In the last 160,000 years, the shape of the human brain has barely changed
The changes to the human brain are due to the the face and not the brain itself
Although the cranium, or brain case, of early modern humans dating back 200,000 years isn't much larger than those today, it has a very different form, which suggests that the brain has evolved more rounded over time. The dominant theory holds that behavioral changes, such as the creation of tools and art, led to changes in the form of the Homo sapiens brain, which in turn affected the shape of the skull that protects it. However, there are numerous interrelated factors at work and little fossil evidence.
According to a new PLoS study1, the physical evolution of the human skull over the past 160,000 years was probably not caused by the brain's own evolution but rather by changes in the face brought on by dietary and lifestyle changes. The skulls of 50 hominins found in Ethiopia and Israel, including H. sapiens as well as Homo erectus and Neanderthal specimens for comparison, were digitally restored by Christoph Zollikofer at the University of Zurich in Switzerland and his colleagues in order to investigate the causes behind the transformation of the brain case.
Then, 125 examples of contemporary humans were compared to the 3D models of the 50 fossils. The researchers were able to distinguish the function of the brain in the development of the skull by contrasting the brain cases of early modern human children and adults for the first time. While the size and dimensions of H. sapiens children's skulls from 160,000 years ago were broadly identical to children today, the team was astonished to find that the adults appeared radically different from modern adults, with significantly longer faces and more pronounced features.
Zollikofer, C. P. E., Bienvenu, T., Beyene, Y., Suwa, G., Asfaw, B., White, T. D., & Ponce de León, M. S. (2022). Endocranial ontogeny and evolution in early Homo sapiens: The evidence from Herto, Ethiopia. Proceedings of the National Academy of Sciences of the United States of America, 119(32), e2123553119. https://doi.org/10.1073/pnas.2123553119