On this week's show -- it’s sink or swim. First up, Sean B. Carroll on Charles Darwin and the early days of survival of the fittest. Then, neuroscientist and author Daniel J. Levitin explains how to tackle modern-day information overload. We'll hear from Robert Kurzban on humans as political animals, and why we don't always make decisions in our best interest. Plus, commentator Clive Thompson on why politicians should "eat their own dog food."