My colleague and friend Todd Leventhal has written a paper about conspiracy theories and disinformation, which I include at this link. I recommend you read it. Todd is one of the foremost experts in this field and unlike many who study it only academically; Todd has been in the trenches.
I first became aware of Todd in the 1980s when I was assigned to Brazil. Those were still Cold War years and despite – maybe because of – glasnost the KGB was particularly active in spreading lies and planting stories in media worldwide. I had to address lots of Soviet disinformation in the my local media. Todd’s information helped me smack down at least some of the silliness.
Especially troubling and pervasive was the story cooked up by the by KGB that the U.S. had created the AIDS virus as a bioweapon. The story still resurfaces from time-to-time. It was fairly easy to debunk, since there were so many inconsistencies in the time-lines and the biology involved, but most of those who pass along conspiracy theories are not very bright or they are malicious, so that facts have less impact on them than you might imagine. Nevertheless debunking these things early and often limits their spread. It is like pulling weeds in a garden. It is not much fun and you are never done, but you have to do it.
Read the paper. Todd discusses why and how rumor spreads. Of course, false information often proliferates in the same ways that accurate information does and we have to be self-aware enough to understand that much of what we believe at any one time is not accurate. So just thinking about these things in the way Todd does is a useful therapy for the hubris that we self-designated smart guys (wise guys?) often suffer. It is also useful to recall that false information often seems to make more sense than truth, since the lies can be modified to make a more coherent narrative.
There is a consistent human tendency to believe that big results must have had big causes. When a great leader is killed by a lone-gunman, we almost instinctively inflate the assassin to the size of his target. This kind of mental matching is usually unwarranted and it is not harmless, since it elevates little villains to iconic status and helps make political violence more successful.
Anyway, I will pass along to Todd any comments you want to make. It is worth reading his paper.