSo hunter gatherers, those without agriculture, aren't human? I beg to differ.
"So hunter gatherers, those without agriculture, aren't human? I beg to differ." -Brianwood1
Reply | Report Abuse | Link to this"it gave us [u]time[/u] to spend agriculture [u]and the myriad other activities t[/u]hat make us human."
Evolving Bigger Brains through Cooking
Reply | Report Abuse | Link to thisCooking allows us to have a simplified digestive system, or to put it simply a smaller belly. The resources that would have gone to build the belly can now be used elsewhere.
The brain has a cost, it also has benefits for the owner. The brain has to pay for itself.
The big brain is beneficial in the case of global warming (or cooling) as people have to adapt rapidly to evolving ecosystems. If you have a big brain you have less to fear from global warming because you can adapt more rapidly. The unstable climate of the last 2 million years created an ecological niche where a big brain animal had an advantage. It is more efficient to solve a problem using software than using hardware.
In evolution there is a push and a pull. The push is the availability of resources to create a bigger brain, the pull is the usefulness of the bigger brain. Both should exist.
Credits for a big brain should also be given to the fact that we are wearing clothes. Along with cooking, clothing is mans greatest invention. With clothing we can do away with body hair and the resources that would have gone to grow hair can now be used to grow a bigger brain. Growing and grooming fir uses a lot of resources.
Furthermore with warm clothes man was able to migrate out of Africa where it had evolved with its parasites. Outside Africa the environment is healthier and the resources used to fight disease can then be used to grow a bigger brain.
In the days of the hunter gatherer you needed a large area to sustain a tribe. By moving to new territories you increased the availability of foodstuff, so you could afford a bigger brain.
Clothing is part of our heritage to such an extent that even at the beach we have to wear some clothing. This is why generally people do not appreciate how much we owe to clothing.
I favor the shell-fish first hypothesis. Then bigger brains and smaller guts. Then fire. Then still bigger brains, etc.
Reply | Report Abuse | Link to thisinteresting idea
Reply | Report Abuse | Link to this--
Edited by franke at 12/28/2007 9:33 AM
> I lived on an all raw (totally uncooked) vegan diet
Reply | Report Abuse | Link to this> for 2 years. I know a number of people that have done
> this for longer. There are children raised this way.
> They do just fine. They don't tend to be obese,
> but they are fine. My girlfriend loves raw meat and
> eats it. [b]Raw fish is quite nice as well[/b].
>
> A seafood/shellfish and perhaps turtle mainstay diet
> makes sense for supporting brain growth. But most of
> this speculation about brain size and energy
> requirements just falls on its face when one looks at
> the facts. Truth is, humans can and do eat almost
> anything and survive well. And it doesn't harm
> their brains.
Fish in a vegan diet !
come on, learn first !
Um Flores people had fire and primitive wrists. That does at least suggest cooking might have been an LCA trait shared with them.
Reply | Report Abuse | Link to thisIs there any chance that hot springs were utilized for cooking in the past? Would it be possible that this predated the use of fire?
Reply | Report Abuse | Link to thisThis is fascinating work and reminds me of work done decades ago by Professor David Rindos, who was, very briefly, a colleague at Michigan State University. See Rindos, David.
Reply | Report Abuse | Link to thisTitle The origins of agriculture : an evolutionary perspective / David Rindos ; with foreword by Robert C. Dunnell. Publisher Orlando : Academic Press, 1984. See the MSU Library citation at http://magic.msu.edu/search?/aRindos%2C+David./arindos+david/-3%2C-1%2C0%2CB/frameset&FF=arindos+david&1%2C1%2C
This is crazy! The prime source of high energy food was most likely fish and other higly nutritious seafood along beaches. Hunting and gathering away from the most productive ecosystems in Africa would be senseless for an animal that had learned to dominant these areas (keep the predators at bay). For many reasons we, unlike chimps, gorillas and orangutans, today show features that indicate that we came down out of the trees and starting living on the beach where we got more food, learned how to swim and lost most of our fur. Like the vegans point out you can live on a raw-food vegan diet but you would have to spend a lot of time eating like chimps do. Eating seafood would require no cooking and would likely result in access to food with a higher energy to weight ration (lots of fat and protein). This is the amphibious-generalist hypothesis of Andrew Lewis.
Reply | Report Abuse | Link to thishttp://www.geocities.com/Athens/Acropolis/4314/intromhh.html
Since chimps cannot utilise fire, and likely the austrolapithecines couldn't either, there must have been another stimulus that enabled the initial brain growth to permit fire exploitation in the first place. After that, I can see how the caloric superfluity associated with cooking could keep the expansion going, and indirectly accelerate the process by providing further selection pressure (given the hazards of fire, and difficulties in starting and controlling it).
Reply | Report Abuse | Link to thisYou don't necessarily HAVE to cook...you can DRY food to preserve it for later use.
Reply | Report Abuse | Link to thisIt ALL boils down to a steady supply of high quality, high protein, food...right? Drying meat/fish is EASY to do and doesn't require much "smarts" to begin with. This supply of high quality food could have been the catalyst that started the "big brain" evolution.
Actual "cooking" could have come long after drying.
As for a vegan diet...I don't think it's possible without our modern society that allows fresh foods to be available all year long through global transportation.
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Reply | Report Abuse | Link to thishttp://www.culinaryschoolsprograms.com/
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I am wondering if when the stomachs started shrinking, if that fueled the evolutionary chain even faster. With a smaller stomach, you need less food, therefore your brain is allowed to do something other than hunt and forage. That is where the growth of the brain would have picked up the pace again.
Reply | Report Abuse | Link to thisI am wondering if when the stomachs started shrinking, if that fueled the evolutionary chain even faster. With a smaller stomach, you need less food, therefore your brain is allowed to do something other than hunt and forage. That is where the growth of the brain would have picked up the pace again.
Reply | Report Abuse | Link to thismy sceptical friend wants to know why her gut is getting bigger and her brain seems to be getting smaller as she ages
Reply | Report Abuse | Link to thisThe comments in supra boxes are twelve years old. Availability of information and thinking process in the society has changed a lot since then. I realize that the aborigines living in certain islands of Pacific and Indian ocean till few decades ago were not wearing clothes and were surviving largely on raw food whether fruits or flesh. I am sure this must have been the case with these aborigines for hundreds of centuries. Does this tell us that in these islands (which are totaly cut off from the rest of the world) the apes got evolved into humans or that the homo erectus existed in the same form since the begining. when I see the beautiful and colourful creation of NATURE, which the world is, I tend to feel more and more convinced that Homo sapience was created by the nature as a distinct specy of life awarded with brains as an inbuilt character/component from the begining and not thru a process the present day anthropologists are trying to discover. I wonder why people want to look differently.
Reply | Report Abuse | Link to thisI think no matter what the facts are, vegetarians and vegans will always be in denial. Maybe they have de-evolved.
Reply | Report Abuse | Link to thisThe theory about cooking is based on sound logic.
Reply | Report Abuse | Link to thisCooking unlocks more nutrients in food, so you ineffect need less food, spend less energy and thereforecan use brain activity for other pursuits. (over cooking however kills nutrients).
Vegan diets are a modern phenomenen and could not exist with moden farming and storage methods.
I really cannot understand why some of the vegan and vegetarian fraternity are in so much denial?
Other benefits of cooking would be to kill harmful bacteria and germs, and in some cases make the raw inedible edible.
Fish of course is also meat , as is chicken, and all the other forms of meat that North Americans and Australians, for some strange reason, often insist is not.
Reply | Report Abuse | Link to thisI disagree. Lieberman’s and Bramble’s hypothesis is far more convincing: Homo became hairless as Homo became the world’s best endurance runner because hairy runners can’t cool down efficiently (as I can testify from personal experience).
Reply | Report Abuse | Link to thisBabies and infants don’t wear clothing at the beach. True, in many cultures, many adults do, but take a look at any beach in France and you will see that most females are wearing next to nothing. The wearing of clothes on a hot summer’s day at the beach is much more likely to be the result of culturally transmitted values than an artefact of our evolutionary history.
It occurs to me that the first cooked food eaten by our ancestors was likely scavenged animals killed and partially cooked by grass fires. I suggest grass fires over forest fires due to the greater concentration of animals on the plains. In addition forest fires generate more heat for a longer time and the carcass is more likely to be reduced to little more than bone.
Reply | Report Abuse | Link to thisIn all the discussions on eating scavenged food only meat and fat are mentioned. Though difficult to determine I would suggest that the partially digested contents of ruminant stomachs are edible and were consumed. From speaking to the local west coast natives on bush survival they mentioned that an all meat diet can cause gut problems such as severe cramping. By mixing in some of the partially digested stomach contents these problems can be alleviated. They went on to say that in an emergency ruminant dung could be substituted. In addition to alleviating stomach problems some minerals and vitamins would be released by the digestive process and become available for our use.
While these discussions were referring to surviving emergency's I would suggest that they are also applicable to the day to day survival of our ancestors.
Interesting argument！
Reply | Report Abuse | Link to thisAnyhow,cooking is one of the results of human using tools and in turn,it helps enlarge human's brains.So maybe it does have some connection between cooking and brain,but who sets the change first?