Picture a couple heading out the door after dinner for a walk around the block. Nothing dramatic, just twenty minutes, side by side, talking about the day. A new study says couples like that tend to have stronger marriages. It is the kind of finding that makes for a warm headline: one simple habit, a better relationship. I like the study. I also think it is a perfect teaching moment, because the headline quietly makes a promise the research cannot keep.
Let me tell you what the researchers found, and then let me show you why a good skeptic, which is what I want my students to become, should pump the brakes.
What the study found
Researchers at Brigham Young University looked at roughly 1,700 married couples who are part of the CREATE study, a project that has followed married couples across the United States for more than a decade. They compared how much each spouse exercised, alone and together, against three things: how well the couple communicated, how they handled conflict, and how much marital stress they felt.
Exercise in general went along with healthier relationships. The pattern was stronger when the two people worked out together, and walking was the most common shared activity. About 60 percent of people in the sample exercised, but only about a third did so with their spouse. The authors are careful, and I want to be too: they describe an association, not a cause, and they call the effect modest.
The trap in the headline
Here is the idea I want you to walk away with. When a study reports that people who do X also tend to have Y, it is tempting to read that as X causes Y. That is a causal claim, and this study cannot support it. What it found is a correlation, a tendency for two things to show up together. Correlation tells you the two travel as a pair. It does not tell you which one is in the driver’s seat.
So let us lay out the possibilities, because there are at least three, and the data cannot pick between them.
The first is the one the headline wants: walking together improves the marriage. Shared time, easy conversation, a small daily dose of teamwork.
The second runs the other direction, and I think it is at least as believable. A good marriage produces the walking. Couples who already enjoy each other look for reasons to spend time together, so the closeness comes first and the evening walk is the result, not the cause. Psychologists call this reverse causation, and it is the explanation people forget most often.
The third is the sneaky one: some other factor feeds both. Think about what it takes to walk together most evenings. Two people healthy enough to walk. Schedules that overlap, so no opposite shifts and no newborn keeping everyone up. A certain amount of follow-through. A safe, walkable street. Less money stress. Any of these could lift both the exercise and the marriage on its own, while the walking does little of the real work. A hidden factor like this is called a third variable, or a confound, and it is the reason researchers lose sleep.
How would we actually know?
If you want to know whether the walking is doing the work, you need a different kind of study. The gold standard is the randomized controlled trial: take a group of couples, randomly assign some to a shared activity and some to a waitlist, then see what happens. Random assignment is the magic, because it scrambles all those third variables evenly across both groups, so if the activity group pulls ahead, the activity is the likely reason. We have a clean example from another corner of psychology: a recent trial randomly assigned young adults with depression to eight weeks of salsa classes or a waitlist, and the dancers improved. Because of the random assignment, that study can say the classes helped. The marriage study, built on a snapshot of who happens to walk together, cannot.
The part that surprises people
Now here is where I get to play both sides, which is the fun of this. Shared activity is not only correlational folklore. There is real experimental evidence that doing things together can cause a relationship to improve, and it comes from the self-expansion model of Arthur Aron and his colleagues. The idea is that we are drawn to relationships that grow us, that add new experiences and abilities, and that fresh shared activities keep that growth going.
Aron’s team tested it the right way. In one study, they randomly assigned married couples to spend about ninety minutes a week on activities that were novel and a little exciting, or on activities that were pleasant but ordinary, or on nothing special. Over ten weeks, the couples in the novel and exciting group reported the biggest gains in marital satisfaction. In the lab they went further: couples randomly assigned to a slightly challenging joint task, crawling across mats while tied together at the wrist and ankle, came out reporting warmer feelings about their relationship than couples given a dull task. Same partners, different assigned activity, different result. That is a causal claim earned honestly.
But notice the active ingredient. It was novelty and a bit of arousal, not movement by itself. A calm nightly walk is pleasant, and pleasant is good, yet it is not especially novel or exciting. So the mechanism that powered Aron’s results may not be the one behind the walking study. That is worth sitting with, rather than smoothing over.
And more is not always better. A separate long-term study with the playful title “Do couples who play together stay together?” found that shared leisure helped higher-income couples but could add strain for lower-income couples, where time and money are tighter. “Do more together” is good advice for some couples and the wrong advice for others.
If walking together does help, why might it?
Suppose there is a real, if modest, effect. A few mechanisms are worth naming, as hypotheses rather than settled facts. Walking puts two people shoulder to shoulder instead of face to face, which tends to take the heat out of hard conversations, and the study’s strongest links were to communication and conflict. Moving in step also matters: when people fall into the same rhythm, a pattern psychologists call behavioral synchrony, they tend to like and cooperate with each other more. Exercise lifts mood on its own, and a calmer, happier person is simply an easier partner to live with. There is even a playful possibility from an old classic, the misattribution of arousal, where the racing heart from exertion gets read as feelings about the person you are with, the same quirk behind the famous shaky-bridge study from the 1970s.
The honest takeaway
My best read is that the arrow points both ways, and gently. A good marriage probably invites more shared walks, and shared walks probably give a little back. Walking together costs nothing, feels good, and is very unlikely to hurt, so it is a reasonable bet even without proof that it causes closeness. But the headline sells a correlation as a cure, and the habit I most want you to build is the one that kicks in every time you see “one simple habit for a better anything.” Ask two questions: compared to what, and how do they know which way the arrow points? Do that, and you are thinking like a psychologist.
References
Mildenhall, A., Nunez, M. L., & Yorgason, J. (2026). Physical activity and marital quality. Family Relations. https://doi.org/10.1111/fare.70260
Secondary coverage I drew on for the summary: ScienceDaily and SciTechDaily, and the BYU News write-up.
Aron, A., Norman, C. C., Aron, E. N., McKenna, C., & Heyman, R. E. (2000). Couples’ shared participation in novel and arousing activities and experienced relationship quality. Journal of Personality and Social Psychology, 78(2), 273-284. https://doi.org/10.1037/0022-3514.78.2.273
Reissman, C., Aron, A., & Bergen, M. R. (1993). Shared activities and marital satisfaction: Causal direction and self-expansion versus boredom. Journal of Social and Personal Relationships, 10(2), 243-254. https://doi.org/10.1177/026540759301000205
Totenhagen, C. J., Li, X., Wilmarth, M. J., Archuleta, K. L., & Yorgason, J. (2023). Do couples who play together stay together? Family Process. https://doi.org/10.1111/famp.12869
Dutton, D. G., & Aron, A. P. (1974). Some evidence for heightened sexual attraction under conditions of high anxiety. Journal of Personality and Social Psychology, 30(4), 510-517. https://doi.org/10.1037/h0037031