Porn stars aren't particularly keen on being studied. But they are the focus of great public interest and moral debate, which may explain why one man's in-depth analysis of adult film performers went viral last week.
The average adult film actress is a brunette with a B-cup named Nikki, at least according to blogger Jon Millward, who spent six months analyzing the demographics of 10,000 porn stars drawn from the Internet Adult Film Database. But what's known about porn stars beyond their breast size? Remarkably little, thanks to practically zero research funding and a community wary of researchers.
"The average span of a performer's career is usually only about six to 18 months, so the benefit of participating in these things isn't usually apparent to the people who are in it at the time," Kayden Kross, an adult film actress and writer, told LiveScience.
Not only that, Kross said, but many actresses are reluctant to help researchers, because they're worried that the studies will be used against them by anti-pornography activists. [ The Sex Quiz: Myths, Taboos and Bizarre Facts ]
"The difficulty with this population has always been access," said James Griffith, a psychologist at Shippensburg University in Pennsylvania and one of the few scientists to delve into the subject. "It's a very difficult population to define."
This lack of research is notable given the number of stereotypes about porn actresses, particularly that they have high rates of childhood sexual abuse and psychological problems. Though it's hard to know for sure without more extensive studies, early explorations have found these stereotypes fail to hold up. Ultimately, the findings could lead to better understanding of sexual health, sexual identity and other aspects of the high-grossing porn business.
Stereotypes were the motivation for Millward, whose analysis of porn stars includes a facial composite of the "average" actress.
The stereotypical porn actress — with enormous breasts and blonde hair — doesn't match reality, Millward found. In fact, the most common bra size among porn stars is a 34B, compared with 36C for the average American woman. High obesity rates among the public may explain some of the discrepancy in breast size; porn actresses are also thinner than the average American woman. According to the numbers given on Internet Adult Film Database profiles, the average female porn star weighs 117 pounds (53 kilograms), which is 48 pounds (22 kg) less than the average American woman. [ 5 Myths About Women's Bodies ]
The average male porn star weighs 167.5 pounds (76 kg), 27 pounds (12 kg) less than the national average of 195.7 pounds (89 kg) for men.
Nor are blondes as dominant as might be expected. Only 32.7 percent of porn actresses have blonde hair, whether natural or dyed. About 39 percent have brown hair, 22.5 percent have black hair, and only about 5 percent are redheads.
Nikki is the most common name for female porn stars, Millward found, and David is the most common name for men.
The psychology of pornography
Millward's data is not published in a research journal or peer-reviewed by experts, so scientists like Griffith take it with a grain of salt. (Millward plans to make his methods available on his website.) Kross, however, said the results didn't surprise her.
"There have been more brunette stars than blonde stars," she said. "It's just that those stars have never been as big as the blonde stars."
Meanwhile, academic research on the porn star population is lacking.
Part of the reason is that there just aren't that many porn stars — about a thousand working at any given time, Kross said. Add to that short career spans, a reluctance to be put under the microscope and a population of performers centered in Los Angeles County, where many researchers don't have the luxury of spending time, and it's a recipe for lack of research.
Another barrier is funding. Griffith conducted his study on pornography without the benefit of outside money.
"I didn't even attempt it," he told LiveScience. "I don't know of anyone that would fund a study on characteristics of people in the adult entertainment industry."
Porn isn't Griffith's typical area of research (he studies risk-taking and decision-making), but he decided to look into it after a question from an undergraduate student in a lecture on human sexuality made him realize how little research on porn actors has been done.
He advertised for volunteers at the Adult Industry Medical Healthcare Foundation, a now-defunct medical organization that used to administer mandatory tests for sexually transmitted infections to industry actors (tests are now done elsewhere).
Though the majority of porn stars would have used the Foundation's services, the volunteer sample makes it hard to know if the 177 actresses who agreed to participate in the study represent the industry as a whole. Nevertheless, the study is the largest sample of porn stars ever published.
The results of the research failed to support many common stereotypes. Most notably, the porn actresses were no more likely to report having been sexually abused as children than national averages or than a sample of demographically matched women Griffith and his colleagues recruited at a university and at an airport.
Porn actresses did report having sex for the first time at a younger age and having more partners (outside of work) than the typical woman, which is unsurprising, Griffith said, given that they likely got into the adult industry because they liked sex. (Of the 177 women surveyed, only one said she was coerced into a pornography career.) Sixty-nine percent of porn actresses ranked their enjoyment of sex as 10 out of 10, a rating given by only 32.8 percent of non-performers. [ 10 Surprising Sex Statistics ]
Porn actresses were also more likely to report higher self-esteem than average women, another unsurprising finding, Griffith said.
"They do have to be comfortable with themselves in order to engage in intercourse in front of other people on camera," he said.
Kross warned that the finding that porn actresses enjoyed sex more than other women might be unreliable, given that a porn star's public image relies on her fans' belief that she thinks sex is the "greatest thing on the planet." But the self-esteem finding did not surprise her.
"All you hear from fans is, 'Oh, you're so wonderful, I wish I had a girlfriend like you,'" she said. "The fan base just adores us. They worship us online, and we hear it every day."
The stereotype that porn stars use more drugs than the average person was partially true, Griffith and his colleagues found. Porn actresses had tried more drugs than other women, though the only difference in recent drug use was a higher prevalence of marijuana smoking. The drug use could be linked to the personality of people who get into the industry, Griffith said.
"Maybe they're higher risk-takers," he said.
Kross agreed. "I have a feeling we've probably, as a demographic, tried skydiving more," she said. "We've probably tried monkey brains in South Africa more."
Griffith and his colleagues reported their findings in the International Journal of Sexual Health in September 2012. They also asked performers their reasons for entering the industry, and found that money was the primary driver, followed by fame.
This research is a "first step," Griffith said. The sample was limited, based on self-reports and focused on performers in the United States. Griffith doesn't have plans to pursue the research further, though he hopes other researchers will. One particularly interesting finding, he said, was that two-thirds of the porn actresses said they were bisexual. It's not clear whether they identified this way before they entered the industry or whether they began seeing themselves as bisexual after doing popular woman-on-woman scenes.
"Engaging in that behavior while they're in the industry, is that related to them identifying as bisexual or not?" Griffith said. "If it is the case, that could be applied to theories of bisexuality."
More work is also needed on rates of sexually transmitted infections in the industry and the effect on a performer of contracting one, he said. In 2012, a measure requiring porn stars to wear condoms passed in Los Angeles. In January, Vivid Entertainment and performers Kross and Logan Pierce filed a lawsuit to challenge the law on freedom of speech and anti-censorship grounds.
Mental health is important, Griffith said, but "I think the more important question has to do with physical health."