Many people seem to think there are aliens at Area 51-- but did you ever wonder why conspiracy theories about the area are so popular? Psychologist Karen Douglas says nearly all conspiracy theories satisfy three basic needs: they provide understanding and certainty, they create a sense of control, and they improve a believer's self-image. As a general rule, humans do not like nagging uncertainty, so even an outrageous answer is better than none at all. With that answer comes a greater sense of knowledge and safety, and since many people don't necessarily believe a conspiracy theory, there is a feeling among believers that they are part of a uniquely well-informed minority. But theories about Roswell, New Mexico, and Area 51 are particularly contagious because they've been around for decades, and show up across pop culture in TV shows, books, movies and more.