Diane Benscoter devoted five years of her life to being a Moonie, a follower of Sun Myung Moon. After years in the church (which she now refers to as a cult), Benscoter left and became a "deprogrammer" (...until she was arrested for kidnapping in connection with a deprogramming attempt). In this TED Talk from early 2009, Benscoter describes her history, a bit about deprogramming, and how being a Moonie changed her brain -- the specific logical process that led her to lock into the cult's mindset, bypassing critical thinking. This is a quick talk (just over six minutes), but it raises some interesting points about why cults work; you can read a long Q&A with Benscoter to get more depth on her experience.
Discussed: how cults work psychologically, why people in cults think they need to save the world, viral memetic infection (hello Snow Crash).
Representative quote: "These easy [answers] to complex questions are very appealing when you're emotionally vulnerable.... Circular logic takes over."
WARNING: there are a few graphic images depicted in this talk (related to Jonestown and terrorism).