Why were the participants’ estimates so far off?
Conley and her colleagues think the answer has to do with stigma: Risky behavior related to sex is judged more harshly than comparable (or even objectively worse) health risks, when you control for the relevant differences between the behaviors.
“It seems that as a culture we have decided that sex is something dangerous and to be feared,” Conley told me in an interview. That’s why, she argues, U.S. parents try to “micromanage” their children’s sexuality, “with the danger of STIs [Sexually Transmitted Infections] being a large part of that.”
At the same time, “parents are excited about kids getting their driver's licenses, and do not regularly forbid their child from driving … they know there are risks but assume the kids must learn to manage those risks.”
She thinks this approach should be applied to sex as well.
Of course, there could also be a moralistic aspect here—a kind of hangover from America’s Puritan founding. I raised this possibility with Shaun Miller, a philosopher at Marquette University who focuses on love and sexuality. “I'm not sure if it relates to our Puritan values,” he told me, “but I do think the stigma is a proxy for moral judgment. Sexuality has always had to do with one's moral character, and so if one has an STI, it suggests that one's character is ‘infected’ as well.”
To test this idea that sex-related risks are more stigmatized than other types of risk, Conley and her colleagues ran a follow-up study. In the study, they wanted to control for some of the differences between driving cars and having sex—two activities that both carry risk, sure, but which are different in other ways.
If these differences could somehow explain the weird estimates that participants gave in the first study—without having anything to do with sex-related stigma, specifically—it would undermine Conley’s theory.
Conley and her team designed a test that would compare “apples to apples”—two cases where a health threat was transmitted through sex, but only one of which was an actual STI.
They gave a collection of 12 vignettes to a large number of participants—one vignette per person. All of the vignettes told the same basic story: Someone transmits a disease to someone else during a casual sexual encounter, without knowing that they had something to transmit. There were two diseases: either chlamydia, a common STI that rarely causes serious health problems (and that can be completely cured with a course of antibiotics), or H1N1—commonly known as the swine flu—which can be seriously bad for your health or even kill you.
The main thing they manipulated between the different vignettes was the severity of the outcome caused by the disease. A “mild” outcome was described as getting sick enough to have to see the doctor, and then take a week’s worth of medicine. A “moderate” outcome was the same, except that you had to go to the emergency room first. A “serious” outcome was getting hospitalized and nearly dying. And a “fatal” outcome was, well, dying.