Researchers suggest eating cooked food led to larger human brains

October 23, 2012 by Bob Yirka report
brain
MRI brain scan

(Medical Xpress)—Brazilian researchers Karina Fonseca-Azevedo and Suzana Herculano-Houzel suggest humans evolved bigger brains because they learned to cook their food. In a paper published in the Proceedings of the National Academy of Sciences, the two outline research they've conducted that involved counting the number of neurons in the brains of various primates, the results of which showed that the only way early humans could have evolved bigger brains was to find a way to get more energy from the food they ate, i.e. cooking it.

Cooking food causes it to break down in ways similar to digestion. Thus, animals that eat cooked food don't have to expend as much energy digesting it as do those that eat their meals raw. Because of this, the researchers in this new study proposed that learning to cook food allowed more time to engage in other pursuits that eventually led to the development of larger brains. To prove their idea sound, they compared the amount and types of food various primates consume and compared it with the amount of energy necessary to fuel their brains which they calculated by counting .

They began by counting the neurons in the brains of several species of modern primates and then calculated how much time each would have to invest in eating, based on their diet, to maintain their brain sizes. They found that humans would need to eat almost nine and a half hours every day if they didn't cook their food, that gorillas use on average 8.8 hours a day eating, 7.8 and chimps 7.3. They also found that the size of an animal's brain is directly linked to the amount of neurons it has and that the number of neurons it has is directly proportional to the number of calories needed to keep the brain fed.

Applying their results to early humans: Paranthropus boise, and afarensis, the researchers calculated that each would have had to spend approximately seven hours a day eating just to maintain their brain size. They suggest that instead, early man learned to cook, which resulted in far less time devoted to foraging and eating, and more to socializing and engaging in other activities that over time led to larger brain sizes, fueled by cooked food.

Explore further: Big brains evolved due to capacity for exercise

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loneislander
5 / 5 (2) Oct 23, 2012
Not to rain on anyone's research but I heard this idea at least 25 years ago. Great to explore it from anew, regardless.
plastikman
2.8 / 5 (4) Oct 23, 2012
I would think you'd already have to be pretty smart to a. start and maintain a fire and b. figure out how to cook your food!
Caliban
3 / 5 (2) Oct 24, 2012
Probably not such a leap from finding, a dead, partially-roasted game animal in the fringe of a still-smoldering burned over area after a wildfire, to flopping some of the less well-cooked(to try and reproduce the roasted taste) carcass over some still burning brush or wood, to skewering the meat to better control cooking, to transporting some burning material to a sheltered place, like a cave, and tending the fire to keep it going.

A much more difficult leap was likely to have been learning how to start a fire independent of an available living one. Probably by chance and observation, followed by diligent trial and error. And likely to have occurred long after firetending was learned.

thingumbobesquire
1 / 5 (1) Oct 24, 2012
This coheres with the fact that humans uniquely as a species use fire which fundamentally separates us from all other biological life forms. From that point we have developed ever more energy dense forms of fuel leading up to the research in nuclear fusion today. This boundary of human technological progress is what Verdnadsky called the Noosphere.

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