Due to the Internet, conspiracy theories are on the rise and playing an increasingly significant role in global politics. Now new research from The Australian National University (ANU) has analysed digital data to reveal exactly who is propagating them and why.

Lead researcher Dr Colin Klein of the ANU School of Philosophy said that conspiracies such as Pizzagate (which falsely claimed high-ranking Democratic Party officials were running a child-sex ring out of a pizza shop) and the anti-vaccination movement are becoming a bigger issue.

"Conspiracy theories are on the rise and that's a problem. Just look at the influence they have had on recent political discourse," Dr Klein said.

"Over time these conspiracies start to break down public trust in things like governments, institutions and even doctors."

Dr Klein and his team used a huge, publicly available dataset of every comment made on the conspiracy section of the world's largest discussion website Reddit from 2007 to mid-2015 to work out exactly who was taking part in spreading these conspiracies and why. He was surprised by the results.

"You have to realise it's not just people who are crazy and distrust everything," he said.

"It is commonly believed that conspiracy believers tend to be the kind of people that connect every conspiracy to everything else - like the typical tin foil hat wearing stereotype.

"We found that there are those people, but they are the tip of a much larger iceberg."

The analysis showed that most conspiracies built traction when a range of different people and groups could connect it to their own preconceived beliefs or agendas.

"People have an agenda and are looking for conspiracies that can hook into it," Dr Klein said.

"The most successful conspiracies were the ones where everyone can get something out of it.

"Consider a conspiracy about secret CIA prison camps. One person might care about its relationship to 9/11, another might use it to fuel their anti-Semitism, a third to make a point about gun control.

"Each gets what they need, and each contributes to the larger whole."

The study also looked at the reasons people engaged in conspiracy theories.

"There are some people who don't even seem to believe the things they are saying. Rather, it's a way of expressing a dislike for something - like a politician or a group of people," he said.

"Pizzagate is a really interesting case, where it starts off as a form of trolling by people who didn't like Hillary Clinton, but then others were willing to pick it up seriously and take it further."

The study was conducted in collaboration with researchers from Macquarie University and was published in Frontiers in Psychology: https://www.frontiersin.org/articles/10.3389/fpsyg.2018.00189/full