Twin Tower attacks
A study has linked political extremism with conspiracy theories, such as the belief 9/11 was hatched by the US government Reuters

Political extremists are most susceptible to believing conspiracy theories, such as the financial crisis being caused by a secret deal between bankers and politicians, or the Iraq war being driven by a thirst for oil, a study has suggested.

Researchers in the United States and the Netherlands found those on the far right or left have an "increased tendency to believe in conspiracy theories".

A team led by psychologist Jan-Willem van Prooijen of VU University Amsterdam concluded the theorists believe in conspiracies as a way of "making sense of societal events".

In one study, 185 participants were asked to classify themselves on a ideological scale from extremely left-wing to extremely right-wing before confirming their level of agreement or disagreement with statements.

They were then asked to rank their agreement/disagreement with that statement "the financial crisis is the result of a conspiracy between bankers and corrupt politicians" and other theories.

In another investigation, 1,010 people were asked to rate themselves on an 11-point left-right scale level of agreement or disagreement with the statement "with the correct policies, most societal problems can be solved very easily".

The same people were then presented with six conspiracy theories - including "the political arena was infiltrated by oil companies when making the decision to go to war against Iraq" - and asked to rate them on a scale of one ("highly probable") to seven ("highly improbable").

Researchers concluded people on both sides of the left-right divide, as well as those who agreed with the policies statement, were more likely to believe in the conspiracies.

The study also suggested conspiracy theorists have a propensity to look for "clear-cut" answers and have a tendency to subvert news and opinion that differed from their own.