Can you communicate with someone who's sound asleep, and is it possible to influence their dreams? Ken Paller, professor of psychology at Northwestern and a leading sleep researcher, talks about "lucid dreaming" — the state of dreaming while knowing you're in a dream — as well as about how researchers can reach into the brain of a sleeping person and actually create the experience they have in their dreams. Is it ethical to influence the dream state? What are the implications for brain health if we can never turn off Plus... "Sleep Learning" with the 1920s Psycho-Phone.