Newly-weds can now discover if they are destined for the divorce courts by applying a mathematical model that can predict whether their marriage will succeed.
A mathematician has devised two formulae that he claims have a 94 per cent success rate when it comes to forecasting whether a couple are compatible. The suggestion that the secret of a happy marriage can be found within two complex lines of algebra was made by Prof. James Murray of the University of Washington, Seattle.
The model was presented to an international conference for the first time yesterday when Prof. Murray addressed academics at the Mathematical Biology Conference at Dundee University.
The formulae were calculated during a 10-year study of 700 couples from King County, Seattle, conducted by Prof. Murray and his colleague John Gottman, a psychologist.
The experiment, which began in the early nineties, involved all the couples being observed during a 15-minute conversation when they were just married.
A contentious topic such as sex, child-rearing or money was chosen and the couple’s ability to communicate was marked using a scale that gave positive points for good signals and negative points for bad signals.
For example, jokes, a positive tone of voice, smiles and affectionate gestures all resulted in positive scores. Bad signals such as rolling of the eyes, criticism, mocking and coldness led to a negative score.
“We used an accepted psychological scoring system to award them points, such as minus three for scorn and plus two for humour,” said Prof. Murray, the author of Mathematics for Marriage.
“Then we put their points on a graph and by converting them into algebraic terms were able to make our divorce predictions. We didn’t tell the volunteers of course, as that could have defeated the object. And telling a couple their marriage is going to fail is not what they want to hear. But the success rate was amazing.”
The results were fed into two equations — one for the husband and one for the wife.
The equations were used to calculate the compatibility of the couples by adding a series of other variables such as an “influence function” that differed for each couple.
The “influence function” measured how much someone’s contribution to the conversation dictated the mood of his or her spouse.
The couples were tracked every two years and the model accurately predicted which marriages were doomed to failure in a country with a 50 per cent divorce rate.
Prof. Murray, an exiled Scot who has been happily married to his wife Sheila for 40 years, said: “I was absolutely astonished. The key thing that comes out of it is that we have been able to calculate how people interact. For example, the wife might be a conflict-avoider and the husband might be volatile. That marriage would not survive.
“But positive things can be taken from it. It points out why some people are having problems and can show what action has to be taken to save the marriage.”