"Feeling love for your romantic partner appears to make everybody else less attractive, and the emotion appears to work in very specific ways in enabling you to push thoughts of that tempting other out of your mind," said Gian Gonzaga of eHarmony, whose study is published in the journal Evolution and Human Behavior.

"It's almost like love puts blinders on people," added Martie Haselton, an associate professor of psychology and communication studies at UCLA.

Gonzaga and Haselton asked 120 heterosexual undergraduates in committed relationships to examine photographs of attractive members of the opposite sex from an eHarmony Web site.

The volunteers were asked to choose the most attractive photos, and write an essay either about their current romantic partner, or the subject of their choice. While writing, the students were asked to forget the "hotties" from the Web site, but told to put a check in the margins if they did happen to think of the attractive photos.

The volunteers who wrote about their partners were six times less likely to admit to thinking of the attractive others than volunteers who wrote about random subjects.

And later, when asked to recall the cuties in the pictures, the students who wrote about their lovers remembered fewer details about the physical appearance of the attractive strangers.

"These people could remember the colour of a shirt or whether the photo was taken in New York, but they didn't remember anything tempting about the person," Gonzaga said.

"It's not like their overall memory was impaired; it's as if they had selectively screened out things that would make them think about the how attractive the alternative was."

Is love really blind? Tell us what you think in the comment box below.