Washington, August 15 : A new research has suggested that cooking meat may have made our ancestors smarter.
According to a report in Live Science, the research indicates that the brain's roaring metabolism, possibly stimulated by early man's invention of cooking, may be the main factor behind our most critical cognitive leap.
About 2 million years ago, the human brain rapidly increased its mass until it was double the size of other primate brains.
"This happened because we started to eat better food, like eating more meat," said researcher Philipp Khaitovich of the Partner Institute for Computational Biology in Shanghai. "But the increase in size did not make humans as smart as they are today," he added.
For a long time, humans did little but make the same very boring stone tools for almost 2 million years, according to Khaitovich.
Then, only about 150,000 years ago, a different type of spurt happened - our big brains suddenly got smart.
Humans started innovating by trying different materials, such as bone, and invented many new tools, including needles for beadwork.
Responding to, presumably, the first abstract thoughts, humans started creating art and maybe even religion.
To understand what caused the cognitive spurt, Khaitovich and colleagues examined chemical brain processes known to have changed in the past 200,000 years.
Comparing apes and humans, they found the most robust differences were for processes involved in energy metabolism.
According to Khaitovich, the finding suggests that increased access to calories spurred our cognitive advances, adding that definitive claims of causation are premature.
In most animals, the gut needs a lot of energy to grind out nourishment from food sources. But cooking, by breaking down fibers and making nutrients more readily available, is a way of processing food outside the body.
Eating (mostly) cooked meals would have lessened the energy needs of our digestion systems, Khaitovich explained, thereby freeing up calories for our brains.
Instead of growing even larger (which would have made birth even more problematic), the human brain most likely used the additional calories to grease the wheels of its internal functioning, thus becoming smarter in the process.