Supporters of US President Donald Trump are more likely to believe what he says, and even after they are shown it is not true, they still want to vote for him, research has shown.

The University of Western Australia study was undertaken by researcher Briony Swire-Thompson and School of Psychological Science associate professor Ullrich Ecker in late 2015 as the US election campaign was ratcheting up in intensity and rhetoric.

Researchers gave more than 2,500 Republican and Democrat participants a selection of Mr Trump's statements and asked whether they believed the statements, some attributed to him, others not.

"If they knew the information was from Trump, Republican supporters believed the information more and the opposite was true for Democrats, as soon as they heard it was from Trump, it didn't matter if it was true or false," he said.

He said when the subjects were told the information was fake, it had some effect, but did not really change their voting intention.

The researchers were also surprised Trump supporters became confused about what was true or false, even after being told.

"As soon as the information was associated with Trump, people got confused and after a week or so they had a hard time remembering what was true or false," he said.

"That was surprising, that once statements were associated with Trump, it seemed to impair their memory for the statements they had read and rated," he said.

Fed up with normal politicians

Mr Ecker said many people were "fed up" with politicians and did not want politicians to "tiptoe" around issues, but it meant vulnerable people might be exploited.

"People in desperate situations, who are feeling left behind and neglected by the existing system, they become vulnerable to leaders who may not have their best issues at heart," he said.

"If people feel they are being left behind and are having trouble putting food on the table, they long for strong leaders and then fall for [those] leaders.

"We're kind of used to politicians cherry-picking and twisting the truth a little bit, but this was a new quality, not only in the US but also in the UK, politicians were saying outright false things, and getting away with it."

Social media echo chamber?

Mr Ecker said the ubiquity of social media allowed people to exist in political "echo chambers", and their views and opinions were rarely challenged.

"The rise of social media means people can choose more readily what to believe because they can find support for whatever they want to believe if they go to the right place online," he said.

"People like Trump are using social media such as Twitter to speak their mind, they are using the people's language."

Mr Ecker said the rise of this type of discourse could be seen in Australia as well, with the popularity of One Nation and non-traditional politicians.

"The mining boom has ended, people are unhappy and unemployed," he said.

"People in that situation are vulnerable to promises and of people getting up and saying 'it is the fault of this group."