Tool use is often seen as a defining human trait, but animals from chimpanzees to crows also use tools. Explore how diverse species use tools and what that may reveal about intelligence across the animal kingdom.
The battle of the sexes: Whose brain comes out on top?
Popular culture loves the idea that men and women think differently, but the science is far less dramatic. Here’s what the research shows about cognitive ability and brain differences between the sexes.
The problem of brain size
Why the relationship between brain size and intelligence is so complicated