A simple “thank you,” can go a long way. It goes even further when it’s unexpected — when you show a little appreciation without prompting.

And you know when a well-placed expression of gratitude is at it's most magical?

When you say it to your spouse, and when you hear it from your spouse, especially if you haven’t said or heard it in a while.

Which, odds are, you probably haven’t.

Those two little words, that simple articulation of appreciation, posing a tiny little question that indicates that you’re thinking of your significant other and all that she does for you ... those things can defuse an argument, make everybody involved feel a lot better and make you — you sweet-talking devil, you — look as strong to your spouse as you did the day you were married.

The power of gratitude is scientifically proven. Or, at least, scientifically strongly suggested. (Still need a nudge? Really?? The video below will push you in the right direction.)

Why 'thank you' matters

“The findings may not be major revelations,” says Allen Barton, the lead author of a recent paper on the subject, “but what it does show is that, 1), [Showing gratitude] matters. It has an impact in multiple areas of marital quality. And, 2), I don’t know if it's something that couples devote as much attention to as they may need to.”

Barton and University of Georgia colleagues Ted Furtis and Robert Nielsen surveyed 468 married folks and asked about their financial situations (often a source of marriage friction), how they communicate when there are problems and how they express thanks to their partners.

Allen Barton, UGA professorAllen Barton is the lead author on this particular paper and he's gotta ask: Have you said thanks to your spouse today? (Photo: /UGA)

They found that the most consistent, most significant predictor of marital satisfaction was the simple gratitude shown from one spouse to the other. In other words:

“Thanks for watching the kids last night and letting me go to the movies."

“Hon, I appreciate what you do around the house. I don’t think I tell you that enough."

“Sweetie, thanks for cleaning up the dog poop.”

“Baby, I know you hate that commute in the morning. Thanks for toughing it out.”

“Pumpkin pie, what do you say we go to dinner tonight to give you a break? You’ve been working so hard.”

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Think about it. Those kinds of things, said the right way (and, of course, with a little conviction), can go a long way toward making those other things you argue about seem a lot less important.

“Positive relationship outcomes appear to be associated not only with being appreciative and possessing gratitude for one’s partner ...,” the authors write, “but also as the current study highlights, feeling appreciated and perceiving gratitude from one’s partner.”

The study is called “Linking financial distress to marital quality: The intermediary roles of demand/withdraw and spousal gratitude expressions.” It was published in an October issue of the journal Personal Relationships.

What role do you play?

The study examined, as the title reveals, how couples deal with financial problems and a “demand/withdraw” way of communicating. That occurs when one spouse demands something and the other withdraws from the conversation. It’s obviously not a great way to hash things out.

But the researchers discovered that many couples can get past that, that they can stop that demand/withdraw cycle simply by passing on a little gratitude.

Makes you wonder why many of us don’t.

The UGA study didn’t delve into that. But a couple of possible reasons come to mind, Barton says.

The first: “Increasingly, people write about how we live with a kind of individualistic view of marriage,” says Barton. “‘Am I satisfied, am I getting what I want out of this relationship?’” That’s not conducive to a happy marriage, he says.

The second: The “I’m putting more into this than you are” way of thinking. Even if that’s flat-out wrong. “Typically,” Barton says, citing previous studies, “everyone overestimates the amount of work that they do, and underestimates the amount of work that their spouse does.”

The good news is, escaping that particular psychological marriage quagmire is not impossible.

It starts with an acknowledgement. And two simple words.