Traditionally, our “big brain” was supposed to be what distinguished our species from other animals. Our ability to think and innovate enabled us to create the first artwork, invent the wheel, and even land on the moon.
Certainly, when compared to other creatures of equal size, our brains are massive. The human brain has roughly doubled in size in the six million years since our species’ last common ancestor with chimps. However, research reveal that the trend toward larger brains has reversed in Homo sapiens. The average brain size in our species has decreased over time.
For example, in a recent 2023 study, Ian Tattersall, a paleoanthropologist and retired curator at the American Museum of Natural History in New York City, traced the braincase volumes of ancient hominins across time. He began with the earliest known animals and concluded with modern humans.