Cara is joined by famed neuroendocrinologist Dr. Robert Sapolsky, author of the new book "Behave: The Biology of Humans at Our Best and Worst." They discuss the interplay between neurobiology, environment, development, and evolution in our decision-making processes, for better or worse. In seeking to understand why we do what we do, Dr. Sapolsky describes the very essence of what it means to be human.