A new study has found out why humans are smarter and have bigger brains than chimpanzees despite the fact we share 98 percent of our DNA.
Human brains undergo an explosion of white matter growth, or connections between brain cells, in the first two years of life that chimpanzee brains do not, leading to greater human intelligence.
Chet Sherwood, an evolutionary neuroscientist at George Washington University, tells Live Science:
“What’s really unique about us is that our brains experience rapid establishment of connectivity in the first two years of life. That probably helps to explain why those first few years of human life are so critical to set us on the course to language acquisition, cultural knowledge and all those things that make us human.”
Although past studies have shown that human brains undergo an expansion of connectivity, it wasn’t known if our closest relatives, the great apes, developed in the same way. In order to prove superior human intelligence, researchers needed to prove human brains were different than chimpanzee brains.
The researchers did live MRI brain scans of three baby chimps until they were 6 years old. Then, researchers compared the data to MRI scans of six macaques monkeys and 28 Japanese children.
According to Yahoo News, the researchers found that chimpanzee and human brain development “increase[d] in total cerebral volume during early infancy and the juvenile stage in chimpanzees and humans was approximately three times greater than that in macaques.” They also found human brains expanded more than chimpanzee brains especially in the connections between brain cells or white matter. Sherwood also told Yahoo News that although the findings were expected it was a unique finding because they were able to follow the same chimpanzees over time.
The results of the study were published in “The Proceedings of the Royal Society B” December 18, 21012.