Terry Gross

Project Nim is the new documentary about a chimpanzee raised in a human household as part of an experiment to see if chimps could learn language. Director James Marsh and two of the people who cared for Nim talk with Terry Gross about the controversial study.

Welch and Rawlings perform an in-studio concert featuring several songs from The Harrow and the Harvest, and talk about many of the lyrics they've written over the years.

Neuroscientist Dean Buonomano explains why our brains make mistakes when we try to remember long lists of information or add large numbers in our heads. Humans live "in a time and place we didn't evolve to live in," he says.