Rebecca Moragne, TuftScope Research Highlights Editor
The “[human brain] is remarkable, but it is not exceptional,” states to Suzana Herculano-Houzel, Vanderbilt University neuroscientist. A new study led by Herculano-Houzel reveals that the human brain is more similar to primate brains than originally proposed. A larger prefrontal brain region thought to differentiate a human’s brain from a primate’s. The prefrontal region of the brain controls decision-making, planning, and thinking. However, the differentiating factor is total amount of neurons. Both a human and primate’s prefrontal region are made up of the same proportion of neurons and fill the same relative volume. The human brain is comprised of more neurons than the gorilla and orangutan, whose bodies are larger than human’s. In basic terms, the human brain is a primate brain, but specifically the largest one.
How did the human brain grow so big? Cooking. Cooking allows a consumer to obtain more calories from food. Without cooking, primates bear an energetic barrier that limits the size of their brains. An energetic barrier directly affects the size of a brain because a brain uses 35% of the body’s energy daily. Herculano-Hauzel describes cooking’s importance through a carrot: “Take a single carrot. If you eat it raw, it will take 10 or 15 minutes of vigorous chewing and your digestive system will only capture about one third of the calories. But, if you cut the carrot up and cook it for a few minutes, if takes only a few minutes to consume and your body gets 100 percent of the calories.” 2.5 million years ago the first stone tools were developed. These allowed for food to be cut up and mashed. During this time human brains were the same size as gorillas’ but 0.7 million years later they started to grow. And by 1.5 million years ago the size of the human brain had tripled. A human brain is both incredibly unique and incredibly similar to a primate brain. But the reason for size difference between the brains is quite simple.
Vanderbilt University. (2016, August 10). Total number of neurons -- not enlarged prefrontal region -- hallmark of human brain. ScienceDaily. Retrieved September 25, 2016 from www.sciencedaily.com/releases/2016/08/160810143716.htm