It is quite amazing that some of the smartest people in the world can believe some of the strangest things. The IQ of someone doesn't asses their ability to think scientifically. People with high IQ's are at least as prone as other people to beliefs in conspiracy theories. It goes to show you that just because someone believes in an outrageous theory doesn't mean that they are unintelligent. One of the main reasons that this is, is because people with higher intelligence are better at creating or proving that their theories are sounder then the ones they are arguing against. This means that once they believe in a certain theory then they are extremely likely to have confirmation bias and push the facts against their thought out of their minds. Also people with a high IQ are more likely to have a sense of omniscience or thinking that they know everything. Since they know a lot of things they feel that they know everything about everything, especially when they are comparing themselves to the amount that other know. A perfect example of this is Sir Arthur Conan Doyle who is famous for creating Sherlock Holmes, fell for a trick by a couple of girls and actually wrote a book defending the girls when they said they were with fairies. Later on the girls confessed that they were lying. This is just a preview of this book but it shows exactly what I am saying. http://www.scientificamerican.com/article.cfm?id=smart-people-believe-weir This is showing that smart people do things without weighing out all of the pros and cons but rather by going by what they already know and because they are good at defending their beliefs.