There’s a lot we’re still learning about our closest evolutionary relatives. In the past year, scientists have discovered that chimpanzees have many traits long considered uniquely human. They form relationships based on trust, de-stress by hanging out with friends, raise their children with the help of “babysitters,” and (as shown in the video above) directly teach their kids foraging skills. This transformation in primate research has, in part, been due to advances in technology—discovering how chimps teach their offspring to use tools may have been impossible without remote observation capabilities. But in part, it’s cognitive. That’s what Dutch primatologist Frans de Waal argues in his recent book, Are We Smart Enough to Know How Smart Animals Are? One of the biggest impediments to studying animals has been our confidence in our superior intelligence, de Waal says, which researchers now recognize as misguided. That’s all changing, he writes: “Nothing is off limits anymore, not even the rationality that was once considered humanity’s trademark.”