There are many other features in the head that help us become exceptional long-distance walkers and runners. I became obsessed with the idea that humans evolved to run long distances, evolved to walk long distances, basically evolved to use our bodies as athletes. These traces are there in our heads along with those brains.
DANIEL LIEBERMAN is Professor of Human Evolutionary Biology at Harvard University. His research combines experimental biology and paleontology to ask why and how the human body looks and functions the way it does. He is especially interested in the origin of bipedal walking, the biology and evolution of endurance running, and the evolution of the human head. He also loves to run. Daniel Lieberman's Edge Bio Page