When Charles Darwin proposed his theory of evolution in 1859, he sparked a long-standing debate over the true origin of mankind.

But while the debate rages on, a new question has shifted some attention to a different issue. Instead of realizing where human beings initially came from, many people strive to understand what caused human evolution in the first place.

University anthropology professor Greg Laden said the driving force behind certain primates’ evolution into hominids and eventually into humans might have been their desire for cooked food.

“Cooking is a human universal,” wrote Laden and four of his
colleagues from Harvard University, who first published their hypothesis in a paper presented in the December 1999 issue of Current Anthropology.

Every culture on the planet incorporates the collection, preparation and consumption of food into their lifestyle, the paper said. At least some portion of nearly every human’s diet involves cooked food.

Harvard anthropology professor Richard W. Wrangham, the paper’s co-author, said he believes it’s one of the primary ways humans differentiate themselves from all other animals.

“We distinguish ourselves from the rest of the world because they eat raw stuff and we eat cooked stuff,” Wrangham said in an interview conducted by the Edge Foundation in February.

“Cooking enormously increases the quality of the food we eat, and it enormously increases the range of food items that we can eat,” Wrangham said. In addition, cooking provides improved nutritional benefits and allows for easier digestion.

As a result, the physical makeup of hominids would have changed dramatically.

According to the hypothesis, teeth became smaller, since less chewing was necessary; the ribcage and gut got smaller with better digestion; and more nutritional calories were absorbed from each meal, meaning overall body size is expected to increase.

Laden notes that all these changes occur at a time when australopithecines, hominid creatures, evolved into Homo erectus, the immediate predecessors to modern humans, approximately 1.9 million years ago. He and Wrangham suggest this was when the first acts of cooking took place.

Traditionally, Darwin and others have attributed the distinct changes between hominid species, and in particular Homo erectus, to advancements in hunting and other characteristics of predatory behavior.

Dr. C. Loring Brace, University of Michigan anthropology professor, said he disagrees with Laden and Wrangham’s hypothesis.

“I look upon their gambit as belonging more to the realm of anthropological folklore than to that of science,” says Brace, who questions the evidence of controlled fire that far back in the fossil record.

Laden and Wrangham admit a lack of empirical evidence is a weakness in their hypothesis, but said they still believe in its validity.

“Our hypothesis has not been fully tested, but it is consistent with various lines of evidence, accounts for many of the important changes related to human origins and suggests new hypotheses to be tested through the fossil and archaeological record,” they wrote. “We present it, therefore, with the aim of stimulating new thinking.”

In that respect, Laden said, he considers the theory a success.

Commentary and criticism of the cooking hypothesis has brought new ideas into the anthropological forum, as well as increased attention to less popular theories, Laden said.

“It’s always been important,” Laden said of the debate over when controlled fire started, “but now (since the introduction of the cooking hypothesis) it’s even more important.”

“One of the ways that you measure the success of a paper is the extent to which it’s been cited,” he said. “And this one’s been cited more than average.”

Laden and Wrangham collaborated more recently on a research paper regarding the availability of roots as a major food source for ancestral hominids, which they said might have led to the development of bipedalism, or walking on two limbs.

The paper is in the final stages of development and is awaiting publication.

Brett Angel welcomes comments at
[email protected]