13/02/2017 6:30 PM AEDT | Updated 13/02/2017 8:53 PM AEDT

Staring Into Someone's Eyes Could Make You Appear More Familiar

A trick of the eye could cause trouble for police line-ups.

Supplied/University of Sydney
Who do you think looks the most familiar?

A trick of the eye could be misleading eyewitnesses in line-up identification tasks, according to new research.

A study published by the University of Sydney has shown direct eye contact between two people could increase the chance an individual incorrectly finds the face of the other person familiar.

In a series of recognition experiments conducted by the university's School of Psychology, it was found that a person has a higher chance of being identified if they stared directly into another person's eyes.

Lead author of the study, Dr Jessica Taubert, said: "In line-up recognition tasks, the face looking directly at you is more likely to look familiar than faces looking away from you – this leads to more misidentification errors for direct gaze faces."

According to Taubert, the human brain is geared so that individuals possess a natural bias towards direct eye contact, so long as the eyes remain open.

The study found that familiarity between individuals lessened when the eyes were closed or were averted so that one individual was looking away from another.

So why does this matter?

For police line-ups, it matters quite a lot. It means there's more that happens in our brains when it comes to facial recognition than we know.

Line-ups are a common method of identification for police when it comes to witnesses or victims pin-pointing potential criminals when technology such as fingerprint recognition is not an available option.

Generally, suspects stand in a line in front of a witness, who attempts to identify them. This means the suspects further from the middle of the line are looking at the witness from a slightly different angle.

In other words, if you ever find yourself in a line-up and you draw the unlucky middle spot and happen to meet eyes with the witness opposite you, you're more likely to be picked -- even if you're innocent.

For co-author of the study, Dr Celine van Golde, this mix-up comes as a result of an overconfidence humans have developed when it comes to facial recognition.

"People tend to overestimate how well they can recognise faces. We believe that because you can recognise your friends, family and familiar people so quickly and easily, confidence is inflated when faces are unfamiliar," she said.

"This overconfidence is one reason why eye gaze had not been explored as a factor before, even though it is well-known to influence vision and memory."

When it comes to possible solutions, Taubert and van Golde both agree that changes to the line-up or the setting could have an influence and lower misidentification. Until then, it seems the mistake will always lie in the eyes.