What makes us different from our ancestors the apes and primates? The genetic mutation that gave rise to the human also gave us curiosity. This fascination with the world around us, Swimme explains, may be the defining characteristic of what it means to be human. Our capacity for wonder, awe, play and astonishment eventually lead to an ability to share those experiences with language. With the development of language comes a change in life itself, as learning now becomes part of the evolution of our species.