Here’s the No. 1 phrase used in successful relationships, say psychologists who studied 40,000 couples (2024)

For the past 50 years, we've been putting love under the microscope.

As psychologists, we'vestudiedmore than 40,000 partners about to begin couples therapy. We've also been happily married to each other for 35 years, so we know a thing or two about successful relationships.

While every partnership is unique, with its own set of challenges, there's one thing that all couples have in common: We want to be appreciated. To be acknowledged for our efforts. We want to be seen.

A thriving relationship requires an enthusiastic culture of appreciation, where we're as good at noticing the things our partners are doing right as we are at noticing what they're doing wrong.

But it's easy to fall into the trap of only seeing what your partner is not doing. You develop a narrative where you're the one putting in all the effort, and you start to believe it's true.

Getting rid of this toxic mindset requires building a new one: scanning for the positives and saying "thank you."

You probably say "thank you" all day long, almost without thinking, to your colleagues, to the bagger at the supermarket, or to the stranger who holds the door for you.

But in our most intimate relationships, we can forget how important saying "thank you" really is.

For many of the couples we've worked with, we found that when one person started the cycle of appreciation, it became easy for the other to join in and strengthen it.

Here's your assignment for today:

Step 1: Be an anthropologist.

Keep a close eye on your partner, whenever you can. Follow them around. Write down what they do, especially the positive stuff! Don't write down the negatives, such as ignoring a pile of papers you asked them to pick up.

Note that they washed the breakfast dishes, fielded phone calls, picked up the toys strewn all over the living room, and made you coffee when they went to make one for themselves.

You don't have to hide the fact that you're spying. You can tell your partner you're observing them to get a better sense of their day, and everything they do.

Their behavior isn't going to change much just by knowing you're watching.

Step 2: Say "thank you."

Thank them for something routine that they're doing right, even if it's small, even if they do it every day — in fact, especially if it's small and they do it every day!

But don't just say "Hey, thanks." Tell them why that small thing is a big deal to you: "Thank you for making the coffee every morning. I love waking up to the smell of it and the sounds of you in the kitchen. It just makes me start the day off right."

Don't expect this to be easy. You may run into some challenges. Here's our best advice:

If you're crunched for time...

Make a quick list of everything you each do, then pick a couple of things to flip-flop on. If you're always the one who gets the kids off to school, have your partner do it today instead. If your partner is always the one to make dinner, you do it tonight.

See what it feels like to put yourself in each other's shoes.

If you're having trouble getting out of the negative perspective...

Try to separate the negative feelings about what happened in the past. Focus on the here and now, this specific moment, this specific person. What can you tangibly observe?

Ask yourself: "Have I had these negative feelings before this relationship ever began? Who with? What set off those feelings?"

Identifying, naming and sourcing these types of negative thoughts and feelings can help you let them go.

If it feels like you're seeing the positives, but your partner is not...

Remember, you're trying to change your own mental habits. You're not changing your partner.

Ultimately, how they think and feel is not within your control. But changing your own way of looking at the world is powerful. You're disrupting the cycle of negativity and refusing to give it any fuel to continue. And that alone can make a significant difference.

Dr. John Gottman and Dr. Julie Schwartz Gottmanare the co-founders ofThe Gottman InstituteandLove Lab. Married for over 35 years, the two psychologists are world-renowned for their work on relationship stability and divorce prediction. They are also the co-authors of"The Love Prescription: Seven Days to More Intimacy, Connection, and Joy"and"10 Principles for Doing Effective Couples Therapy."Follow them onInstagramandTwitter.

Don't miss:

• Here's the No. 1 thing that makes relationships successful, say psychologists who studied 40,000 couples
• 'Yes, marry for money': A top economist shares the surprising financial benefits of marriage
• I'm a psychology expert in Finland, the No. 1 happiest country in the world—here are 3 things we never do

Sign up now: Get smarter about your money and career with our weekly newsletter