Wearing sunglasses makes people more likely to ogle.
Researchers have found that those in shades lech over the scantily clad more often and for longer as nobody can see them doing it.
The participants were secretly filmed doing the test while wearing sunglasses and also spectacles with clear lenses. When people wore the see-through glasses - they kept their gaze on the clothed figures. But once the shades went on, they ogled the undressed models for 20 per cent longer.
The study involved 52 men and women aged between 18 and 28.
Professor Veronica Dudarev, from the University of British Columbia in Canada, said: "People spontaneously looked more and for longer at the sexually provocative images when their eyes were camouflaged by sunglasses."
Sex therapist Phillip Hodson added: "Whether we are on the beach or in the pub, our eyes home in explicitly on bottoms and bosoms. It's mainly an unconscious quest driven no doubt by the force of the mating game."