Researchers at Bristol University came to their conclusions after asking volunteers to examine a range of different images, including pictures of couples in films, The Daily Telegraph reported Friday.
They found women spent 61 percent of their time looking at the women in the pictures, and only 39 percent on the men, while men seemed to spend just over half -- 53 percent -- of their time looking at the women.
"This is counter-intuitive from a sexual perspective if you are thinking about desire, but it's not surprising if you look at it in terms of sexual competition," said Felix Mercer Mos, a computer science doctoral student who led the study. "The women might be checking out their sexual rivals and comparing themselves with them."
He noted: "That's speculation of course -- I've no proof whatsoever."
The study also found that while men concentrated on the faces of the women, women's eyes tended to roam around the whole figure.
Kate Figes, author of books on relationships, said she wasn't surprised by the study's findings.
"We are always sizing ourselves up against the competition," she said. "It's because we feel threatened. It's quite a basic animal state. I'm sure if the gender states were reversed, men would do exactly the same."