Led by University of Adelaide Professor Roger Seymour, the group examined several different Hominin fossil skulls ranging from the 3 million-year-old Australopithecus to those of modern humans. However, they did not focus on the size of the head. Instead, the scientists carefully measured and documented the diameter of the holes at the base of each skull that accommodate the blood-delivering arteries.
The researchers discovered that the size of the holes increased drastically over time, indicating that additional blood was being pumped into the brain. According to the team’s calculations, over the course of human evolution, the amount of blood supply increased by 600%, while the size of the human brain grew by only 350%.