© ISTOCKPHOTO / ALiJA

If your loved one claims to “only have eyes for you” this Valentine’s Day, it might be truer than you think. Research shows that people in a committed relationship who have been thinking about their partner actually avert their eyes from attractive members of the opposite sex without even being aware they are doing it.

Psychologist Jon Maner of Florida State University and his colleagues flashed pictures of faces on a computer screen for half a second, following it immediately with a square or circle, which participants had to identify by pushing the correct button. Earlier research using this method has found that it takes longer for viewers to shift their attention away from attrac­tive faces of the opposite sex.

Maner, however, took subjects who were married or living together monoga­mously and asked half of them to write about feelings of love for their partner and the other half to write about a happy experience. Those who wrote about love actually turned their attention away from attractive members of the opposite sex even more quickly than they looked away from average-looking people. Subjects who wrote about being happy, however, remained as distracted by a pretty face as ever.

This unconscious attentional bias probably evolved to help men and women stay in monogamous relation­ships, which in humans tend to have a reproductive advantage, Maner explains: “This whole research area is guided largely by an evolutionary perspective. These biases have been built into our psychology to enhance people’s reproductive success.”

Note: This article was originally printed with the title, "See No Beauty".

If your institution has site license access, enter here.