Imagine an election without facts. What if that's where we are heading?

Both the ABC and politifact.com.au have set up ''fact-checking units'', innovations that would have once been welcomed. After all, without facts, how can you work out how to vote? But the new institutions have been met with scorn. The Australian newspaper has run commentary asking whether the units will check facts from a ''green-left'' or ''so-called progressive'' point of view. A Coalition senator has pointed to tweets made by the man who now heads the ABC's unit and asked how he can check facts when he has attacked the Coalition.

It is as if facts don't exist independently of views - as if there are green-left facts, pro-market facts, pro-business facts, but not simply facts that are able to be dug up by anyone regardless of their political persuasion.

It is true that Labor voters give pollsters a very different account of economic facts to Coalition voters.

The Melbourne Institute has been surveying consumer sentiment for decades. Among the questions it asks is whether economic conditions are improving or getting worse. Every month without exception for six years now Labor voters have been reporting brighter conditions than have Coalition voters.

But if you look back to just a month before Rudd was elected you see something remarkable. For every month under John Howard as far back as the eye can see, the Labor voters reported worse conditions than the Coalition voters. The two switched their perception of the economy as soon as their side took (or lost) office.

It can't be because the economy suddenly changed. The switch is too dramatic. And if the facts had suddenly changed, the perceptions of voters on both sides of politics would most probably have moved in the same direction.

We are increasingly self-selecting our ''news''. Whereas once one single set of news was presented to the nation each night at 7 o'clock and just a couple of sets each morning in the newspapers, these days we are tailoring our own news feeds, relying heavily on Twitter, web searches and sometimes openly partisan newspapers and radio stations.

Does that give us even less of a handle on reality? There are worrying signs that it does.

The US went down the tailored-news road early with Fox News, an openly partisan cable channel totally unlike Sky News in Australia.

The ''facts'' that its viewers outline to pollsters are far more likely to be false than those who rely on old-style media.

After the initial phase of the Iraq War in 2003, Americans were asked whether or not US forces had found the much-talked-about Iraqi weapons of mass destruction.

An astounding 33 per cent of those who relied on Fox News falsely said they had. Among those who relied on the traditional networks, the proportion was only 20 per cent. Among those who relied on public broadcasting it was just 11 per cent. Other findings in the survey suggest that the more an American watches Fox News the more likely she or he is to believe things that are false. It would be deeply concerning, were it not for the findings of an ingenious new survey released in May.

Researchers from Yale University and the University of California, San Diego, wondered whether the Americans reporting false beliefs really held them or were just ''barracking'', having a lend of the surveyors to make a political point.

Their genius was to pay for correct answers. Without payments, Republicans and Democrats were sharply divided in their responses to factual questions such as whether American deaths in Iraq were increasing and whether or not the world was warming.

But with small payments ($1 for the correct answer and 33¢ for using the option ''don't know''), almost all of the gap disappeared.

The proportion admitting they didn't know became huge, up to 50 per cent.

When tested with money, Americans appear to have a surprisingly good idea about what they don't know, and when they do take a stab at something they are likely to guess the truth.

The researchers disparage polling of the kind conducted in Australia, saying: ''Just as people enjoy rooting for their favourite sports team and arguing that their team's players are superior even when they are not, surveys give citizens an opportunity to cheer for their partisan team.''

There's a chance deep down we are hard-wired to know what is a fact and what is not, even if we don't let on. There's a chance we will take seriously the work of the fact-checking units even if some of the barrackers say they will not.