A recent study published in the Proceedings of the National Academy of Sciences has shed new light on human brain size expansion, challenging the idea of a single driver for this phenomenon. Researchers led by Thomas Püschel at the University of Oxford analyzed fossils from early human ancestors and found that brain growth occurred gradually within individual species over time.
Contrary to previous assumptions, the study suggests that brain size increased in response to a mix of genetic, environmental, and behavioral factors rather than a single cause. The analysis also revealed that this process accelerated in more recent human ancestors.
Püschel’s team used advanced computer models to estimate missing details from incomplete fossils and found that while larger-bodied species often had bigger brains, brain size and body mass didn’t always increase together. Instead, brain growth tended to occur gradually within individual species, influenced by a combination of genetic, environmental, and behavioral factors.
The researchers propose a feedback loop where social, cultural, and technological advancements reinforced brain growth, potentially leading to co-evolutionary relationships between cognitive capacities and complex behaviors. This theory suggests that greater cognitive abilities allowed for more complex behaviors, which in turn further selected for larger brains.
Future studies will continue to analyze the dataset, incorporating environmental and climatic predictors to explore how these factors may have influenced brain evolution. Preliminary evidence suggests that colder temperatures may have driven encephalization within species by promoting adaptations against hypothermia.
Source: https://bigthink.com/the-past/how-early-human-brains-expanded-over-time