Does happy marriage cause happy marriage?

I don’t know how I missed this one, from two Valentine’s Days ago…

For an introductory methods course discussion on: when does something cause something else. Question: Are happier couples happier? Some writers think so:

• Washington Post: The Groupon effect: Can date-night deals save your marriage?
• Huffington Post: Date Nights: They Make Your Marriage Work
• Inquisitr: Date Nights Improve Marriage, Better Your Sex Life [Study]
• USA Today: ‘Date night’ can improve marriage, sexual satisfaction
• Cosmopolitan: Why Date Night Is So Important

I can see the study design now: a randomized group of couples were given coupons for date nights, and some time later were compared with a control group without the coupons. Or not. Cosmo summarized:

For their study, researchers from the University of Virginia’s National Marriage Project surveyed 1,600 couples and asked them about everything from relationship satisfaction to sex. They discovered that couples who spend at least one night a week alone together say they’re more committed to their relationship than those who don’t hang out together as much.

(The report, by Brad Wilcox and Jeffery Dew and posted online at the National Marriage Project, is here.)

BREAKING: Researchers discover murder less common among happy couples.

Is that it? A simple association between being together and being happy? Almost. First, they say (there are no tables) that they “control for factors such as income, age, education, race, and ethnicity.” Such as? Anyway.

Second, they also claim to have analyzed historical data from the National Survey of Families and Households (1987-1994). They write:

Because we had data from spouses at two time points in the NSFH, we were also able to examine the direction of effects—to determine whether or not couple time reported during the first wave of the survey was associated with marital quality at the second wave. Here, the more couple time individuals reported at the time of the first survey, the more likely they were to be very happy in their marriage at the second survey, five years later. Although the NSFH evidence does not provide us with definitive proof that couple time causes increases in marital quality, the longitudinal character of the data suggests that the relationship may indeed be causal.

So, Wilcox and Dew point #1: If something happened before something else, “the relationship may indeed be causal.” They go on:

It is certainly intuitively true that greater satisfaction with one’s partner should also lead to more time spent in positive, shared activities. Nevertheless, it would be absurd to assume that two partners who intentionally set out to increase positive couple time spent together would typically not benefit from such time with increases in connection and happiness.

So, point #2 is, We already knew the answer before we did the research, because it’s flipping obvious, so who cares about this analysis — it’s almost Valentine’s Day!

There are ways to actually get at “the direction of effects,” like the randomized trial I suggested, or even using longitudinal data and assessing changes in happiness, or controlling for happiness at time 1. Not this.

Anyway, can we think of examples of things that occur before other things without causing them? Here are a few off the top of my head:

• One sibling dies of a genetic disease now, and then the other one dies from the same disease later: Shocking new evidence that genetics works sideways!
• Someone has tennis elbow now, and is playing sports later: The surprising way that getting hurt makes you athletic!
• People who spend more money now have more money later: The more you spend, the more you save!
• And of course, people who have a lot of sex now are good looking later: Sex up your looks!

I’m open to suggestions for better examples.

Note: I guess in some social science neighborhoods it’s common to analyze the effects of extremely similar things on each other, like pleasure being associated with happiness, or strong left arms being associated with strong right legs. Dew and Wilcox actually published a peer-reviewed article, using this survey, on the association between small acts of kindness in marriage and marital satisfaction. And the result? Couples who are nice to each other are happier.