Here’s an interesting study on belief in conspiracy theories:
Conspiracy theories can form a monological belief system: A self-sustaining worldview comprised of a network of mutually supportive beliefs. The present research shows that even mutually incompatible conspiracy theories are positively correlated in endorsement. In Study 1 (n = 137), the more participants believed that Princess Diana faked her own death, the more they believed that she was murdered. In Study 2 (n = 102), the more participants believed that Osama Bin Laden was already dead when U.S. special forces raided his compound in Pakistan, the more they believed he is still alive. Hierarchical regression models showed that mutually incompatible conspiracy theories are positively associated because both are associated with the view that the authorities are engaged in a cover-up (Study 2). The monological nature of conspiracy belief appears to be driven not by conspiracy theories directly supporting one another but by broader beliefs supporting conspiracy theories in general.
Based on this, one might be tempted to think that conspiracy theorists are just crazy! How can they simultaneously believe contradictory things?
Maybe they are crazy, of course, but these data don’t actually provide strong evidence for it. The problem is that the abstract uses a shorthand that seems quite reasonable at first but is actually a bit misleading. Instead of saying
The more participants believed that Princess Diana faked her own death, the more they believed that she was murdered.
They should say
The more participants believed that Princess Diana might have faked her own death, the more they believed that she might have been murdered.
That’s what the surveys probably revealed. They asked people to rate their belief in the various statements on a 7-point Likert scale from “Strongly Disagree” to “Strongly Agree”. Anyone who gave strongly positive responses (say 6’s or 7’s) to two contradictory options would indeed be irrational, but as far as I can tell the results are consistent with the (more likely, in my opinion) scenario that lots of people gave 3’s and 4’s to the various contradictory options. And there’s nothing irrational at all about saying that multiple mutually contradictory options are all “somewhat likely.”
In fact, although the positive correlation between contradictory possibilities is amusing, it’s actually not surprising. The last couple of sentences of the abstract lay out a sensible explanation: if you’re generally conspiracy-minded, then you believe that shady people are trying to conceal the truth from you. Given that premise, it’s actually rational to bump up your assessment of the probabilities of a wide variety of conspiracies, even those that contradict each other.
I’m not saying, of course, that the original premise is rational, just that the conclusions apparently being drawn are rational consequences of it.
And I should add that, as far as I can tell, a careful reading of the paper indicates that the authors understand all this. A quick reading of the abstract might lead one to the wrong conclusion (that conspiracy theorists simultaneously believe contradictory things), but on a more careful reading the paper doesn’t say that.