Whether a married couple stay together has less to do with good chemistry than it does with solid mathematics, a new study says.
The paper, released yesterday at a conference in Scotland, represents another salvo in a continuing debate among psychologists about whether the strengths and flaws in human relationships can be accurately analyzed with formulas.
A prominent group of researchers argues that a new branch of math called non-linear dynamic modelling -- the same kind of chaos theory that figured out how a butterfly's movements can affect weather patterns -- can predict whether a married couple will divorce.
A distinguished member of that group, James Murray, a mathematician from the University of Washington, told the Mathematical Biology Conference at Dundee University that his calculations, based on two short equations, have correctly estimated how long a couple will remain married in 94 per cent of his test cases.
The study began a decade ago in Seattle, where Prof. Murray and psychologist John Gottman examined 700 couples who were planning to get married or had recently wed. While the couples talked with each other for 15 minutes, every piece of their conversation was given a score. Jokes, smiles and affectionate gestures earned points; rolled eyes, criticism, and mocking subtracted them.
Those numbers were then analyzed using Prof. Murray's formulas.
"Against time evolution, we can work out if they are likely to stay together or if they are more likely to divorce," Prof. Murray told British Broadcasting Corp. News. "Math provides a language for interpreting the human interaction. It quantifies one person's effect on the other, and it is not difficult."
It's the largest in a series of similar studies that the Seattle researchers have been publishing since the late 1990s, and the results have divided psychologists and therapists.
Some say it's revolutionary, while others contend that humans are too complex for such formulas to ever become a useful counselling tool.
"I buy it," said Sheldon Walker, a Calgary-based psychologist and family therapist, citing the prominent status of Dr. Gottman, the lead psychologist on the project. "I follow John Gottman's marriage counselling to the letter."
" 'Amazing' is an understatement," said Bernard Guerney, director and founder of the National Institute of Relationship Enhancement in Bethesda, Md. "The implications are enormous."
Governments should consider making this kind of test mandatory before granting marriage licenses, Dr. Guerney said, as a way of mitigating the high economic and social costs of divorce.
"You could almost make a case for requiring this kind of test before you allow people to get married," he said. "I would vote for something like that."
But others contend that the formulas have never been field-tested, suggesting that the studies so far lack validity because the couples involved volunteered to be analyzed.
"He has never, ever taken this out of the lab and been able to predict what will happen in a real population," said Diane Sollee, founder of the Coalition for Marriage, Family and Couples Education in Washington, D.C.
Ms. Sollee said other psychologists have also complained the tests look only at a couple's communication skills, and ignore other factors that affect divorce rates.
Formula for divorce
Wife's equation:
Wt+1 = a + r1 Wt + IHW (Ht)
W = wife, H = husband, t = time a = a constant representing the wife's state of mind when she is not with her husband. R1Wt = represents how easy it is to change her state of mind when she is in conversation with her husband. IHW = "influence function" - a measure of the influence that a husband's remarks have on his wife. Ht = the husband's score during their 15-minute conversation. Wt+I = how the wife has reacted to her husband's conversation - the higher the number, the greater the likelihood of divorce.
Husband's equation:
Ht+1 = b + r2Ht + IWH (W1)
b = a constant representing the husband's state of mind when he is not with his wife: r2Wt = represents how easy it is for him to change his state of mind when he is in conversation with his wife. IWH = "influence function" - a measure of the influence that a wife's remarks have on her husband. Wt = the wife's score during their 15-minute conversation. Ht+I = how the husband has reacted to his wife's conversation - the higher the number, the greater the likelihood of divorce.
Source: JOURNAL OF FAMILY PSYCHOLOGY, 1995