The researchers have also found a link between sexual inhibition and sexual risk-taking: men who are low in inhibition do not necessarily engage in more or kinkier sex than do their high-inhibition counterparts, but the odds are greater that they will forgo condoms if they indulge.

Most of the studies on the autonomy of sexual brakes and accelerators have been done on men, but scientists lately have begun applying the dual-control model to their studies of female sexuality as well. At first they used a slightly modified version of the excitement/inhibition questionnaire that had proved valuable for assessing men, but they soon realized that their menu of sex situations and checklist of physical arousal cues might be missing large swaths of a woman’s sexual persona.

What was the feminine equivalent of an erection anyway? Was it vaginal swelling and lubrication, or something else entirely? Women are generally smaller and less muscular than men. What might the feeling of being physically threatened do to enhance or hamper a woman’s sexual appetite?

“We started putting together focus groups, asking women to tell us the various things that might turn them on and turn them off sexually, and how they know when they’re sexually aroused,” said Stephanie A. Sanders of the Kinsey Institute and Indiana University. “They mentioned a heightened sense of awareness, genital tingling, butterflies in the stomach, increased heart rate and skin sensitivity, muscle tightness. Then we asked them if they thought the female parallel to an erection is genital lubrication, and they said no, no, you can get wet when you’re not aroused, it changes with the menstrual cycle, it’s not a meaningful measure.”

Through the focus groups, Dr. Sanders and her colleagues compiled a new, female-friendly but admittedly cumbersome draft questionnaire that they whittled down into a useful research tool. They asked 655 women, ages 18 to 81, to complete the draft survey and scrutinized the results in search of areas of concurrence and variability.

The researchers have identified a number of dimensions on which their beta testers agreed. For example, 93 to 96 percent of the 655 respondents strongly endorsed statements that linked sexual arousal to “feeling connected to” or “loved by” a partner, and to the belief that the partner is “really interested in me as a person”; they also concurred that they have trouble getting excited when they are “feeling unattractive.”

But women’s tastes varied widely in many of the finer details of seduction and setting. “Some women say they find the male body odor attractive, others repulsive,” Dr. Sanders said. “Some women are turned on by the idea of having sex in an unusual or unconcealed place where they may be caught in the act, while others have a hard time getting aroused if they think others may hear them, or the kids will walk in.”