The mathematical marriage predictor.

You might not think that mathematicians have anything particularly relevant to say about your love life. But you'd be wrong--if we're talking about James Murray, a mathematician at the University of Washington in Seattle who teamed up with Psychologist John Gottman to explore the rocky road of romance. Here's what the two did. They videotaped hundreds of volunteer couples discussing such things as sex and money. You know--the sorts of things on which everybody always agrees, right?

Then they broke down behavioral responses to these high-pressure discussions into recognizable groups, such as whether partner A can be persuaded by partner B, or whether partner A takes offense when partner B makes a cutting remark. A set of equations was drawn up that represented the interactions of these different factors in mathematical form, leading to...Ding!...a prediction as to whether this marriage would last.

Sound like a stretch? Think you can't possibly tell that much about a couple from a single interview and some calculations? Four years later Murray and Gottman did a follow-up to see whether the equation had made the right prediction. It sure had--their Mathematical Marriage Predictor was right an astonishing ninety-four percent of the time.

Some conspicuous findings included the fact that, in marriages that lasted, laughing occurred five times more frequently than in couples destined for break-up. The team also found that the one behavior that most consistently predicted divorce was the appearance of a contemptuous or mocking facial expression on one partner's face when the other one spoke. According to the Mathematical Marriage Predictor, it's "roll your eyes and say goodbyes."