Far from being dimwits in tin hats - a new book suggests there is a conspiracy theory in all of us. Author and psychology professor Rob Brotherton talked to Nine to Noon about his work.
His book, Suspicious Minds: Why We Believe Conspiracy Theories, seeks not to debunk or support conspiracy theories, but to understand what about them is so attractive to people.
Mr Brortherton said it was very hard to define what a conspiracy theory was, as there was no clear black and white definition, although some theories were more plausible than others.
One of the most widely believed conspiracy theories, currently, is that the 9/11 attacks were an inside job.
Mr Brotherton said surprising numbers of people agreed with various versions of the theories.
"So if you ask people simply 'do you think the American government isn't telling the whole truth about the attacks?' then about half the American public agree with that, according to some surveys."
Mr Brortherton said there was a stereotype that conspiracy theorists were a small, paranoid fringe of people, but research indicated that wasn't the case.
"In fact what the research shows is that conspiracy theories, or conspiracy thinking, seems to be wired into our brains. It's how our minds work."
He said our brains were wired to assume that when something big happened in the world, there must have been a proportionately significant cause.
A perfect example was conspiracy theories about the assassination of John F. Kennedy, he said.
Many conspiracy theorists believe Lee Harvey Oswald didn't work alone in his assassination of the US president.
"Perhaps part of the reason is that we are wired to assume that just one guy... could just get out of bed that day and change the course of history. That doesn't sound plausible according to this bias.
"So then we hear conspiracy theories...and that seems more plausible according to this proportionately bias."
But Mr Brortherton said there was no way to disprove conspiracy theorists.
"Any evidence that we see... can be interpreted as consistent with their theory.
"So if there's no evidence at all to support the theory, you'd expect that because the conspirators are covering it up."
He said there were some conspiracy theories that influenced people's choices, such as those around vaccines.
"We've seen the consequences of that around the world. We've seen these outbreaks of measles and other preventable diseases as a response to the conspiracy theories that urge people to leave their children vulnerable to these diseases."
Mr Brotherton said his approach with his book wasn't to debate the facts of conspiracy theories.
"Maybe they're true, maybe they're not. We're not interested in that... what we're trying to answer is why might people believe them, regardless of whether they're true or not.
"If there was a conspiracy theory we'd all like to know about it. But we don't want to believe things without good reason."
Listen to Rob Brotherton speaking to Lynn Freeman on Nine to Noon: