Cooking, and How It Slew the Beast Within

Joined Jul 24, 2001
I make the exception to post the whole article because NYT articles expire after some days and this is a very interesting one.

Thanks Alexia.

Cooking, and How It Slew the Beast Within

Among virtually every culture on earth, anything worth doing is best done over dinner. Bring out a nicely braised roast, a hot loaf of bread and a slice of, oh, lemon chess pie, and rifts can be healed, pacts sealed, loves revealed. Even the condemned do not want to leave this world without one really divine last supper

In the view of Dr. Richard W. Wrangham, a professor of anthropology at Harvard, the preparing, cooking and sociable eating of food are so central to the human experience that the culinary arts may well be what made us human in the first place.

Dr. Wrangham, who is renowned for his studies of chimpanzees, and of male aggression generally, proposes that the use of fire to cook food could date back almost 2 million years, a good 1.5 million years before the timing traditionally accorded it. He also suggests that the capacity to cook food could explain a wide array of hominid features, including a large brain, small teeth, a relative modesty of size difference, or sexual dimorphism, between men and women, and a tendency to pair up and put up with each other far longer than most primates do.

The theory has sparked a kind of pun-happy food fight among anthropologists, with some deriding it as "half-cooked" and causing "a good case of indigestion." But others toast its boldness.

"I feel a real harmony with a lot of his argument," said Dr. Kristin Hawkes, an anthropologist at the University of Utah. "It's so nice to have a set of alternative ideas to the conventional wisdom."

Dr. James F. O'Connell, another anthropologist at the University of Utah said, "The ability to cook food opened a very large niche for people, allowing them to eat foods they couldn't eat before, and to be in places they couldn't exploit before."

But Dr. C. Loring Brace, an anthropologist at the University of Michigan, argued that there was no good evidence that cooking was older than a quarter of a million years, and that many of the changes in the hominid line that Dr. Wrangham attributes to the discovery of cooking are much better explained by improvements in hunting technology. Dr. Wrangham "didn't check with enough of the right people before putting this idea into print," Dr. Brace said.

Dr. Wrangham initially presented the theory in the December 1999 issue of Current Anthropology, in a paper written with Dr. James Holland Jones, Dr. David Pilbeam and Dr. NancyLou Conklin-Brittain of Harvard and Dr. Greg Laden of the University of Minnesota. Dr. Wrangham has continued to elaborate on the thesis, most recently as a chapter in a newly published book, "Tree of Origin: What Primate Behavior Can Tell Us About Human Social Evolution," and online, in an extended interview on The Edge, an intellectual "salon" for scientists and their devotees.

While Dr. Wrangham admits that there is no "smoking gun" among the scant remains of humanity's ancient forebears — nothing akin to the evidence found in comparatively recent archaeological sites of repeatedly used hearthplaces, with their charred blocks and roasted animal bones. He points out, however, that most campfires set by traditional hunter-gatherers are small and fleeting affairs, which would not be expected to leave a strong signature over a million years and counting.

More to the point, he argues that many experts have failed to appreciate that the most salient dietary difference between humans and other species: they go for raw; we like it hot. "There's no record anywhere of any people who have lived without cooking," he said. Indeed, it was while he was staring at a campfire and imagining how hard life would be without fire that Dr. Wrangham came up with the first glimmers of the cooking hypothesis.

"I am an ecologist, and I think about how animals get their food, and what impact that has on their lives," he said. "I also know that primates are hungry all the time, and always desperate for a better meal."

What a revolution it must have been, he realized, that primal wielding of the saucepan. Not only does cooking make food delicious, it also makes it safer and more digestible, the better to extract the maximum number of calories from any given meal. Cooking bursts open the cells of foods and releases their nutritious innards; it breaks down long, tough chains of proteins and carbohydrates into simpler and more digestible sugars and peptides; and it detoxifies many of the defensive and potentially sickening compounds in plants, as well as killing many dangerous meat-borne microbes.

Surveying the literature, Dr. Wrangham and his colleagues determined that of the 48 types of roots, tubers and other potatolike plant foods eaten by humanity's foraging African forebears, 21 require cooking to be comestible. Other experts have calculated that when starchy foods like soybeans, potatoes and cassavas are cooked, they offer 75 to 100 percent more digestible calories than they do when eaten raw.

The nutritional benefits of cooking, they hypothesized, must have left extraordinary marks on hominid anatomy. Teeth would no longer have needed to chew their food so vigorously, and so would have gotten smaller, and the jaw itself probably followed. The gut and rib cage would also have downsized. "We don't need large fermentation chambers to break down long-chain carbohydrates," Dr. Wrangham said. "Cooking helps predigest our food."

By contrast, with all the extra calories that could be wrested from a meal, brain and overall body size would be expected to increase.

Yet when the researchers looked at what was happening to human anatomy at the time commonly proposed as the dawn of fine dining, 300,000 or so years ago, there was no evidence for changes like these.

To find the drastic bodily transformations that they thought must have resulted from a steep improvement in nutrition, the researchers had to go back 1.9 million years, when humanity's ancestors shifted from being small-brained, jut-jawed australopithecines to being cortically enhanced, small-faced and modestly dentitioned Homo erectus, the immediate predecessors to modern humans.That evolutionary leap, from australopithecine to Homo, was so extraordinary that it demands explanation, Dr. Wrangham said, and the party line, that it resulted from hominids' learning to hunt big game, doesn't work.

For one thing, there is evidence that australopithecines had been hunting large mammals for at least 600,000 years before the evolution of Homo erectus — why such a long delay? For another, if meat spelled the difference, why did the teeth of Homo erectus get so small and round? Carnivores generally have large, pointy teeth. Homo teeth are rather like big baby teeth, he said, designed to eat softened food

The researchers observed yet another significant change that occurred with the onset of H. erectus: the male is a tiny bit bigger than the australopithecine male, but the Homo erectus woman is full 60 percent taller and heavier than her female predecessor, an impressive discrepancy equivalent to the difference between a modern 10-year-old girl and a woman. So whatever happened at the evolutionary dividing line, females apparently reaped the greatest benefits: they were eating enough to get bigger, and among females, bigger generally means more fecund.

As a result of the asymmetrical expansion of females, the sexual dimorphism in the Homo line is much smaller than it was among our australopithecine ancestors. And that, Dr. Wrangham said, suggests the males were no longer under selective pressure to get bigger themselves. Because it is generally competition with other males that drives the need for male bulk, the transition to the Homo era must have brought with it the origins of the distinctly human pair bond. Males were no longer required to spend so much time fighting for females because something roughly and imperfectly approaching monogamy had entered into the mathematics of human mating.

If cooking seriously changed hominid proportions, might it have had a similarly radical impact on human behavior? Dr. Wrangham proposes that the need for people to gather food and bring it en masse to a kitchen-equivalent meant that thieves and cheats would have a comparatively richer opportunity to steal food. Males and females would have benefited from pairing up and defending their stocks together. Thus was born the hearth, the home, the nuclear family and the romantic, overpriced candlelit dinner.

As much as Dr. Wrangham admits that the evidence for ancient cooking is weak, it is not, he said, nonexistent. In some African sites, he said, anthropologists have found reddened patches of dirt dating back 1.6 million years that could be evidence of cooking fires.

Dr. Brace and other critics have dismissed these discoveries as red herrings. Some are probably not fire ash at all, Dr. Brace said, but traces of the metal manganese that have been misinterpreted for years. Other patches may indeed be the signature of antediluvian fires — set by lightning, not enterprising chefs. "Where the evidence of fire does occur, it indicates fires of huge temperatures, hundreds of degrees," he said. "These are not anthropogenic barbecues."

Dr. O'Connell of the University of Utah suggested that new studies now under way might resolve the question of how these fires began. The reddened patches are being scrutinized for their composition of so-called phytoliths, hard little silica particles found in plants, including wood products. If the phytolith signature in a given area proves to be the remnants of one type of plant, that would suggest the natural burning of a large tree, or a stand of bushes. If the signature is more diverse, it may be the result of various types of firewood being brought to the spot for a campfire.

Other researchers who doubt that early Homo erectus knew how to cook food nonetheless agree with Dr. Wrangham that the role of cooking in human affairs has been woefully neglected — perhaps because the men who historically have been anthropology's grand hypothesizers are unaccustomed to wearing an apron.

Dr. Sonia Ragir, an anthropologist at the College of Staten Island of the City University of New York, has argued that cooking did benefit women preferentially, though at a much later time in evolution than Dr. Wrangham believes. As she sees it, the increase in stature seen among archaic females occurred slowly, and picked up steam only toward the end of Homo erectus's reign, just about when cooking is thought to have taken hold.

Women, Dr. Ragir said, being burdened with children and thus less mobile than men, were the likely keepers of the tribal flame. As they tended the fire and cooked the meat and tubers, they could sample the food with impunity. "Women would have had access to food before it was distributed to everybody in the group," she said. "I call it the nibbling theory of human evolution."

And once snacking had been invented, all the glories of human civilization were bound to follow.

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