There was a great Skeptic column in the September ScientificAmerican. Michael Shermer talks about people who believe in two conspiracy theories that are directly contradictory, but don’t seem bothered by it. For example, there are people who believe Princess Diana faked her own death and also believe that it was an MI6 conspiracy. There are people who believe that UFOs are secret DARPA projects and also that aliens are visiting earth.
How can anyone believe in contradictory conspiracy theories? Are they just stupid? Or brain damaged? Or have their brain wires crossed? Nope. There is actually a more logical explanation that has received evidence in a recent study by some psych researchers at the University of Kent (that Shermer cites).
Here is how it works. These individuals have a global schema such as “there are powerful people behind the scenes who are pulling the strings of these important events.” This is their conspiracy theory. Then each of these specific events could be true. Maybe not all of them. But since the conspiracy theorist doesn’t have specific evidence he/she can be sure that at least some of them are true. Maybe Diana couldn’t have faked her own death and be killed by MI6, but one of those is true. They are just using an OR operator rather than an AND.