Pollsters and politicians take note: new research says people who consciously see themselves as "undecided" may have already made up their minds, even if they don't realize it.

Testing people's ingrained attitudes through automatic mental associations may be a better indicator of future preferences than polling their consciously held beliefs, according to the authors of a study published Friday in the journal Science.

Automatic mental associations are biases that influence us, but they aren't necessarily unconscious biases, said Bertram Gawronski, Canada Research Chair in Social Psychology at the University of Western Ontario.

What is unconscious is how these associations can impact our decision making process, he said.

"This biased perception of reality can create the basis for future decisions without our awareness," said Gawronski, who worked on the study alongside a graduate student and professor at the University of Padova in Italy.

The team of researchers based their findings on tests of 129 residents of Vicenza, Italy. Residents were given three tests. They were polled about a controversial enlargement of an American military base in their community, polled about their conscious beliefs on a wide range of issues and also given automatic mental association tests.

In the association tests, participants were asked to quickly categorize a series of words as either positive or negative, interspersed with pictures of the base. They were also timed on how quickly they were able to answer. Users who had a negative perception of the base, for example, were more likely to take longer identifying a word as positive if the word was accompanied by a picture of the base.

The group was polled and tested a second time one week later, with undecided voters asked to make a final decision on whether they supported the base.

While the conscious beliefs played a huge role in the choices of decided voters, they had no correlation to the undecided voters, the study found.

How a person scored on the automatic mental association test, however, had a strong statistical correlation on how an undecided person voted, said Gawronski. While not built to provide predictions per se, the test did enable researchers to predict the future choices of 70 per cent of participants who initially said they were undecided.

The researchers found the relationship between conscious beliefs and automatic responses is not a one-way street, however. Decided participants performed more in line with their conscious beliefs when they took a second automatic associations test.

This, said Gawronski, suggests that the conscious decisions we make can over time influence our underlying biases.

"This brings up the idea that once people know their biases, they can reflect on certain things and influence their automatic reactions," he said. "One doesn't want to be a slave of our automatic responses."