In a recent study pertaining to human evolution, Harvard evolutionary anthropologists Daniel Lieberman and Katherine Zink demonstrated how hominins’ ability to prepare a rubbery carcass for consumption led to man’s ultimate ability to verbally communicate.

The prevalent hypothesis is due to greatly decreased chewing time, human jaw structure evolved into an adaptation fit for higher-level survival functions, such as speech. When speaking to Science, Lieberman compared hominin’s plight of consuming unaltered raw meat to that of masticating upon the nearly inconsumable muscle of goat.

“Eating raw goat is not pleasant,” says Lieberman, who tried out the methods himself. “You chew and you chew and you chew and you chew and nothing happens.” Human teeth simply can’t break up the flesh into smaller pieces we can swallow. “It’s almost like chewing gum,” Zink says. Chimps’ teeth are similarly bad at chewing meat. For our early ancestors, with their chimplike teeth and mouths, eating meat was probably a similarly time- and energy-consuming ordeal.”

[Photo by Kevork Djansezian/Getty Images]

Fossil remains demonstrate stark similarities in both mandible and molar-size between hominin and chimpanzees. Whereas chimpanzees still spend upwards of five-to-eleven hours per day simply chewing their food, it was a boon for human evolution when our early ancestors began curtailing this tedious process by mashing and slicing meals prior to consumption.

In addition to streamlining this evolutionary process that led to smaller jaws and teeth, hominin’s culinary ingenuity has been linked to development in modern-man’s brain shape and size, as well as body-heat regulation.

These overall findings comprise a new theory that would counteract preceding data gathered in the area, suggesting that the advent of cooking over fire was largely responsible for early man’s decrease in jaw and tooth size.

ALL THAT’S FIT TO EAT

The Liberman/Zink experiment proposes rudimentary tool uses for food processing, along with further advancements in food gathering and preparation, began man’s path to physiological speech capabilities. The crux of the Liberman/Zink trails, though, is tool use was the all-important precursor to “the cooking theories” principle tenets. In essence, if there were no tool-use, ancient man may never have begun using fire as a means for food consumption.

Richard Wranghman, a proponent for the cooking theory had this to say to Science.com concerning his views pertaining to the Liberman/Zink trails.

“I cannot see how the diets that [Zink and Lieberman] are proposing can explain the combination of smaller chewing [features] and, very importantly, the smaller gut” seen in early members of Homo starting about 1.9 million years ago. For me the big problem is you need a big gut to be able to ferment the raw plant foods that these animals would have been eating.”

[Photo by Tim Boyle/Getty Images]

As Wranghman’s stance that the ability to gather — and effectively cook — calorie-dense meat provided early man with the nutrients to further develop higher-cognitive functions, while spurring an evolutionary shift in mandible and tooth size is undebatable, what is debatable is the means by which our ancestors were led to this point.

As scientists in the field of anthropological study gather and interpret greater amounts of data, more insight into the origins of man becomes clearer. The recent experiment conducted by the two Harvard scholars has added another important piece to a much larger puzzle pertaining to this matter.

The casual efficacy of the logic stating that less time spent chewing equates to more time spent developing higher-reasoning capabilities – such as roasting meat, which ultimately led to speech – is an exciting find for the scientific community.

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