British scientists unveiled research indicating that the human brain grew slowly over millions of years, occurring gradually within each species of ancient humans and contradicting previous beliefs of sudden growth. The study, a collaboration between the universities of Reading, Oxford, and Durham, challenges earlier theories that posited sharp changes in brain size between species, emphasizing instead a steady, incremental evolution within each species.
"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," said Professor Chris Venditti, according to IFLScience. The findings suggest that the evolution of human brain size was driven by gradual changes rather than sudden leaps linked to major evolutionary events.
The research team conducted the largest study of fossil human skulls to date, covering a time span of seven million years. This extensive analysis led to new insights that challenge previous interpretations of skull remains. By using a more complete sample of the fossil record than earlier studies, the scientists were able to compare different growth patterns and address uncertainty with advanced statistical techniques.
Dr. Joanna Baker, co-author of the study, emphasized the importance of understanding the evolution of brain size within the context of human evolution. She noted that the emergence of large brains in humans was primarily the result of gradual changes within individual species over millions of years.
The research revealed that larger-bodied species tended to have larger brains, but within the same species, variation in brain size was not consistently correlated with body size. This indicates the action of factors beyond simple dependence on body size.
"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," said Dr. Thomas Puschel of Oxford University.
The study also found that the brains of Neanderthals grew consistently throughout their history, challenging the idea that they were unable to adapt. This research disputes established beliefs that some species, like Neanderthals, were immutable and incapable of adapting, demonstrating the gradual evolution of human brain size.
The results of the study were published in the Proceedings of the National Academy of Sciences (PNAS). The research provides insights into the evolutionary processes that have shaped the human brain, demonstrating how small changes can accumulate over time, leading to evolutionary achievements such as the development of large and complex brains in modern humans.
This article was written in collaboration with generative AI company Alchemiq