Why do many conservatives refuse to admit that climate change is real and caused by human activity?  Why do many liberals refuse to admit that the world is a dangerous place?  Why does it seem that America is divided more than ever?

We are joined by Professor John R. Hibbing of the University of Nebraska, co-author of Predisposed: Liberals, Conservatives and the Biology of Political Differences.

Professor Hibbing contends that left and right orientations are not grounded in a person's upbringing or culture, but that whether a person is liberal or conservative grows from a set of psychological, cognitive, physiological and genetic interactions which produce a spectrum of predispositions.