I don't remember this being discussed here before:
Examining Conspiracist Beliefs About the Disappearance of Amelia Earhart:
The Journal of General Psychology
Volume 139, Issue 4, 2012
ABSTRACT
Previous studies have suggested that conspiracist ideation forms part of a monological belief system in which one conspiracist idea acts as evidence for new conspiracist ideas. Here, we examined this possibility in relation to an event lacking reliable or conclusive evidence, namely the disappearance of Amelia Earhart and Fred Noonan. A total of 914 members of the British general public completed scales measuring their beliefs about the disappearance of Earhart and Noonan, belief in conspiracy theories, the Big Five personality factors, support for democratic principles, political cynicism, self-esteem, and self-assessed intelligence. Results showed that belief in conspiracy theories was associated with the endorsement of less plausible explanations for the disappearance of Earhart and Noonan. In addition, belief in less plausible explanations was also significantly associated with lower self-assessed intelligence, greater political cynicism, lower self-esteem, and higher Agreeableness scores. These results are discussed in relation to monological belief systems.
Unfortunately if you don't have a subscription ( or have access through a university library) you can't read the full article and I can't post it without violating copyright laws. They surveyed british citizens who no special knowledge of AE, the majority (32%) believed in the crashed and sank,the Gardner Island theory was believed by only 10%, crashing in New Guinea was believed by 11.5%, shot down by Japanese while spying 5.5%, crashed in Saipan and executed 14%,intentionally landed in Japanese area to spy and were later rescued 9.5%, returned to US under new identities 13%, and abducted by outer space aliens 4.5%.