Hopkins and his team have focused their research on chimpanzees, mainly due they say, to the fact that chimps are our closet living relative and that they are the only other species besides humans that regularly throw things with a clear target in mind. He and his team have been watching chimps in action for several years and comparing their actions with scans of their brains to see if there were any correlations between those chimps that threw a lot, and those that didn’t or whether they’re accuracy held any deeper meaning. Surprisingly, they found that chimps that both threw more and were more likely to hit their targets showed heightened development in the motor cortex, and more connections between it and the Broca’s area, which they say is an important part of speech in humans. The better chimp throwers, in other words, had more highly developed left brain hemispheres, which is also, non-coincidently, where speech processing occurs in people.

Such findings led the term to suggest that the ability to throw is, or was, a precursor to speech development in human beings.