New research led by Dr Thomas Püschel overturns long-standing ideas about human brain evolution
Modern humans, Neanderthals, and other recent relatives on our human family tree evolved bigger brains much more rapidly than earlier species, a new study of human brain evolution has found. The study, published in the journal
PNAS, found that brain size increased gradually within each ancient human species rather than through sudden leaps between species.
Researchers assembled the largest-ever dataset of ancient human fossils spanning 7 million years and used advanced computational and statistical methods to account for gaps in the fossil record. These innovative approaches provided the most comprehensive view yet of how brain size evolved over time. The research challenges old ideas that some species, like Neanderthals, were unchanging and unable to adapt and instead highlights gradual and continuous change as the driving force behind brain size evolution.
Dr Thomas Püschel, Associate Professor in Evolutionary Anthropology at the School of Anthropology and Museum Ethnography, lead author of the study, said: “Big evolutionary changes don’t always need dramatic events. They can happen through small, gradual improvements over time, much like how we learn and adapt today.”
Professor Chris Venditti, co-author of the study from the University of Reading, said: "This study completely changes our understanding of how human brains evolved. It was previously thought that brain size jumps dramatically between species, like new upgrades between the latest computer models. Our study instead shows a steady, incremental ‘software update’ happening within each species over millions of years.”
The researchers also uncovered a striking pattern: while larger-bodied species generally had bigger brains, the variation observed within an individual species did not consistently correlate with body size. Brain size evolution across long evolutionary timescales extending millions of years is therefore shaped by different factors to those observed within individual species – highlighting the complexity of evolutionary pressures on brain size.
The study, completed while Dr Püschel was at the University of Reading, was produced as part of a £1 million Research Leadership Awards grant from the Leverhulme Trust. The project was to better understand the evolution of human ancestors.
Read the full study: Püschel, T. A., Nicholson, S. L., Baker, J., Barton, R. A., & Venditti, C. (2024). Hominin brain size increase has emerged from within-species encephalization. Proceedings of the National Academy of Sciences, 121(49), e2409542121.
