Have you ever faked an orgasm? Has your partner? If so, why?

Although it has long been a part of the popular imagination (who hasn't seen that obnoxious Meg Ryan scene, or one of the thirty-five episodes of "Sex and the City" devoted to the topic?), the fake orgasm has not received much systematic scientific study.

One problem with studying faking is that such a study relies on asking people about behavior they are not necessarily proud of. People don't like to admit they lie. Ask them if they lied, and odds are they will lie and say they haven't.

Either way, by the bulk of existing data, most of which is based on self-reports of American women, somewhere between one half and two thirds of women have faked an orgasm at some point. Surprisingly perhaps, it turns out that men fake, too. Male orgasm faking has received even less scholarly attention, probably because male orgasm is both more easily achieved and more difficult to fake. After all, contrary to the female orgasm, which is rather unpredictable and lacks definitive outward signs, the male anatomy provides multiple forms of evidence for orgasm, including physiological (ejaculation; subsiding of erection) and behavioral (falling asleep).

In 2009 researchers at the University of Kansas surveyed several hundred students about their experiences with--and reasons for--faking orgasms. About one quarter of males and one half of females admitted to faking. Faking for both sexes occurred most frequently during intercourse, and more often with steady partners than with one night stands; moreover, no correlation was found for either sex between ease of achieving orgasm and frequency of faking. In other words, those who faked did not do so because they were generally less orgasmic.

Why did those who faked do it? Reasons were quite similar across the sexes. Both faked mainly to end the session, having figured that real orgasm was not likely, or having had their interest or energy exhausted. But some important differences did emerge. When a man fakes an orgasm, sex is over. A woman fakes to signal to the man to come so sex can end.

Interestingly, both sexes faked so as to protect their partner's feelings. Both reported often heaping praise on the partner after faking. But faking so as not to hurt the partner's feelings was more common in women. Perhaps this is because women are well aware of the fragility of the male ego. But maybe evolution is also in play. Recent research has provided evidence that women fake orgasm more when they feel their partners are thinking of leaving the relationship. Some evidence exists pointing to the possibility that female orgasm may serve the evolutionary function of facilitating conception. Studies have also shown that women tend to reach orgasm more with testosterone heavy, symmetrically-built males. In orgasm, certain hormones are released, contractions occur, and even internal changes in air pressure are documented, all of which may facilitate conception. A real female orgasm signals to the male that his sperm has been chosen for fertilization, and thus reduces his incentive to stray. A fake orgasm, if convincing, may do the trick just as well.

How were orgasms faked? Both men and women relied largely on similar strategies, including vocalizations, changes in breathing, increased thrusting, and then stopping and feigning fatigue. But gender differences did emerge. Women relied significantly more than men on vocalizations to convey orgasm. This difference in the reliance on sexual sounds to convey sexual states may again relate to the genders' different physiology. As mentioned, male sexual arousal, excitement, and orgasm are signaled by rather clear external cues. You can touch and feel a man's erection, which signals arousal quite reliably. You can't fake an erection.

The female signals are more ambiguous. Vaginal lubrication, for example, can be achieved with artificial means (oil; saliva), and is also not a reliable sign of arousal. In fact, sex researchers' habit of equating penile tumescence with vaginal lubrication as the ‘his' and ‘hers' arousal indicators may be misguided; the vagina lubricates for a variety of reasons, not all of which are related to desire; moreover, in physiology, shape, and response patterns, the penis resembles much more the clitoris. Unlike the penis, however, the clitoris doesn't harden, and it extends mostly inwards. Thus, the male is more dependent for feedback on the indirect evidence of female vocalizations. Evolutionarily speaking, this may be why female sex noises are so arousing to men, and why porn actresses (a question: why is everyone who works in porn movies called a ‘star'?) tend to exaggerate their moans and cries and shrieks of ecstasy, so much so that the viewer may at times lose the thread of the plot in all the commotion.

The finding that people fake orgasm does not constitute an earth shattering (ha!) discovery. Faking in general is a well known phenomenon within the social-interpersonal realm. We fake, lie, and deceive routinely in our day-to-day lives. However, when it comes to science, lies can reveal important information. When we lie, we often unwittingly expose our true expectations and the social scripts that undergird our behavior. If you fake an orgasm in order to achieve a certain goal--say the end of a sexual encounter--then we know that you and your partner have an expectation that orgasm means the end of sex.

As I've written here before, our behavior as a whole is not free, spontaneous, or random. In fact, it is directed by powerful rules, mores, and habits acquired in the course of socialization. In other words, our movement in the social space is scripted. Our scripts are learned in a social context, through our interchange with others around us. This allows us to move in the social world seamlessly and effectively, minimizing confusion and conflict. For example, when you decide to go out to eat, a ‘restaurant visit' script is activated (walk in, wait, be seated, check the menu, order, wait, eat, pay, leave). This script is flexible enough to fit almost any restaurant. It's also flexible enough to allow you to embellish it with your own idiosyncratic personal touches (you never have dessert; and no ice in your water, please). In this way, you are able to adhere and conform while still feeling unique and free. Everyone wins.

Our movement in the world is scripted and organized like this even in areas we consider intimate and private, such as the bedroom. Like other scripts, your sexual arousal script integrates commonly-held social norms (high heels are sexy) with personal preferences picked up by your particular experience and temperament (if he bites the back of my left knee while at the same time caressing my elbow--I'm there).

Generally, then, the sexual encounter is as scripted as the restaurant trip. As much as your sex life seems wild, spontaneous, original and free-form to you, it is still directed and bounded by a subterranean system of rules and habits. The way you fake your orgasm allows scientists a glimpse into that system.