Mathematician predicts divorce by the numbers

Is it breakfast in bed, romance or companionship that makes a good marriage?

It’s all in the numbers, claims one determined mathematician who has developed an algebraic formula that predicts the longevity of marital bliss — with a 94 percent success rate.

James Murray, a professor of mathematical biology at the University of Washington, studied 700 couples for a decade before arriving at his equation, which was presented Thursday before an international mathematical biology conference in Scotland.

The experimental field uses computer models and mathematical sequences to predict cell growth, molecular formations, disease progressions, animal markings and other medical or biological phenomenon.

Mr. Murray, who has been married for 40 years, is one of the few who has applied the science to the tempestuous, heretofore unpredictable domain of couplehood.

“Modeling marital interaction,” he believes, “has turned out to be surprisingly accurate in its predictions … in a large sample of marriages in Washington state, our prediction as to which couples would divorce within a four-year period was 94 percent accurate.”

Mr. Murray has gotten it all down, literally, to a science and a protocol.

The test couple in question only need to talk to one another for 15 minutes. But they won’t be talking about the weather.

Husbands and wives are asked to discuss things that often wreak havoc in a relationship: sex, money, child-rearing or other troublesome topics. The civility of the spouses is then analyzed on a numerical scale, their points and counterpoints assigned anything between the dreaded minus four and the happy-go-lucky plus four.

Is the husband being a critical cad or the wife a manipulative brat? Both get a minus four. Do they jolly one another out of an argument with humor? They receive a plus two.

Scorn in any form warrants a minus three.

“Math provides a language for interpreting the human interaction. It quantifies one person’s effect on the other, and it is not difficult,” Mr. Murray told the conference.

The formula, for the untrained eye anyway, is an intimidating parade of w’s, h’s, parentheses and brackets. Mr. Murray insists it’s all done at high school algebra level.

The numerical quotients from the test conversation are plugged into separate equations for both husband and wife, combined with figures representing each spouse’s mood and the all important “influence function.”

That figure represents how much sway the respective partner holds over the other.

When calculations are complete, the higher the final number in the equation, the more likely a couple is to divorce.

In Mr. Murray’s experiments, which began in 1992, couples were tracked and rated every two years with the help of John Gottman, a professor of psychology at the University of Washington.

The pair produced an academic book earlier last year about their research called “The Mathematics of Marriage: Dynamic, Nonlinear Models,” which explores the parameters of such things as the “screaming-and-throwing-plates marriage,” or the catastrophic collapse of the doomed relationship.

Typically, marriage counselors gauge the quality of their charges’ relationships with complex sets of questions.

Psychologist Gottman himself runs the “Love Lab” — a physiology laboratory where couples are screened, interviewed, observed, videotaped and hooked up to monitors that measure pulse and “jitteriness and skin conductivity,” among other things.

Mr. Gottman’s own quiz — “How well do you know your partner?” — is available at his Web site (www.gottman.com).

It’s all part of developing one’s “love map,” he notes.

Mr. Murray, however, is convinced that scientific discipline is the key, and envisions couples taking his conversation test when they apply for a marriage license.

Would couples be told they were incompatible on the spot?

No. The calculations, he said, could help suggest “specific marital therapy” in the future.

The procedure, he said, is already being used “with encouraging results.”