The sudden breakup of Al and Tipper Gore’s seemingly idyllic marriage was the latest and among the sharpest reminders that the only two people who know what’s going on in a marriage are the two people who are in it.

Several years ago, a marriage researcher - Robert W. Levenson, director of the psychophysiology laboratory at the University of California, Berkeley - and his colleagues produced a video of 10 couples talking and bickering. Dr. Levenson knew at the time that five of the couples had been in troubled relationships and eventually divorced. He showed the video to 200 people, including pastors, marriage therapists and relationship scientists, asking them to spot the doomed marriages. They guessed wrong half the time.

“People on the outside aren’t very good at telling how marriages are really working,” he said.

Even so, academic researchers have become increasingly fascinated with long-married couples, subjecting them to tests and even brain scans to unravel the mystery of lasting love.

Bianca Acevedo, a postdoctoral researcher at the University of California, Santa Barbara, began a search for long-married couples who were still madly in love. Through a phone survey, she collected data on 274 men and women in committed relationships . To her surprise, Dr. Acevedo found about 40 percent of them continued to register high on the romance scale. The remaining 60 percent weren’t necessarily unhappy. Many had high levels of relationship satisfaction and were still in love, just not so intensely.

In a separate study, 17 men and women who were passionately in love agreed to undergo scans to determine what lasting romantic love looks like in the brain. The subjects, who had been married an average of about 21 years, viewed a picture of their spouse. As a control, they also viewed photos of two friends.

Compared with the reaction when looking at others, seeing the spouse activated parts of the brain associated with romantic love, much as it did when couples who had just fallen in love took the same test. But in the older couples, researchers spotted parts that the brain associated with deep attachment were also activated, suggesting that contentment in marriage and passion in marriage aren’t mutually exclusive.

“They have the feelings of euphoria, but also the feelings of calm and security that we feel when we’re attached to somebody,” Dr. Acevedo said. “I think it’s wonderful news.”

Beyond the brain scans, these couples remained active in each other’s lives. “They were still very much in love and engaged in the relationship,” Dr. Acevedo said. “That’s something that seems different from the Gores, who said they had grown apart.”

Indeed, if there is a lesson from the Gore breakup, it’s that with marriage, you’re never done working on it.


By TARA PARKER-POPE