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, overturns long-standing ideas about human brain evolution.
The researchers found that brain size increased gradually within each ancient human species rather than through sudden leaps between species.
The research team assembled the largest-ever dataset of ancient human fossils spanning 7 million years.
They 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.
It 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.
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.
This highlights the complexity of evolutionary pressures on brain size.
The research team involved Professor Robert Barton from our Department of Anthropology and was led by scientists from the University of Reading and the University of Oxford.
The study 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.
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