Wednesday, January 30, 2013

An Evolutionary Psychology Perspective on Porn Stars

Although a great body of psychological research has examined pornography, there has been a paucity of studies focusing on performers in this profession. A recent paper (Griffith, Mitchell, Hart, Adams, & Gu, 2012) testing whether or not female pornography actresses are in fact “damaged goods” has attracted widespread attention. Two other papers have been published by the same lead author, one discussing what motivates women to work in pornography (Griffith, Adams, Hart, & Mitchell, 2012)  and the other looking at male performers (Griffith, Mitchell, Hammond, Gu, & Hart, 2012). The findings confirm some but disconfirm other popular stereotypes about porn actors and actresses. The studies also raise a number of interesting questions. Evolutionary psychology theories about variations in human sexual behaviour might shed light on the particular motivations of porn stars. For example, one intriguing prediction based on evolutionary psychology is that female pornography actresses might have more sons than daughters compared to other women. This hypothesis remains to be tested. 

Jenna Jameson, considered the world's most famous porn actress. © Glenn Francis, 

Past research into performers in the porn industry has run into difficulty because of this population to talk to the researchers. The industry apparently tends to be a rather closed and secretive world and actors tend to keep to themselves, perhaps due to the social stigma attached to their work. Sharon Mitchell, a coauthor of the recent papers on this topic, actually works in the industry and also founded a medical foundation that provides STD testing for pornography performers. Participants in these studies were therefore recruited through a clinic that provides such testing.  

The findings of the “damaged goods” paper have been summarised in detail elsewhere, for example, in this post. To recap briefly, contrary to the stereotypical view of pornography actresses as women psychologically damaged by an abusive upbringing, the study found that these women were no more likely to have been sexually abused as children than women in a matched control group drawn from the general population. Additionally, among other findings, pornography actresses reported higher self-esteem, and sexual satisfaction than other women. Similar results were found for male actors compared to men in a control group, contrary to stereotypes of these men as teenage runaways escaping abusive homes (Griffith, Mitchell, Hammond, et al., 2012). In regards, to the performers’ sexuality, the results are probably more in accord with popular stereotypes. Both male and female performers reported having their first sexual experience at a younger age than other people and reported having had a far larger number of sexual partners. Note that when answering this last question, participants were asked NOT to include people they had had sex with only as part of their work, so these are sexual partners from their private lives. In fact, when asked to indicate the number of sexual partners in the last 12 months, the average number for porn actresses was larger than the average number of partners that ordinary women had had in a lifetime. Interestingly, the average number of lifetime partners reported by male actors (about 170) was notably larger than that for actresses (about 75). Perhaps future studies will shed some light on why there is such a large difference. Both figures are much larger than the averages for men (about 10) and for women (about 5) in the control groups though.

Sharon Mitchell co-authored recent papers on the porn industry

Also of note was that both male and female performers indicated that they enjoyed sex more on average compared to their control groups. For example, on a 10-point scale, porn actresses rated their enjoyment of sex on average as 9.40 compared to other women with an average score of 8.28. This may not seem like a huge difference at first, but the researchers noted that 69% of porn actresses rated their enjoyment as 10 out of 10, compared to 33% of other women. Additionally, less than 2% of actresses rated their enjoyment as 5 or less, compared to about 12% in the control group. Among the men, 83% of porn actors rated their enjoyment of sex as 10 out 10, compared to 51% of the control group males. Only one of the male actors in the study rated his enjoyment as less than 5, compared to about 8% of the control group.  

One striking difference between male and female performers was in sexual orientation. The vast majority of male actors identified as heterosexual, with only 8 bisexual and 2 homosexual (out of 105 participants), similar to the control group. In contrast, among the actresses, over 67% identified as bisexual, and the remainder were heterosexual except for one lesbian. (Among the control group women, over 92% identified as heterosexual, about 7% as bisexual, and the remainder as lesbian.)

What seems very clear from these studies is that both male and female performers have unusually high levels of sexual desire and a willingness to have sexual relations with a large number of partners. In psychology, a person’s willingness and desire to have uncommitted sexual relations is known as sociosexuality. (Lay people might simply use the word promiscuity.) Sociosexuality has been of considerable interest to evolutionary psychologists who are interested in understanding the diversity of human mating strategies. Porn stars would appear to be at the extreme end of the scale in sociosexuality. There is evidence that sociosexuality is to an extent heritable and evolutionary psychologists have argued that it represents part of an evolved mating strategy (Gangestad & Simpson, 1990).

Evolutionary psychologists have argued that humans have developed a number of different mating strategies to ensure their reproductive success. People with a restricted strategy require considerable commitment to and investment in a relationship from a partner before they will engage in sexual relations. People with a more unrestricted strategy require much less commitment or investment and may be willing to enter quickly into sexual relations with a new partner. In the general population, men are usually higher than women in sociosexual tendencies, so the fact that female porn actresses appear to have such high sex drives is even more unusual. From an evolutionary perspective it has often been thought that men tend to be less sexually restricted than women because they invest less in reproduction and have the potential ability to impregnate many partners. Women on the other hand invest heavily in reproduction and can only have one pregnancy at a time. Therefore, they might be expected to be more selective than men in regard to who they have sexual relations with. But if this is the case, how to explain the fact that some women have a relatively unrestricted sociosexual orientation, while some men are highly faithful to their partners?

In order to explain this, evolutionary psychologists have developed more sophisticated theories that acknowledge that each sex may choose from more than one kind of mating strategy. In particular, individuals of either sex may tend to specialise in a particular mating strategy.[1] Women with a restricted sociosexual orientation will prefer partners who demonstrate their willingness to invest time and resources into the relationship and provide for her children. Women with an unrestricted orientation seek partners who show signs of high quality genes associated with reproductive success, in order to pass these genes onto their children. That is, they will seek to mate with men who are highly physically attractive and/or have high social status. These kinds of men in their turn will find unrestricted women preferable to more restricted women who demand more relationship exclusivity, as they seek to mate with as many women as possible. Less exciting but more reliable men who have much less chance of being successful in mating with many partners will for their part find it more profitable to appeal to more restricted women and therefore be more willing to commit to long-term relationships.[2] These two broad kinds of strategies will tend to maintain a balance with each other over time because people who specialise in one kind of strategy tend to compete most intensely with each other for mates. Thus, for example if most women in a population pursue a restricted strategy they will be in very intense competition with each other for men willing to commit to them. In this situation, the minority of unrestricted women will have a competitive advantage and will become highly sought after by attractive males. On the other hand, if the unrestricted orientation becomes too common, these women will experience more competition with each other.

Jesse Jane states "I've always been an extremely sexual person and I knew I would like to do videos." 
© Glenn Francis, 

One prediction made by this theory is that women with an unrestricted orientation will tend to produce more sons than daughters (Gangestad & Simpson, 1990). Their sons are more likely than daughters to benefit from inheriting the characteristics that made their fathers reproductively successful. This is because males tend to have greater variability than women in their reproductive success. That is, some men will have many more children than others, whereas the number of children women can have is in a narrower range. Women with a more restrictive orientation on the other hand will benefit from having more daughters. This is because these women are less likely to mate with highly reproductively successful males (after all, men who commit to a single woman forego mating opportunities and in that sense reduce their success) and their sons will therefore be less likely to be highly attractive, highly sought after men.  

Gangestad and Simpson actually tested this theory and found that women who rated themselves as more sociosexually unrestricted did tend to have more sons than daughters compared to more restricted women. These tended to be small effects, which is understandable considering that random factors beyond the mother’s control substantially influence the child’s sex. However, based on their estimates they claimed that individuals with an extremely unrestricted orientation (for the stats minded, two standard deviations above the mean) would be expected to produce about 50% more sons than individuals at the other extreme of restrictedness (that is, two standard deviations below the mean).

Based on the foregoing, it might be concluded that porn performers are for the most part people who have inherited tendencies to extreme sociosexuality and that the payoff from an evolutionary perspective is that the men get to mate with many women and that the women get to mate with highly reproductively successful men and therefore have the opportunity to pass these men’s genes onto their sons. As far as I know, no studies have surveyed whether female porn stars have more sons than daughters compared to other women, but if Gangestad and Simpson’s theory is correct we would expect there to be a noticeable difference.

At this point, one might object that the idea that women can influence what sex their children are seems rather silly, as the child’s sex is determined by chromosomes on the father’s sperm. Fortunately, for our theory so far, research has found evidence that some women actually do seem to influence the sex of their children to an extent. Studies have found for example that women high on the personality trait of interpersonal dominance tend to have more sons than daughters compared to less dominant women (Grant, 1992; Grant & France, 2001). Dominance in women is associated with heightened testosterone levels, and there is evidence that maternal testosterone levels (in humans as well as other mammals) can influence the child’s sex in favour of conceiving a male (Grant, 2007). (Many lay people are surprised to learn that women’s bodies produce testosterone at all, but this is actually perfectly normal for women. Where men differ from women is that their testosterone levels are many times higher.)   

Furthermore to this, interpersonal dominance in both men and women is associated with having more sexual partners (Markey & Markey, 2007). Therefore, I would predict that female porn actresses are probably not only higher in sociosexuality, but also more interpersonally dominant compared to other women and have higher testosterone levels. Heightened levels of testosterone during foetal development have also been linked to bisexuality in females. Additionally, bisexual women tend to be higher in sociosexuality compared to heterosexual women and lesbians (Schmitt, 2007). Female porn stars were found to predominantly identify as bisexual, although it was not clear in the study if they considered themselves bisexual mainly due to the requirements of their work in the pornography industry, or if they had always considered themselves this way. There does seem to be a pattern emerging here that might suggest that high testosterone levels may be a key feature that underlies a number of characteristics that may be common in female porn actresses. Only further research will determine whether these conjectures are accurate.

This article has previously appeared on my blog Unique - Like Everybody Else at Psychology Today. 

Further reading:
The Personalities of Porn Stars (a follow-up to the present article)

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© Scott McGreal. Please do not reproduce without permission. Brief excerpts may be quoted as long as a link to the original article is provided.
Gangestad, S. W., & Simpson, J. A. (1990). Toward an Evolutionary History of Female Sociosexual Variation. Journal of Personality, 58(1), 69-96. doi: 10.1111/j.1467-6494.1990.tb00908.x
Grant, V. J. (1992). The measurement of dominance in pregnant women by use of the simple adjective test. Personality and Individual Differences, 13(1), 99-102. doi:
Grant, V. J. (2007). Could maternal testosterone levels govern mammalian sex ratio deviations? Journal of Theoretical Biology, 246(4), 708-719. doi:
Grant, V. J., & France, J. T. (2001). Dominance and testosterone in women. Biological Psychology, 58(1), 41-47. doi:
Griffith, J. D., Adams, L. T., Hart, C. L., & Mitchell, S. (2012). Why Become a Pornography Actress? International Journal of Sexual Health, 24(3), 165-180. doi: 10.1080/19317611.2012.666514
Griffith, J., Mitchell, S., Hammond, B., Gu, L., & Hart, C. (2012). A Comparison of Sexual Behaviors and Attitudes, Self-Esteem, Quality of Life, and Drug Use Among Pornography Actors and a Matched Sample International Journal of Sexual Health, 24 (4), 254-266 DOI: 10.1080/19317611.2012.710183
Griffith JD, Mitchell S, Hart CL, Adams LT, & Gu LL (2012). Pornography Actresses: An Assessment of the Damaged Goods Hypothesis. Journal of sex research PMID: 23167939
Markey, P. M., & Markey, C. N. (2007). The interpersonal meaning of sexual promiscuity. Journal of Research in Personality, 41(6), 1199-1212. doi:

Schmitt, D. P. (2007). Sexual Strategies Across Sexual Orientations. Journal of Psychology & Human Sexuality, 18(2-3), 183-214. doi: 10.1300/J056v18n02_06

[1] It should be acknowledged that the same individual may alternate between different sexual strategies at different times in his or her life. However, in order to keep things clearer I will focus here on stable strategies a person may specialise in.
[2] In the evolutionary psychology literature, men of the unrestricted type are referred to as ‘cads’ while men of the restricted type are referred to as ‘dads’. Apparently there is a third category of men who combine high physical attractiveness with high willingness to commit to family life who are known as ‘brads’ after Brad Pitt. These men are thought to be quite rare though sadly. 


  1. Most of the above blog is a contradiction of the Biological Perspective which has to do with genetics. Gender is decided by the x or y chromosome in the sperm, which is in the father. The mother just has the egg. No matter the level of interpersonal dominance in the female performer, the male sperm will decide the gender. However, this is a very interesting conclusion from the evolutionary point of view. Congradulations Darwin and goodbye Brad Pitt.

    1. It is true that ultimately the sex of the child is determined by the chromosome on the father's sperm. However, there is evidence that the mother's hormones can influence the chemistry of the uterus in ways that make it more probable that a sperm bearing either an X or Y chromosome will fertilise the egg. Specifically, this has been linked to testosterone levels in the follicular fluid surrounding the ovum. Higher testosterone levels appear to increase the chance that the egg will be fertilised by a Y-bearing sperm. I'm not saying this has been conclusively proven, but there does appear to be a plausible mechanism by which the mother could influence the sex of her child. Thanks for taking an interest.

  2. Evolutionary perspective refers to the application of the principles of evolution to explain psychological processes and phenomena(Buss, 2009). The confidence that these male and female performers have, is said to be passed down to their offspring. The evolutionary perspective analyzes behaviors in terms of how it increases a species' chances to survive and reproduce(Hockenbury, 2010). I think that the idea that these women, that reproduce with attractive men that are more reproductively succesful, have a tendancy to have sons that will be good looking as well as be reproductively successful. From my understanding of the evolutionary perspective of psychology, I agree with this post and thought it was very interesting!

    1. Thanks for your comment, I'm pleased you found it interesting!