Trejo's made a career playing menacing tough guys, from 'Sons of Anarchy' to 'Machete.' He says that his experience standing in the yard waiting for a prison riot in San Quentin prepared him for acting: "You're absolutely scared to death ... [but] you have to pretend you're not." Critic Maureen Corrigan reviews two books about cold cases. In recent years, artificial intelligence technology has evolved at a rapid pace. Computers can now mimic human language and drive cars. 'New York Times' technology reporter Cade Metz discusses how computers can learn on their own, what their limitations are, and the dangers of them making mistakes.