Friday, March 18, 2011

Nerd Friday: David Brooks And No-Sex-On-First-Date Research

Today Brooks tells us on his blog that delaying sex makes relationships stronger:
Today we rise up in defense of traditional values. For example, is it a good idea to have sex with somebody on the first date? Probably not. In the Journal of Family Psychology, Dean Busby, Jason Carroll and Brian Willoughby studied the effect of sexual timing on later marriage relationships. They found that couples who waited before engaging in sex for the first time went on to have higher relationship satisfaction, even after controlling for education, the number of sexual partners, religiosity and relationship length.
From that Brooks goes on to muse about whether the cause for this finding is in "impulsivity" or mores. Now it could be that the Busby, Carroll and Willoughby study has some neat way of defining impulsiveness. Or it could be that Brooks pulled that one out if his...hat. Likewise for sexual mores, I suspect.

I actually have nothing against the idea of no sex on the first date, but I'm pretty unconvinced that having sex on the first date is what makes relationships turn bad.

Neither does Brooks think so. He seems to believe that perhaps people who are impulsive cannot control themselves on the first date or even later on, and that relationships with impulsive people are less satisfactory for everyone, including the impulsives themselves.

His alternative theory is that people with more rigid sexual mores end up with happier relationships overall. His conclusion combines the two theories:
On the other hand, if you took impulsive people and surrounded them in a culture that strongly discouraged bedding down on the first date, would this by itself improve relationship quality?
My guess is it would, at least a little,

A hilarious conclusion! If it is impulsiveness that causes relationships to go sour, the social mores haven't done anything to stop that after the no-sex-on-first-date. If it's sexual mores themselves, those who don't agree with them won't be affected. And note how he back-pedaled from his original thoughts about impulsiveness and sexual mores? Now it is indeed that first bedding which causes the later problems, and if only we could stop it, well, all relationships would be like chocolate ice-cream! Meaning excellent.

Mmm. Let's have a closer look at the study Brooks uses here. From Science Daily:
The study involves 2,035 married individuals who participated in a popular online marital assessment called "RELATE." From the assessment's database, researchers selected a sample designed to match the demographics of the married American population. The extensive questionnaire includes the question "When did you become sexual in this relationship?"
A statistical analysis showed the following benefits enjoyed by couples who waited until marriage compared to those who started having sex in the early part of their relationship:
Relationship stability was rated 22 percent higher
Relationship satisfaction was rated 20 percent higher
Sexual quality of the relationship was rated 15 percent better
Communication was rated 12 percent better
For couples in between -- those that became sexually involved later in the relationship but prior to marriage -- the benefits were about half as strong.

Nothing about "impulsivity" there Not even sexual mores are mentioned! And the research does seem to recommend abstinence-until-marriage which Brooks decided not to touch.

The three authors of the study are all professors at the Brigham Young University. If I have the correct RELATE reference, their sampling frame, the place which they used to find their sample of 2035 married individuals, is this:
RELATE was developed by the Marriage Study Consortium at Brigham Young University. Founded in 1979, the Marriage Study Consortium is a non-profit organization with the specific tasks of developing research and outreach tools that can be used directly with the public and that can be used to gather information about relationships. The consortium consists of a group of scholars, researchers, family life educators, and counselors from varied religious and educational backgrounds who are dedicated to strengthening and understanding premarital and marital relationships.
Brigham Young again. That's not necessarily a problem (though the original Brigham Young certainly had a different idea of marriage) though one might want to be careful when all evidence and all research comes from the same place.

But what certainly IS a problem is the use of the RELATE site as the sampling frame, and trying to pick a sample from that site "designed to match the demographics of the married American population" doesn't fix it. Here's why:

People who filled in the questionnaires at the RELATE site did so by their own choice, not because they were randomly assigned to do so.

Statisticians have a name for this problem: self-selection bias, and it cannot be corrected by picking a sample which otherwise matches the demographics of married Americans. Such a sample has not corrected for the fact that the individuals in the final sample ONLY consist of the ones who filled in the questionnaire in the first place.

If those who did not fill such a questionnaire are different in their marital satisfaction ratings, the study doesn't tell us anything that can be generalized to them. And the odds are that those who answered the questionnaire are different from those who never did. For instance, the former may be more dissatisfied with their marriages or less wary about the Brigham Young University and so on.

I'm not sure if writing about Brooks' theories about the universe, everything and what is wrong with the young (women, mostly) is worth my time. But I don't think research should be used as a propaganda tool and it angers me when that happens.