If you cheated on your spouse, would you admit it to a researcher?
That question is one of the biggest challenges in the scientific study of marriage, and it helps explain why different studies produce different estimates of infidelity rates in the United States.
A handful of new studies suggests surprising changes in the marital landscape. Infidelity appears to be on the rise, particularly among older men and young couples. Women may be closing the gap: Younger women appear to be cheating on their spouses nearly as often as men.
"If you just ask whether infidelity is going up, you don't see really impressive changes," said David Atkins, research associate professor at the University of Washington Center for the Study of Health and Risk Behaviors. "But if you magnify the picture and you start looking at specific gender and age cohorts, we do start to see some pretty significant changes."
The most consistent data on infidelity come from the General Social Survey, sponsored by the National Science Foundation and based at the University of Chicago, which has used a national representative sample to track the opinions and social behaviors of Americans since 1972. The survey data show that in any given year, about 10 percent of married people - 12 percent of men and 7 percent of women - say they have had sex outside their marriage.
But detailed analysis of the data from 1991 to 2006, to be presented next month by Atkins at the Association for Behavioral and Cognitive Therapies conference in Orlando, shows some surprising shifts. University of Washington researchers have found that the lifetime rate of infidelity for men over 60 increased to 28 percent in 2006, up from 20 percent in 1991. For women over 60, the increase is more striking: to 15 percent, up from 5 percent in 1991.