The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say. Science Photo Library/Corbis hide caption

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"Flavor is the most important ingredient at the core of what we are. It created us," John McQuaid writes in his book Tasty: The Art and Science of What We Eat. Getty Images hide caption

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Actors Stan Laurel and Edna Marlon play at socializing around the campfire. It turns out that early man's brain developed in part thanks to cooking. Hulton Archive/Getty hide caption

itoggle caption Hulton Archive/Getty