The math of successful long-term relationships

José-Manuel Rey of the Department of Economic Analysis, at the Universidad Complutense in Madrid, has developed a clever mathematical model to examine "rising rates of marital breakdown", and arrived at a non-startling revelation: that effort is needed to maintain a successful long-term relationship.

The results of the mathematical analysis showed when both members of union are similar emotionally they have an “optimal effort policy,” which results in a happy, long-lasting relationship. The policy can break down if there is a tendency to reduce the effort because maintaining it causes discomfort, or because a lower degree of effort results in instability. Paradoxically, according to the second law model, a union everyone hopes will last forever is likely break up, a feature Rey calls the “failure paradox”.

According to the model, successful long-term relationships are those with the most tolerable gap between the amount of effort that would be regarded by the couple as optimal and the effort actually required to keep the relationship happy. The mathematical model also implies that when no effort is put in the relationship can easily deteriorate.

I have no argument with the theory or the math; this appears to be a case of math proving existing wisdom. But the more revelatory bit is the "effort gap", which implies that as long as you know you can get away with that much less effort, the relationship can be maintained. Which reads to my cynical mind that there will always be abusive long-term relationships, because people always want to make minimal effort for maximum gain. What I wonder is whether the effort gap will fluctuate over time, and I suspect that it will.

Not that I'm advocating that, mind you. I firmly believe that the effort gap should be as close as possible, but reality is that it will probably never be zero. Expecting complete reciprocity in human relationships is a fool's game.

(h/t: Andrew Sullivan)