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Robert P. Burriss Ph.D.

The Danger of a Wandering Eye

A long-term study of newlyweds reveals the precursors of infidelity.

Infidelity is a major cause of relationship breakdown, and so understanding why some people cheat is an important area of research.

Of course, none of us is immune to temptation. Committing to a long-term, exclusive relationship doesn’t close our minds to the alternative. A marriage vow enshrines our intention “to forsake all others,” but it can’t render all others unattractive.

Psychological research suggests that we manage our illicit desires by tearing our attentions away from appealing alternatives (“Out of sight, out of mind”), and by devaluing the allure of those who nevertheless catch our eye ("They aren’t all that”). Those who report greater commitment to their partners tend to deploy these so-called “evaluative biases” more effectively.

James McNulty and his colleagues at Florida State University, in a paper published recently in the Journal of Personality and Social Psychology, wondered whether evaluative biases have any effect on real-world behavior. Reported feelings of commitment are one thing, but actual infidelity is another thing entirely.

Are people who are able to still their wandering eyes less likely to cheat?

McNulty’s team recruited around 500 newlyweds (most couples were male-female) for a long-term study. At the beginning of the study, all the volunteers visited the researchers’ lab. There they completed two tasks:

  • The first was a test of the volunteers’ attention to romantic alternatives. The volunteers were shown a series of photographs of attractive and average-looking men and women on a computer screen. After each photograph disappeared from the screen, it was replaced by a square or a circle. The volunteers’ job was to click one button if the shape was a square and another if it was a circle. Sounds easy, right? However, the photograph wasn’t always in the same place on the screen —each one jumped to a new position. And the shapes that appeared after the photographs were sometimes in the same position as the photograph, and sometimes elsewhere. The idea behind the task was that volunteers who find it difficult to drag their attention away from a face will be slower to categorize a shape when it materializes elsewhere on the screen. An attractive face is more likely to "glue" your eyes in position.
  • In the second task, the volunteers’ tendency to devalue the attractiveness of others was tested. The volunteers rated the attractiveness of the same men and women whose photographs they had seen in the first task. A control group of single volunteers also rated the photographs. On average, the newlyweds rated the photographs as less attractive than the singletons did, which confirms the results of previous research indicating that those in a committed relationship are more inclined to devalue the attractiveness of others. However, each volunteer varied in the extent to which they devalued attractiveness compared to the average singleton. Some thought the faces were relatively unattractive; others thought the faces were relatively attractive.

Over the next three years, the volunteers periodically completed surveys about their commitment to their marriage, and reported on infidelity by themselves and their spouses.

McNulty discovered that those who had found attractive others more attention-grabbing were more likely to have cheated on their partner by the end of the three years. In fact, he could be specific about it: Each increase in the speed of disengagement of one-tenth of a second (about the difference between gold and silver medal times in elite 100m sprint races) decreased the odds of infidelity by a massive 50 percent. I’ll say it again: If you can tear your eyes away from a hottie 100ms faster, you are half as likely to cheat on your partner in the next three years.

Source: Elnur/Shutterstock

Of course, we can’t be sure that cheating is caused by a wandering eye. It is possible that people who are distracted by attractive alternatives also behave differently in other ways, or possess certain attitudes or values that directly influence infidelity. McNulty also found that cheaters were more likely to report lower relationship satisfaction and to have younger partners.

Those who reported infidelity were also less likely to devalue the attractiveness of alternatives: If you think other people are hot, you’re more likely to stray. In McNulty’s study, volunteers who rated attractive, opposite-sex persons an average of two points lower in attractiveness on a 1–10 scale were half as likely to have cheated.

So, a tendency to avoid looking at attractive others, and to view those who do attract attention as less appealing, does seem to be associated with faithfulness.

Further analyses revealed that people who rated others as more attractive tended to be less satisfied with their relationships by the end of the three years. Also, McNulty discovered that volunteers who found it more difficult to drag their attention away from attractive alternatives were more likely to have broken up. (After three years, around 12 percent of all the couples had gone their separate ways.)

Volunteers were also photographed at the beginning of the study, and their own photographs were rated for attractiveness by a group of independent volunteers. When a woman was low in others' perceived attractiveness, both she and her partner were more likely to cheat. The male partner’s attractiveness was unimportant.


McNulty, J. K., Meltzer, A. L., Makhanova, A., & Maner, J. K. (in press). Attentional and evaluative biases help people maintain relationships by avoiding infidelity. Journal of Personality and Social Psychology. doi:10.1037/pspi0000127