Biologists have debunked previous beliefs about the evolution of the human brain.

Modern research consistently offers new insights into brain development across various biological species. For instance, the fossils of Australopithecus Little Foot—one of the most renowned representatives of ancient humans—have shown how this organ evolved in hominids. Additionally, an experiment involving brain organoids from primates—demonstrated that the development of the brain in humans was determined by just one mutant gene.

Experts from the University of Reading and Durham University (both in the UK) analyzed data on ancient human fossils spanning seven million years. Using statistical methods, they filled gaps in the fossil record and refuted long-standing beliefs about the evolution of the human brain. The scientific article detailing the research findings was published in the journal Proceedings of the National Academy of Sciences.

It turned out that the brain size of each ancient human species increased gradually rather than through abrupt leaps between species. Previously, it was thought that, for example, Neanderthals were incapable of adaptation; however, it is now clear that the driving force behind brain size evolution should be viewed as gradual and continuous changes.

“This research fundamentally alters our understanding of how the human brain evolved. It was previously believed that brain size among different species varied sharply, similar to updates of the latest computer models. Our work reveals a constant, gradual ‘software update’ occurring within each species over millions of years. <…> Major evolutionary changes do not always require dramatic events. They can happen through small, incremental improvements over time, much like how we learn and adapt today,” explained the authors of the article.

The researchers also noted that differences in brain size observed among individual species did not always correlate with body size, although larger species typically have larger brains. This characteristic emphasizes that brain development over long evolutionary periods is influenced by factors distinct from those that are significant for individual species.