Lots of things out there come with a 50% chance of occurring—a coin toss coming up heads, of course; having one shared birthday among 25 people at a party; being born with webbed toes if a parent and grandparent have them; running out of money by 30 years after retirement with a typical financial portfolio; and, according to many studies over recent decades, having a marriage end in divorce.
That last factoid, along with the incidence of marriages that stay intact but founder, is a doozy. So it isn't surprising that lots of science and pseudoscience has gone into identifying predictors of successful marriages.
Scientists have used brain scanners to peek inside people's heads while they think about their spouses. Others ask couples to discuss one of their relationship's contentious issues and collect data about body language during the ensuing argument. And then there are the Harvard mathematicians who report an enormous likelihood that a marriage will succeed if a couple gives the same answers to just three questions: "Do you like horror movies?" "Have you ever traveled around another country alone?" and "Wouldn't it be fun to chuck it all and go live on a sailboat?"
An excellent 2013 paper in the journal Science adds important insights to the matter.
The research, led by James McNulty of Florida State University, involved members of 135 newlywed couples who answered a standard survey about the quality of their marriages. The scientists intermittently collected similar data from them over the next four years.
First off, they found that ratings of marital satisfaction declined over time, something reported previously. They also learned that the answers from newlyweds predicted nothing about marital satisfaction four years later.
But the scientists also measured something else in those newlyweds, using an "associative priming task."
This involves briefly flashing a series of words like "wonderful" or "odious" on a screen; subjects have to quickly press one of two buttons, depending on whether the word has positive or negative connotations.
Now comes the subconscious manipulation.
Just before each word, the researchers flashed up a picture of a random face for an instant—300 milliseconds—too fast for people to be consciously certain about what they saw but enough time for our subconscious, emotional brain circuitry to be certain. If the face evokes positive feelings, the brain immediately takes on something akin to a positive mind-set; if the word flashed up an instant later is a positive one, the brain quickly detects it as such. But if the word is negative, there is an instant of subconscious dissonance—"I was feeling great, but now I have to think about that word that means 'inconsiderate jerk who doesn't replace the toilet paper.' " And it takes a few milliseconds longer to hit the "negative" key. Conversely, display faces with negative connotations, and there is that dissonance-induced minuscule delay in identifying positive terms.
So in the study, the rapid-fire sequence of faces/words included a picture of one's new spouse, revealing automatic feelings about the person's beloved. That led to the key finding: The more subconscious negativity in a newlywed, the larger the decline in marital satisfaction four years later.
Did subjects understand what the priming task was about? No, and people's automatic responses were unrelated to their answers on the questionnaire. Was that discrepancy due to an unwillingness to answer honestly, or were people unaware of their automatic attitudes? It is impossible to tell. Did people with the most positive automatic feelings about their spouses subsequently develop fewer problems in their marriages, or were they less sensitive to the usual number of problems? Subtle data analysis suggested the latter.
What does this study tell us, beyond suggesting that lovebirds should probably take this nifty computerized test before marrying? It reminds us, like much we learn about the brain and behavior, that we are subject to endless, internal biological forces of which we are unaware.