Evolution in the News - February 2008
by Do-While Jones

Half-baked Evolution

Scientific American reports that cooking caused our chimplike ancestors’ brains to get smarter. If that isn’t a half-baked idea, we don’t know what is!

Just when we thought evolutionists could not come up with anything dumber, we read this article in last month’s Scientific American. Here is the title and subtitle.

Cooking Up Bigger Brains

Our hominid ancestors could never have eaten enough raw food to support our large, calorie-hungry brains, Richard Wrangham claims. The secret to our evolution, he says, is cooking 1

Here is Wrangham’s hypothesis. Try not to laugh.

“What would it take to convert a chimpanzeelike ancestor into a human?” Fire to cook food, he reasoned, which led to bigger bodies and brains. 2

Cooking could have made the fibrous fruits, along with the tubers and tough, raw meat that chimps also eat, much more easily digestible, he thought—they could be consumed quickly and digested with less energy. This innovation could have enabled our chimp­like ancestors’ gut size to shrink over evolutionary time; the energy that would have gone to support a larger gut might have instead sparked the evolution of our bigger-brained, larger-bodied, humanlike forebears. 3

This is not science. It is speculation.

The Scientific Approach

He believes that eating cooked food caused human ancestors to evolve bigger brains. OK. So far, so good. He has a hypothesis. There is nothing wrong with that. That’s how scientific inquiry begins. But he doesn’t know what to do with the hypothesis. The next step is to devise an experiment to test his hypothesis. He should acquire a number of laboratory animals (mice, rats, guinea pigs, or gerbils) and divide them into two groups. Feed one group raw food, and feed the other group cooked food. Then use some sort of intelligence test (run a maze, figure out how to push a button for a reward, etc.) to see if the group that eats cooked food is smarter (and grows bigger brains) than the group that eats raw food. That’s what a scientist does. He tests his hypothesis with an experiment.

The experiment can’t end there. In the immortal words of Charles Darwin,

Any variation which is not inherited is unimportant for us. 4

Even if eating cooked food does produce smarter, bigger brains in the individual that eats the cooked food, it only matters if that improvement is inherited by the offspring. Otherwise, evolution has to start over again with every generation. So, the scientist has to repeat the experiment with several generations, showing that the brain improvement is inherited, and is cumulative.

Why hasn’t Wrangham proved his hypothesis this way? You know the answer as well as we do. Feeding cooked food to an animal isn’t likely to make it any smarter. Even if it does, there is no reason to believe that eating cooked food will cause a mutation in the DNA making the offspring smarter. He could feed cooked food to countless generations of rats, and they would never get smart enough to cook the food themselves.

His Non-scientific Approach

“I tend to think about human evolution through the lens of chimps,” he remarks. “What would it take to convert a chimpanzeelike ancestor into a human?” Fire to cook food, he reasoned, which led to bigger bodies and brains.

And that is exactly what he found in Homo erectus, our ancestor that first appeared 1.6 million to 1.9 million years ago. H. erectus’s brain was 50 percent larger than that of its predecessor, H. habilis, and it experienced the biggest drop in tooth size in human evolution. “There’s no other time that satisfies expectations that we would have for changes in the body that would be accompanied by cooking,” Wrangham says. 5

Notice what he DIDN’T say. He didn’t say that scientists had previously found lots of evidence of the controlled use of fire at H. erectus sites, and no evidence of fire at H. habilis sites, which led him to his theory. The theory came first. Then he went looking for data to back up his theory.

Wrangham points to some data of early fires that may indicate that H. erectus did indeed tame fire. At Koobi Fora in Kenya, anthropologist Ralph Rowlett of the University of Missouri–Columbia has found evidence of scorched earth from 1.6 million years ago that contains a mixture of burned wood types, indicating purposely made fire and no signs of roots having burned underground (a tree struck by lightning would show only one wood type and burned roots). The discoveries are consistent with human-controlled fire. Rowlett plans next to study the starch granules found in the area to see if food could have been cooked there. 6

Still, most researchers state that unless evidence of controlled fire can be regularly confirmed at most H. erectus sites, they will remain skeptical of Wrangham’s theory. 7

Evolutionists sometimes criticize creationists for having a preconceived belief, and then looking for data to support that belief. This evolutionist is doing the same thing. Actually, there is nothing wrong with looking for evidence to support your previously held belief. But it is wrong to accept only the data that supports your theory and ignore all the data against it.

A Long Lunch Hour

Wrangham and his colleagues calculated that H. erectus (which was in H. sapiens’s size range) would have to eat roughly 12 pounds of raw plant food a day, or six pounds of raw plants plus raw meat, to get enough calories to survive. Studies on modern women show that those on a raw vegetarian diet often miss their menstrual periods because of lack of energy. Adding high-energy raw meat does not help much, either—Wrangham found data showing that even at chimps’ chewing rate, which can deliver them 400 food calories per hour, H. erectus would have needed to chew raw meat for 5.7 to 6.2 hours a day to fulfill its daily energy needs. When it was not gathering food, it would literally be chewing that food for the rest of the day. 8

If Homo erectus spent the whole day gathering and chewing food, he wouldn’t have time to commute to work, assemble data into an Excel spreadsheet, give a presentation to the boss, and commute home! Seriously, do animals have anything better to do than to spend all day every day looking for food and eating it?

I wrote to a friend (vegetarian from birth) who switched to a raw food diet more than a year ago. I asked him how much he eats, and how long it takes to eat it. Here’s what he wrote back:

Here is a summary of my menu:
Breakfast - 15 Minutes
16 oz fruit (fresh bananas, apples, oranges)
2 oz nuts
Lunch - 30 Minutes
16 oz lettuce, spinach, sprouts
2 oz tomato
2 oz avocado
4 oz olives
2 oz nuts
Dinner - 15 Minutes
16 oz fruit
2 oz nuts

That adds up to nearly 4 pounds, and one hour of eating time. This gives him a big enough brain, and plenty of time to drive to a secret location 30 miles away out in the desert, take weapons data, put it into an Excel spreadsheet, present it to his boss, and drive home.

Tabloid Science

In fairness, Scientific American acknowledges that most scientists think this idea is absolutely nuts. The theory has no merit whatsoever. But why would they print the story if they didn’t think it was credible? Did they print it just to sell magazines?

It is intentionally misleading. There are people who don’t read much more than the headline. If one just reads the headline and subheading, one could easily get the impression that it has been proved that cooking caused human evolution.

If you have ever read a supermarket tabloid (come on, admit it, even if you didn’t buy it), you know how misleading their headlines are. But sensational headlines sell tabloids. Scientific American, Discover, and National Geographic, are facing the same economic pressures that other print magazines and newspapers are. They have to do something to increase circulation, so they print bogus stories like these at the cost of credibility.

Unfortunately, many readers will confuse this tabloid science with real science. Cooking food does not make people smarter, and it certainly does not change their DNA so that their children will have bigger brains.

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Footnotes:

1 Gorman, Scientific American, January 2008, “Cooking Up Bigger Brains”, page 102
2 ibid.
3 ibid.
4 Darwin, 1859, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, Chapter 1
5 Gorman, Scientific American, January 2008, “Cooking Up Bigger Brains”, page 102
6 ibid.
7 ibid.
8 ibid.