The calculus of love - Mathematics - Brief Article

Science News, Feb 28, 2004

A mathematical model can predict whether a marriage will end in divorce, report researchers at the University of Washington in Seattle. Psychologist John Gottman tracked hundreds of couples as they discussed contentious issues such as sex and finances in videotaped 15-minute conversations. Together with mathematician James Murray and other colleagues, Gottman created a set of equations that takes into account partners' overall outlook on life, persuadability and the extent to which they let their significant other's compliments or snide digs affect them. The researchers interpreted the outputs of the equations as measures of matrimonial health.

Four years after the tapings, Murray and Gottman revisited the couples to see which marriages had lasted. They found that in 94 percent of cases, on the basis of a single interview, they had correctly predicted whether a couple was headed for "orgies of happiness or Calvinist hell," Murray reports.

In successful marriages, positive interactions such as laughing and joking during the taped interviews outnumbered negative ones by a 5-to-1 ratio. The best single predictor of divorce was a contemptuous facial expression by one partner as the other spoke--for instance, pursing one side of the mouth while rolling the eyes. "Contempt is the sulfuric acid of love" Gottman says.

The team is now using the model to tailor a couple's therapy--to determine whether the best way to save a particular marriage is, for instance, for the wife to let the husband's negative remarks roll off her back. In preliminary findings, about two-thirds of relationships improved after a few days of therapy guided by the equations, Gottman reports.--E.K.