What happens when fake news stories motivate real-world behavior?

Conspiracy theories thrive on the internet. A frightening incident at a Washington pizzeria last week is ramping up concern of the real-world implications of fake news stories. Joseph Parent, co-author of "American Conspiracy Theories" -- also a political science professor at the University of Miami -- and CBS News legal analyst Rikki Klieman join "CBS This Morning: Saturday" to discuss why people believe in conspiracy theories and possible ramifications.