Sun Sep 8, 2002

Look a Little Closer at the Data

Slate’s Mickey Kaus joins a distingushed line of snipers at social science as he makes fun of a study finding that mothers often have little idea that their children are sexually active. “New York Times … or The Onion? You Make the Call!” he snickers. “Next: A team of researchers discovers that when teenage women say they can’t go on social outings because they are “busy,” they often are not describing their schedules accurately: 45 percent are in fact not busy at all.”

I suspect his main motivation for highlighting this piece is to smack the Times around a bit, which seems to have become his main role in life. (I don’t know why this is so. But could it be… welfare reform?) I’m going to focus on the social science instead. I agree with Kaus that the finding the Times highlights is not especially shocking, I think. But, as is oten the case with reports like this, the dataset the study is based on has much more to it than the story might suggest. This particular study is out of the University of Minnesota Adolescent Health Center, but the data are from the National Longitudinal Study of Adolescent Health, also known as AddHealth. Two of the most interesting papers to come out of this data are written by Peter Bearman and Hannah Brückner. Both are published in the American Journal of Sociology. The more recent one is titled Opposite-Sex Twins and Adolescent Same-Sex Attraction (you’ll need a subscription to view the article, I think, but if you’re at a University you probably have one). Here’s the abstract:

The etiology of human same-sex romantic attraction is generally framed in terms of (1) social influences, (2) genetic influences, or (3) hormonal influences. In this article, we show that adolescent males who are opposite-sex twins are twice as likely as expected to report same-sex attraction; and that the pattern of concordance (similarity across pairs) of same-sex preference for sibling pairs does not suggest genetic influence independent of social context. Our data falsify the hormone transfer hypothesis by isolating a single condition that eliminates the opposite-sex twin effect we observe the presence of an older same-sex sibling. We also consider and reject a speculative evolutionary theory that rests on observing birth-order effects on same-sex orientation. In contrast, our results support the hypothesis that less gendered socialization in early childhood and preadolescence shapes subsequent same-sex romantic preferences.

Now I think that sounds pretty damn interesting. Even better, I think, is their other paper, titled “Promising the Future: Virginity Pledges and First Intercourse.” This one deals with the “True Love Waits” movement, where adolescents pledge to keep their virginity until marriage. Bearman and Brückner ask whether being in the movement has any effect on time of first intercourse. The abstract, again:

Since 1993, in response to a movement sponsored by the Southern Baptist Church, over 2.5 million adolescents have taken public “virginity” pledges, in which they promise to abstain from sex until marriage. This paper explores the effect of those pledges on the transition to first intercourse. Adolescents who pledge are much less likely to have intercourse than adolescents who do not pledge. The delay effect is substantial. On the other hand, the pledge does not work for adolescents at all ages. Second, pledging delays intercourse only in contexts where there are some, but not too many, pledgers. The pledge works because it is embedded in an identity movement. Consequently, the pledge identity is meaningful only in contexts where it is at least partially nonnormative. Consequences of pledging are explored for those who break their promise. Promise breakers are less likely than others to use contraception at first intercourse.

In other words, it’s an identity-based social movement. Joining delays first intercourse, but only when there are only a few other members. Interestingly, the mainstream media picked up on the finding that pledges work. But the most interesting point is that they don’t work unilaterally “If most adolescents were to pledge, there would be no pledge effect on the transition to intercourse,” say Bearman and Brückner. This means that it’s a mistake to advocate these movements as a sex education policy: the more people join the movement, the less effect it will have on behavior. That’s a lovely finding. It shows how the meaning of a pledge depends on its social context, and how a policy to promote such pledges would undermine its own effectiveness for that reason.

Kaus may be right to think that the finding reported in the Times wasn’t so earth-shattering. But there’s a lot more to this stuff than you read about in the papers.