For better or worse: marriage by the numbers

And it's what the numbers say about communication that's valuable. For instance, Gottman and Murray calculate the ratio of good versus bad signals couples send to each other when discussing an issue on which they disagree, such as money or child rearing. The good signals include positive tone of voice, smiles, jokes, any noticeable gesture of kindness or companionship. The bad ones include rolling of the eyes, criticism, mocking, perceptible coldness. According to Gottman, the couples who stay together send five times more affectionate signals than hostile ones. Those headed for breakup average closer to a 1-1 ratio.

Underlying these ratios are more fundamental communication styles. Men or women who have what Gottman calls a "validating," or highly sensitive, style are deeply stung when their partner is critical or cold, but quickly cheered by encouragement or good humor. So-called "volatile" individuals are not so easily moved by their partner's responses and moods; they can make a scene and then make up without being thrown much off their emotional center of gravity. On the other hand, "conflict avoiders" seem to respond only to positive cues, gestures and discussions, but tune out the dark notes altogether.

When both partners are of the same type, the relationship tends to be stable, the data suggest. That could help account for why couples who seem to be forever arguing often stay together, defying all appearances. It also accounts for those couples who thrive seemingly without ever confronting serious problems.

It's when two partners have different communication styles that their relationship is unstable, the researchers find. "This, I think, explains the phenomenon of what has been called the 'pursuer-distancer' relationship, in which one person wants to discuss change and the other person wants to flee the discussion at all costs," said Gottman.

Marriage researchers have long known that emotional mismatches can spell doom for a marriage. It's not that an explosive, emotionally intense wife cannot make herself understood to a reserved, distant husband; usually she can. It's that she misjudges the impact of her fits on him -- just as he misreads the effect of his silences on her. The result is that when discussing difficult topics neither person has a good sense of where the conversation is going or how to steer it emotionally. Gottman and Murray's calculations help quantify just how devastating this mismatch is, and for whom.