It might not sound romantic, but Helen Fisher has love down to a science.

Fisher is a biological anthropologist and a scientific advisor to Match.com. She and her fellow researchers have spent a lot of time using MRI scanners to look at the brains of people in love.

While all of Fisher’s work is fascinating, her findings about people in long-term relationships who report that they’re still in love are especially intriguing. We usually think of new love as the most exciting and swoon-worthy. But the brains of Fisher’s subjects — mostly n their 50’s and married an average of 21 years— clearly showed their passion still burning.

“Psychologists maintain that the dizzying feeling of intense romantic love lasts only about 18 months to—at best—three years. Yet the brains of these middle-aged men and women showed much the same activity as those of young lovers, individuals who had been intensely in love an average of only seven months,” Fisher writes in O Magazine.

What’s keeping their love alive? And what can the rest of us learn from Fisher’s findings?

Does Your Brain Wear Rose-Colored Glasses?

Because our brains are wired to keep us alive, we naturally tend to look for the negative in order to quickly spot anything potentially risky or dangerous. Unfortunately, this thinking bias can cause problems in our relationships if we’re not careful.

Fisher found that longtime lovers have reduced activity in the part of the brain that skews negative, which suggests that they’ve honed their ability to see the positives in their partner.

“Men and women who continue to maintain that their partner is attractive, funny, kind and ideal for them in just about every way remain content with each other,” Fisher writes. “Perhaps this form of self-deception is a gift from nature, enabling us to triumph over the rough spots and the changes in our relationships.”

Does your brain need some training to accentuate the positive? Make an extra effort to notice the good things that your husband does and to remind yourself of all the reasons you fell in love with him in the first place.

(A quick note here: In no way is Fisher suggesting that you overlook serious issues, like abuse.)

How Active Are Your Mirror Neurons?

Another interesting thing about the brains of Fisher’s subjects was the higher activity of the mirror neurons which are nerve cells linked with empathy. That’s not surprising. We all long to feel heard and understood in our relationships.

Unfortunately, life gets so busy and draining sometimes that it depletes our ability to be empathic with others. To improve your ability to put yourself in your partner’s shoes, there are a couple of exercises you can try. First, there’s the “marriage hack” that takes only 21 minutes per year. You can also work through the 36 questions that build closeness (which you may have seen featured in The New York Times).

Are You Caring For Yourself?

Finally, Fisher’s subjects showed notable activity in the brain regions associated with controlling emotions. Again, this makes a lot of sense. As I’ve written before, respect is the often-overlooked ingredient in lasting love. And it’s a lot easier to be respectful with your partner when your emotions don’t feel out of control.

If you do lash out at your husband frequently, take a look at the rest of your life. I’m betting that you’re pushing yourself hard and may not even realize the pressures you face. To get a better handle on your emotions, look at the factors that put you at risk for “flipping your lid” and engage in more self-care. As women, we’re often taught that tending to our own needs is selfish. But the truth is we can’t be there for others with love and respect if we don’t care for ourselves.

Be sure to take a few minutes to watch Fisher’s full TED Talk. I think you’ll come away with a fresh appreciation of the power and wonder of love. And for a guide to writing your own lasting love story, pick up a copy of my book Strong Women, Strong Love