There once was a common belief that suggested ancient humans' brains increased in size due to meat consumption, but a new theory seems to debunk that idea.
There is evidence that Homo erectus, the ancestor of Homo sapiens, had larger brains than any of its predecessors. The increase in the brains of our ancestors was thought to be due to meat consumption and this separates humans from other primates.
Our early ancestors began consuming meat between 2 million and 3 million years ago and according to a popular theory, having a diet that heavily relied on meat allowed Homo erectus to invest in brainpower. But the exact role of meat consumption played in early human evolution is challenged by a new study published in the journal Proceedings of the National Academy of Sciences.
“It’s clear that eating meat has been important for many groups of humans throughout much of human history and prehistory,” said lead author W. Andrew Barr, a paleoanthropologist who studies the environment of early human evolution at George Washington University.
The research team included Andrew Barr, Briana Pobiner, a zooarchaeologist at the Smithsonian’s Museum of Natural History, John Rowan, an assistant professor of anthropology at the University of Albany, Andrew Du, an assistant professor of anthropology and geography at Colorado State University, and J. Tyler Faith, an associate professor of anthropology at the University of Utah.
But brain size is not directly linked to meat consumption across carnivores. For example, the brain size of baboons tends to increase if they live in larger social groups. The other possibility that made a larger brain possible for Homo erectus is cooking, hence cooked meals are usually more nutritious than a raw diet.
Barr and his colleagues examined human activity dating between 2.6 million and 1.2 million years ago in 59 sites in eastern Africa. “We used the number of paleontological sites and the number of species preserved at those sites as a barometer for how much fossil-preservation potential there is in a given time period, and then we used that background level of sampling to contextualize the amount of cut-mark evidence preserved in the same period,” he explained.
The researchers found that, when accounting for variation in sampling effort over time, there is no sustained increase in the relative amount of evidence for carnivory after the appearance of Homo erectus.
Pobiner said, "This study changes our understanding of what the zooarchaeological record tells us about the earliest prehistoric meat-eating. It also shows how important it is that we continue to ask big questions about our evolution, while we also continue to uncover and analyze new evidence about our past."
The main reason for enlarged brains still seems to be blurry for humans but at least we know that thicker cortices make us smarter, or else sperm whales with brains weighing up to 20 lbs (9 kg) or leeches with their 32 brains would be the smartest animals on the planet. But at least we know for sure that humans use their brains way more than 10 percent, as another myth suggests.