As if inspiring countless songs and poems and an international holiday weren't enough, love now is being credited with a truly amazing power: the ability to resist temptation.
In an experiment with college students in long-term relationships, researchers at UCLA and the online dating service eHarmony found that asking coeds to reflect on the love they felt for their boyfriends or girlfriends blunted the appeal of especially attractive members of the opposite sex.
"Feeling love for your romantic partner appears to make everybody else less attractive, and the emotion appears to work in very specific ways by in enabling you to push thoughts of that tempting other out of your mind," said Gian Gonzaga, an eHarmony research scientist and lead author of the study, which appears in the current issue of the journal Evolution and Human Behavior.
"It's almost like love puts blinders on people," said co-author Martie Haselton, an associate professor of psychology and communication studies at UCLA.
With their research, Gonzaga and Haselton believe they have glimpsed the biological imperative behind the emotion that makes people feel all gushy and do silly things.
"Popular culture may mix romantic love up with sexual desire, but from an evolutionary perspective, romantic love fulfills a different function," Haselton said. "Love is a commitment device, which has evolved to make us identify and stick with a long-term mate long enough to raise a child. Our ancestors who had this ability were more successful in raising their offspring to maturity, so the adaptation got passed along to us."
The researchers invited 120 heterosexual undergraduates in committed relationships to pore over photographs of attractive members of the opposite sex.
"We got the photos from Hot or Not," Haselton said, referring to the popular dating Web site, "and we only downloaded the hot ones."
From the dozens of photos at their disposal, the undergrads were asked to identify the member of the opposite sex to whom they felt most physically attracted.
The researchers then asked each undergraduate to compose an essay on one of three subjects: the time they felt the most love for their current romantic partner, the time they felt the most sexual desire for their current romantic partner, or anything they wanted to write about. The third group acted as a control group.
"Basically, these students were reliving an intense moment of love or an intense moment of sexual desire for their partner," said Gonzaga, who oversees an observational laboratory at eHarmony's Pasadena headquarters that conducts research in interpersonal chemistry and long-term relationship building.
While writing, the undergraduates were instructed to put the attractive other out of their mind. If they nevertheless happened to think of the hottie, they were asked to put a check in the margin of their essays every time they did so. Later, they were asked to list the hottie's attributes.
Undergraduates who reflected on the love they felt for their romantic partner were six times less likely than the control group, and more than four times less likely than the group that wrote about their sexual desire for their partner, to think of the hottie. On average, undergraduates in the love group thought of the tempting other once every two pages, compared with more than twice a page for the desire group and almost four times a page for the control group.
"People in the love group found it easy to push an attractive other out of their mind even though we made those thoughts tempting," said Haselton, who is affiliated with UCLA's Center for Behavior, Evolution and Culture.
In fact, conventional wisdom holds that when people are instructed to not think of something, a "rebound effect" occurs, causing the taboo thought to present itself even more frequently than it otherwise would.
Not only were the undergraduates in the love group less likely to think of the attractive others, but they had a much tougher time later recalling the hottie's appeal. On average, students from the love group remembered about two-thirds as many attractive features — such as bulging muscles or a low-cut blouse — as the students in the desire and control groups. And what members of the love group did remember of the hotties was less likely to be an attractive feature than a sort of general, identifying characteristic like the location where the photo was shot or the color of an article of the hottie's clothing.
"These people could remember the color 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."
The findings are consistent with past research, which has shown that people in romantic relationships rate potential others as less attractive than their uncommitted counterparts. Research has also shown that when shown photos of attractive members of the opposite sex, people in romantic relationships tend to spend less time looking at the photos than noncommitted people.
"Earlier studies didn't examine whether love was driving the pattern," Haselton said. "It could be that people who end up in relationships might be the people who don't look at others. This is the first direct causal evidence between feeling love and defending a relationship from external threats."
Overall, reliving a loving moment with a romantic partner helped blunt the allure of a potential threat to the relationship.
"One of the biggest threats to a relationship is an attractive alternative to your loved one — or that attractive woman at work or the hot guy you meet in the bar," Gonzaga said. "In subtle ways that you might not even notice, the gushy feelings you get when you think of your partner help you fend off these threats."
Backed by 35 years of clinical and empirical research, eHarmony is one of the most popular online relationship services and is dedicated to building the relationships of both singles and married couples. The company was founded by relationship expert, best-selling author and clinical psychologist Dr. Neil Clark Warren.
Source: UCLA, By Meg Sullivan
Explore further: No, opposites do not attract