Portsmouth Study: Eye Movements Show If We Know Someone

25 March 2017, 09:08

Portsmouth Uni researchers claim tiny eye movements can reveal whether a police suspect knows someone.

Their study found a different pattern when we see a face we recognise.

It's hoped it could help detectives with questioning gangs and terrorist cells.

Psychologist Ailsa Millen, from the University of Portsmouth, who led the study, said: 

``Criminal accomplices often deny that they know other members in their networks.

``However, if a co-conspirator denies recognition in this way, their eye movements when viewing photos of those suspects may reveal this type of lie.''

Experiments using eye-tracking technology showed that people's eyes move in a different pattern when looking at faces they recognise.

Scientists recorded the eye movements of 59 volunteers who were asked to view 200 digital colour photos of familiar and unfamiliar faces.

Familiar faces included people the participants knew in real life, famous celebrities and other individuals briefly seen before the trials began.

Sometimes, the volunteers lied about whether they recognised the faces and on other occasions, they told the truth.

Ms Millen said: 

``We found that people's eye movements were different when looking at photographs of faces they knew well, compared with those they did not know, despite verbal reports denying recognition.

``When a participant looked at a face, they recognised their eyes moved in a different pattern with fewer fixations. There is substantial evidence to suggest that this pattern is involuntary, which means it could be hard to control or fake.

``This research could be valuable to police when trying to confirm key identities in criminal networks such as terrorist cells or gangs.''

The findings are to appear in a special edition of the Quarterly Journal of Psychology.