Why do people vote the way they do? We think we're voting on policy and values but how much are we influenced by simple things like a candidate's appearance?

The University of Auckland's School of Psychology has decided to put our to the test by sending photos of their faces to US survey who will rate them on the basis of how trustworthy and competent they appear.

Head of Psychology Professor Will Hayward says research done overseas shows that judgements based on looks alone often align surprisingly closely with actual election outcomes.

"There is a lot of literature that shows politicians who have gone on to win an electoral race are the ones rated higher in this type of ."

The survey will use market research tool Amazon Mechanical Turk and all of the major party political candidates for the 2014 will be included. Because the study will recruit participants from the US, survey participants will know nothing about the candidates.

"So the point is that any judgements have nothing to do with policy, and are only based on whether this face looks like someone you think you'd trust to get things done," says Professor Hayward.

"One of the surprising things about this type of survey is that it has been found to produce results that you would get if you used a more orthodox sample - handing out questionnaires to undergraduate students for example."

School of Psychology Lecturer Danny Osborne says there are pools of people in the US who take part in this type of survey work regularly and are paid a small amount.

"It will be really interesting to see how an overseas audience assesses our politicians using their faces alone. Indeed, by sampling participants from overseas, we can avoid all the partisan biases that may influence the results had we conducted the study in New Zealand."

The results of the will be compared to political polls in the lead-up to the election and final results will be released after the election.

"We think it will be useful in getting people to think about how they vote and what they base their preferences on," Professor Hayward says. "We are all influenced by this stuff so it's good to keep that in mind as people think about who they are going to vote for and why."

The final results in some electorates could be an eye-opener.

"Epsom is going to be fascinating."