By Anya Sostek Pittsburgh Post-Gazette.
It is Carnegie Mellon professor George Loewenstein's firm belief that, generally, married couples would be happier if they had more sex.
But a study that he published recently in the Journal of Economic Behavior & Organization found just the opposite.
Five years ago, Carnegie Mellon first started recruiting for the study that Loewenstein described as "extremely difficult to do."
For three months, half of the 64 married couples who participated in the study were told to double their current level of sexual activity, and half were given no instruction on changing their sexual frequency.
Those who increased their frequency had a slightly lower happiness level than couples whose sexual frequency remained unchanged. "They were, if anything, less happy," said Loewenstein, a professor of economics and psychology. "They ended up wanting sex less and enjoying the sex that they did have less."
Those in the increased sex group showed lower general mood indicators, most reporting significantly less energy and less excitement than those with unchanged sex levels.
Prior to participating, couples in the study had sex between once a month and three times per week. Couples were paid for participating in the study, funded in part through a grant from the Pennsylvania Department of Health. Other researchers on the study included Tamar Krishnamurti, Jessica Kopsic and Daniel McDonald.
The study was conceived based on ample previous research showing a correlation between sex and happiness, a 2004 study published by the National Bureau of Economic Research, for example, found that an increase in sexual frequency from once a month to once a week would equate in happiness levels to a $50,000 pay raise.
But those studies left open the question of whether people were happier because they were having more sex, or having more sex because they were happier. No study before this attempted to establish which caused which, said Loewenstein.
So why were the results of this study so different from what he expected? He still believes that most married couples would be happier if they had more sex, he just doesn't think that being told to do so by an external researcher is the best way to accomplish that happiness.
"Perhaps being in the experimental treatment changed couple members' construal of sex, from a voluntary activity engaged in for pleasure to a duty, engaged in at the behest of the experimenter," said the study, which noted that studies of sexual satisfaction in couples undergoing infertility treatment show similar results.
The study considered the possibilities that the amount of sex expected by the study might have pushed couples beyond their optimum levels, or made them excessively tired, but dismissed those theories based on the evidence.
The theory behind the research is that individuals have a "hot-cold empathy gap," a term coined by Loewenstein to explain that when someone is in one emotional state, it's very difficult to imagine how they might feel in a different emotional state.
When people are not aroused, he said, it is difficult to make decisions based on how they would feel if they were.
His hope was that the study, by using external motivation to increase sexual frequency, would help couples overcome that gap.
And though he likely won't be revisiting this particular study, he still believes the theory has merit.
"I still believe that it's good for couples to have more sex," he said. "My beliefs are so strong on this issue that I'm not ready to overturn them based on this one study."