In other words, they must hang onto their primitive weapons and crude competitive instincts, but also evolve powerful brains.

Our hominidae and Homo (genus) ancestors evolved large and complex brains exhibiting an ever-increasing intelligence through a long and mostly unknown evolutionary process.

Why did automatic, hand-me-down mammals like our ancestors somehow evolve brains with the ability to consider, imagine, project, compare, abstract, think of the future?

The ancestors of modern humans evolved large and complex brains exhibiting an ever-increasing intelligence through a long evolutionary process (see Homininae).

Researchers are interested in figuring out how mammals evolved such large and complex brains.

Human beings didn't evolve brains in order to lie around on lakes.

They walk on two legs, evolve bigger brains, and eventually, they rule the planet.

Some anthropologists believe that one reason we evolved such big and intricate brains was precisely to help us deal with the omnivore's dilemma.

So we now have two obvious questions to think about: 'Why did we evolve big brains?'

They were evolving larger brains and making more stone tools.