Saturday, June 13, 2009

Mr. Wrangham’s Excellent Conjecture

Richard Wrangham is about to publish a book, Catching Fire: How Cooking Made Us Human, where (according to New York Times author Claudia Dreifus) he suggests that cooking was an essential ingredient in our rise above our fellow primates, largely by reducing the amount of time spend chewing our food up. He compared our primal diet to that of chimps which, he says in an interview with Ms Dreifus, they’d have to “masticate for a full hour.” By cooking one could cram the same food down ones gullet in a few minutes, leaving one, presumably, more time to work on ones sonnets and Pythagorean theorems.


I haven’t read Wrangham’s manuscript, but I have read the NY Times interview plus another article on his proposal and am prepared to make a few observations.

The first of which being it is an excellent observation and undoubtedly one with a lot of merit. Unquestionably, cooking took hold for some reason. Whether or not cooked food is “more nutritious” and “healthier,” than uncooked food is certainly open to debate and shouldn’t be accepted prima facie (although cooking definitely makes some foods palatable, which could otherwise be deadly), but that cooking makes food quicker to eat is undoubtedly true, although that may not have played as great a role in its adoption as flavor. If Wrangham displays any major fault with his theory, it’s that he’s too much in love with it, a common problem with theories; I suffer it myself.

Another fault is comparing us to chimps too keenly. Unquestionably, we’re closely related to them and their cousins the bonobos, but we’re likewise a lot different. No one would confuse the two of us walking down the street. And while we may share a distant ancestor, we long ago took different paths; occupied different parts of the forest; and, evidently, ate a different diet; something Wrangham has yet to fully grasp, even after trying to mimic the chimp diet when he was living in Tanzania in 1972. It’s true, we’re both omnivores, but that doesn’t mean we eat the same things; and trying to figure out what a chimp eats won’t necessarily lead you to what proto-people ate two or three million years ago. Especially if you don’t know where those proto-people lived, an issue about which Wrangham is confused. (We won’t get into Wrangham’s being primarily a vegetarian, which casts serious doubt on his understanding of both nutrition and evolution. I should mention here that I had a wife once who tried to emulate the diet of her goats, under reasoning not too different from Wrangham’s, but was dissuaded after the first mouthful of barbed grass heads stuck in her throat for hours.)

Wrangham bases much of his argument on assumptions about human fire use from 1.8 million years ago, a somewhat earlier date for fire use than is generally agreed upon, but not so early as to be improbable. What becomes questionable is to what uses fire was put at that early time and how often was it available. The only sources I’ve found estimating when people were first capable of “making” fire pegs that date between 9,000 and 15,000 years ago, which seems impossibly recent to me. It’s hard for me to believe lightning could be a reliable source of fire, particularly for people traversing the northern reaches at the edge of glaciers, but it’s certainly likely that people were able to control fire long before they could create it. Still, it’s hard to imagine that accidental fire would ever be common or ubiquitous. One can only imagine that for eons people clustered around fires when they had one, but that for most people most of the time there was no artificial warmth; and when someone decided to try cooking something other than a hunk of meat is not determined. In any event, people were upright creatures millions of years before they captured fire, and they were, apparently, already on a superior road to the chimps by the time they stood up for good, long before they started cooking anything. Cooking was a great technological leap and a great time-saver, but it probably didn’t affect our basic nutritional intake, at least at first. Certainly, as some products lend themselves more conveniently to cooking, they tend to become emphasized, but I can only presume that cooking didn’t initially affect food choice. The bottom line, though, is that we have and had our own dietary preferences which are distinguished from what other apes eat and most likely always have been. It’s likely that those early dietary differentials are part of what propelled us on the path we found ourselves; not to mention that those diety preferences probably caused us to becaome upright, as well.

Wrangham drops other bon mots into his conversation which are clearly either inaccurate or unknown. When he states that “the austrolopithicines, the predecessors of our prehuman ancestors, lived in savannahs with dry uplands,” he’s making both errors and assumptions. When the austrolopithicines first descended from the branches, there were no savannas where they were. True, they showed up by the time fire was captured, but they certainly weren’t where any prehumans lived. The austrolopithicines weren’t able to change their habitat, just because their world was drying out around them. Fortunately for them, they lived in a micro-environment along river banks and around marshes and swamps that may have been reduced in size, but never disappeared. When the savannas appeared they could forage, scavenge, and hunt them without actually living in them; provided, of course, that they’d developed weapons and a way to carry water.

Wrangham, likewise, makes several assumptions about how having fires changed our socialization, such as fires providing a stabilizing hearth around which people would then cluster. “This was clearly a very different system from wandering around chimpanzee-style, sleeping wherever you wanted, always able to leave a group if there was any kind of social conflict,” he claims; ignoring that most animals, I’ll bet chimps included, have regular bedding spots (not to mention birthing spots) that aren’t chosen so devil-may-carefully as Wrangham would suggest. Offhand, despite a myth of wandering animals and people, everything has a home territory, every bird has its branch. Even albatrosses.

And while it may be a minor point, there’s no guarantee that austrolopithicines were our ancestors any more than the species h. habilis was, which he also claims as a “distant ancestor.” If an ancestor is a person in ones direct line, then there is no assurance that either austrolopithicines or habilis were our ancestors. We may all have shared another as yet undiscovered ancestor. Someday we might have tests that can determine the relationship of those old fossils to ourselves, but in the meantime we’re going to have to go on the assumption that those old species were relatives, but not necessarily ancestors. We can safely assume that the majority of fossil primate species, bipedal ones included, have yet to be discovered and may never be. Just because a species that shares many of our traits was common at an earlier time doesn’t mean that it is in our direct line.

One also has to wonder about Wrangham’s general life experiences when he makes a statement like, “They [h. habilis] certainly made hammers from stones, which they may have used to tenderize [meat]. We know that sparks fly when you hammer stone. It’s reasonable to imagine that our ancestors ate food warmed by the fires they ignited when they prepared their meat.”

No it’s not. It’s not reasonable at all. It’s a prime example of being in love with ones own theory; once you’re in love, anything is possible. Even if it’s not. Nobody whacking away at a wet piece of meat with a rock is going to send off sparks that are going to catch that meat on fire. Or anything else laying nearby, either. Ain’t gonna happen. If it happened once in the entire history of humanity, I’d be amazed, but to depend on it as a way to get ones cooking fire going? The danger of stretching ones argument like that is that it casts doubt on the rest of ones propositions.

Such as trying to emulate chimps’ eating patterns. He wanted to eat just like a chimp but “in the end… never did the full experiment.” He did allow, though, that “there were times when I went off without eating in the mornings and tried living off whatever I found. It left me extremely hungry.” He relays this, as if it was a valid contribution to the discussion; that it was a valid experiment from which he got a significant result: he was hungry. Aside from the aforementioned problem that we don’t share a diet with chimps, here was an untrained, naive city boy trying to live off what he could find to eat, despite not knowing beans about what’s edible or not in the landscape. And then he has the balls to imply that his hunger was akin to what all “prehumans” would have experienced.

Not likely. And remind me not to go hunting with this guy.

A couple other suppositions surrounding fire test the credulity of the most humble among us:

One was that early cooks would place carcasses in front of advancing wildfires in order to have them cooked as the fire passed over; which surely explains the high hazardous duty pay that habilis cooks earned. Not to mention an attrition rate higher than kamikaze pilots. This supposition, even though burned bones can be analyzed to see whether it was a cooking or a wildfire that charred them, as cooking fires reach much higher temperatures than wildfires. In other words, not only would such a method of cooking be absurdly dangerous, it wouldn’t provide a superior, or necessarily even adequate, result. Trust me, our ancestors survived to become us because they were clever, not foolhardy.

Another amazing suggestion is that people lost their fur/hair in front of the fire, the hair being no longer necessary to keep one warm. It immediately makes me picture the cowboys coming in from the range after riding herd, gathering round the camp fire, taking off their clothes… Sure, we’ve all seen Brokeback Mountain. We know all about campfires and long, lonely nights. Heck, every campfire I’ve ever been at, everyone has taken off their clothes. Your fires, too, I imagine. All that notwithstanding, wouldn’t we expect people who’d lost their hair from sitting in front of a fire to have gotten bald chests and hairy backs? Why hair on the tops of ones heads, for God’s sake? How about to keep from getting sunburned?

That’s what’s meant about the dangers of falling in love with ones own theory. The seduction to explain everything is too great.

It’s too bad, because the origins of cooking are obscure, yet obviously crucial to human development. The relationship between cooking and farming has yet to be explored in any detail. Did we cook anything other than meat prior to the adoption of farming? Was cooking a catalyst for farming? It’s an intriguing question which Wrangham is right to approach. Hopefully, the next person to look at the subject will be more grounded.

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