For the past 2 million years, the size of the human brain has tripled, growing much faster than other mammals

niversity of Missouri researchers studied three common hypotheses for brain growth: climate change, ecological demands and social competition

The team found that social competition is the major cause of increased cranial capacity.

Our findings suggest brain size increases the most in areas with larger populations and this almost certainly increased the intensity of social competition

When humans had to compete for necessities and social status, which allowed better access to these necessities, bigger brains provided an advantage

"Brains are metabolically expensive, meaning they take lots of time and energy to develop and maintain, making it so important to understand why our brains continued to evolve faster than other animals