Posted by James
Fri, 31 Aug 2007 07:35:00 GMT
Tonight, my roommate and I chanced upon a documentary on the life of Jenna Jameson, the most famous porn star of all time, on the E! Channel. What amazed us, beyond how amazingly sexy she looks still, is her passion. Granted, her passion is for porn, but it's passion nonetheless. Too many people today, especially young women, possesses neither passion nor ambition. Jenna is the exact opposite of that, and I think her passion and intelligence is what made her so successful (much more so than her breast implants).
After watching the show, I went into my library and dug out a paper written by two social psychologists titled Pornography's Impact on Sexual Satisfaction [pdf]. In this paper the authors performed an experiment and determined that pornography decreases sexual satisfaction and happiness related to sex and relationships.
The study involved 160 volunteers randomly divided into several groups. One set of groups were made to watch pornographic films while the other set watched non-pornographic movies. The researchers were very careful to obscure the purpose of the study from the volunteers, at least until the study was completed. After six weeks of movie screenings, the participants filled out a questionnaire on the seventh week.
The result from the survey was very compelling. The porn group reported, on a scale of 1 to 10, much less satisfaction with their sexual partners (3.88 vs 5.47, p < 0.0001), much less satisfaction with their partner's level of sexual curiosity (3.63 vs 5.82, p < 0.0001), and much less importance on faithfulness in a relationship (4.05 vs 6.00, p < 0.0001), than the non-porn group. Additionally, there is no difference between men and women; both are affected the same way by porn. Furthermore, there were no correlation between watching porn and other aspects of happiness that is not sexual related, such as career or financial security.
However, I have a problem with this study. I just finished reading the book Blink: The Art of Thinking without Thinking and one of the things I learned is that our subconscious mind and our conscious mind don't always understand each other. For instance, a group of speed daters were asked to fill out a questionnaire about their ideal mate immediately before, one week after and six months after the dates. The results are quite surprising. After they met someone during the dates, their answers totally changed a week later. Yet after six months, their answers went back to what they were before the date. I wonder if the same thing could be at work here. Immediately after watching porn, our expectations are distorted, as expected. But could it be that the effects are just temporary and given time, the responses to the survey, say six months after watching porn, would be more or less like that of the control group? I think the jury is still out on that one.
In any case, Jenna Jameson, however successful in her career, there is still this profound loneliness about her. I feel kinda sorry that a cool, smart, and beautiful girl like her will probably never find relationships and family life that the rest of us will. Maybe a more interesting study is to look at the psychological impact of pornography on the lives of porn stars...
Posted in Sex as Science, Internet People | no comments
Posted by James
Fri, 08 Jun 2007 09:08:00 GMT
It's been eons since my last Sex as Science entry. Currently, I'm reading a very interesting book titled Sperm Wars by Robin Baker. Baker is one of the first scientist to study sperm competition in humans. In a nutshell, he proposes the theory that most of our reproductive behaviors are products of sperm competition, where sperm from multiple males compete inside the female to fertilize the egg. There is convincing evidence for this. In fact, only 1% of the sperm in a typical ejaculate are fertile. The rest are blockers (which jam up passage ways to prevent other sperm from passing) and killers (which seek out and kill foreign sperm). Using sperm competition as the basis, Baker tries to explain everything from infidelity to masturbation, and from mate selection to homosexuality.
One example is female orgasm. There is great debate on the purpose of female orgasm and why it is so unpredictable. Baker explains that female orgasm achieves mainly two things. One, it sucks up more sperm into the cervix during a very brief time-window around the moment of orgasm. Without an orgasm, 0-50% of the sperm will be uploaded into the cervix. With an orgasm, this number increases to 50-90%. Second, an orgasm changes the constitution of the fluid coming out of the cervix. This creates a filter, which make it more difficult for later arriving sperm to pass. Thus a woman varies the occurrence of orgasm, whether pre, during, or post coitus (or not at all), depending on her body's preferred reproductive strategy. For instance, if her body decides that she doesn't want to conceive, then she is more likely to climax before coitus. She can also bias the outcome of the sperm competition by climaxing during intercourse with the man she prefers to have babies with and not climaxing or climaxing early with others. Which incidentally also explains why women fake orgasms so often.
The book is written in an unusual style. Baker presents a series of vignettes, almost pornographic in nature, followed by a exposition examining the science behind the actions. The advantage is that this is probably the most interesting science writing that most people will ever read. However, much of the science is hidden behind stories that are somewhat distracting.
I have, however, more serious criticism of Baker's work. He presents every behavior in the context of sperm competition, which makes all human actions seem mechanistic. We become nothing but genetic automatons. Many of the scenarios presented in the book are performed by people who are all unconscious of their true motivations. I have philosophical disagreements with this view. People are more than the sum of their genes. We have free will. In Baker's world, infidelity isn't so much willed as it is programmed. Moreover, nowhere does the word love come into play. I believe that love will either enhance or interfere with our abilities to follow an optimum reproductive strategy. I think the affective aspect of human sexual behavior requires much more investigation.
A lot of what Baker wrote makes sense, even though some claims require more scientific evidence. In the end, we're left with the core dilemma, which is not in dispute. Namely, women want to seek men with the best genes to have babies with and want to raise them with men who are stable. Often these two aren't the same. This undercurrent is behind most, if not all, of our reproductive behavior.
Which reminds me; I will definitely add a paternity testing clause to my prenup. I'm a big fan of the trust-but-verify school of thought.
Posted in Sex as Science | 1 comment
Posted by James
Sun, 22 Apr 2007 15:36:00 GMT
I was lazy this morning so I stayed in bed and read a chapter in the book The Red Queen. The core of this chapter explored the causes of male promiscuity and polygamy in human society. We all know that biology predicts that males will be more promiscuous than females due to the simple fact that males benefit more from quantity than females do. Men can sire more offsprings by having sex with more women, but a woman won't necessarily sire more offspring by having sex with more men. The consequences of this is ingrained, to a large extent, in human nature. For example, a study before the AIDS epidemic found that 75% of the gay men in San Francisco had more than 100 partners; the other 25% had more than 1000 partners! More surprisingly, lesbians are completely the opposite. One study showed that most lesbians have less than 10 partners in their entire life. This doesn't say anything about homosexuals in particular but rather about human nature in general. If straight men have access to the amount of sexual availability as gay men, we would be as promiscuous.
But this is all old news to me since I learned it in my biology classes years ago. What was new and interesting to me is the social, anthropological, and historical causes and effects of polygamy. We must look a bit into history to understand our current system of mating behavior. The reason is simple:
[Inside] the skull of a modern city dweller there resides a brain designed for hunting and gathering in small groups on the African savanna.
In another words, our rapid social progress has left our biological body badly outdated.
Our closest cousins, the apes, are highly promiscuous. By contrast, humans are unique among primates because we are mostly monogamous. The reason for this started millions of years ago when human ancestors diverged from the apes and migrated to the savannas from the forests. Food was much more scarce and distributed non-uniformly in savannas. This limited the size of the groups of pre-humans. A good rule of thumb is that mammals tend to be more promiscuous and have harems when the group size is large instead of small. Then when food became rarer still, human ancestors diverged again and we became carnivores; we hunted. In fact, humans are the most carnivorous of all the apes. But the problem is that hunting is much more luck than skill. So men were force to work together and cooperate. No one man had too much power over another in the same tribe, therefore lacked the power to monopolize the women. Thus the roots of our nature is mostly monogamous.
But then came the Agriculture Revolution. Now food can produced close to home and stored, which fundamentally changed society and mating. Some individuals became more powerful than others and didn't need to cooperate with others. Rich and powerful men started to acquire multiple wives. This trend increased as power became more and more concentrated. In all six ancient civilization of Babylon, Egypt, India, China, Aztec and Incan, the emperor had absolute power and harems of hundreds to tens of thousand concubines. Yet the six civilizations are still nominally monogamous, since every emperor had only one queen who is elevated above all of the concubines in status. Later civilizations such as Rome, emperors and the like had plenty of sexual extravagances with women other than their wives (including slave girls).
Today we have come full circle. With the advent of democracy, polygamy in modern society has gone away for the most part. With democracy, no one man has much more power over others as another (at least, in the eyes of the law). Polygamy became untenable since when one man has ten wives, then obviously there are nine men without any. The institutionalization of monogamy isn't for the benefit of the women, since it's more beneficial to be the second wife of a rich man than the first wife of a poor man, but instead it's for the benefit of other men. Society as a whole is more stable with monogamy because a vast number of murders and tribal warfare is over access to women.
However, human nature is what it is. We're neither wholly monogamous nor completely polygamous. We are best described as mostly monogamous with promiscuous tendencies. And I'll end with my favorite passage of the entire chapter:
The best [men] could hope for in the Pleistocene period was one or two faithful wives and a few affairs if their hunting or political skills were especially great. The best they can hope for now is a good-looking younger mistress and a devoted wife who is traded in every decade or so. We're back to square one.
Posted in Sex as Science | 1 comment
Posted by James
Sat, 31 Mar 2007 02:38:00 GMT
Right now I'm reading the excellent book, The Red Queen: Sex and The Evolution of Human Nature by Matt Ridley. I'm done with the first 3 chapters of the book and I'm very eager to share some of the knowledge.
The problem is very fundamental yet the question is deceptively simple. Why sex? The smart-ass answer is "because it feels good", which is true but doesn't really answer the question. The by-product of sex is reproduction. However reproduction can happen many ways, and sex is just one of them. Many species of plants and animals reproduce asexually. For example, some species of reptiles can reproduce via Parthenogensis or female virgin birth. So, we return to our original question. Why sex?
It's actually a lot worse than that. There's a big problem with sex, and that is due to males (most feminists would agree, although for very different reasons). Imagine we have a species that could reproduce two ways, either sexually or asexually. Assume these two variants have the same generation time and the same number of offsprings per generation. The sexual variants need two individuals to reproduce, a male and a female. The asexual variants need only one individual, the female, to achieve the same thing. It doesn't take a genius to see that the asexual variants is twice as productive each and every generation. This means, in only a few generations, the asexual variant will out-breed the sexual variants. Sex it appears is severely disadvantaged. Then how could sex possibly evolve? Even if sex appeared spontaneously due to a chance mutation, how could it ever survive more than a few generations?
There are a lot of different theories. One early hypothesis is the Vicar of Bray, which basically states that sexual species evolve faster than asexual species which allows the former to outcompete the latter in changing environments. But the Vicar of Bray is basically a group selection argument, which has been thoroughly discredited. There are other theories that say sex is favored because it removes deleterious mutations through recombination. Since every individual accumulates genetic mutations, recombination creates offsprings with variable number of these mutations. Some offspring will have very few (or none) of the mutations from the parents while others will be a dumpster for these mutations (which they often die early). Without recombination (or sex), the offsprings will have at least as many mutations as their parents, which is the essence of Muller's rachet. However, experiments and simulations indicates that the mutations rates must be very high for this to overpower the two-fold reproductive advantage of asex. In short, the theory looks good but is unsupported by empirical evidence.
The most promising theory to answer our question is the Red Queen hypothesis, named after the red queen in Through the Looking Glass by Lewis Carroll, who has to run as fast as she can to stay in the same place. In a nutshell, what kills organisms is most likely not the physical environment, but rather, other organisms, specifically parasites. Sex therefore is the ultimate defense against parasites in this eternal arms race. Parasites have short generation times, therefore they can evolve rapidly to accommodate the host's defense mechanisms. If the offspring is identical to its parent, then it is basically screwed. As soon as it's born, the parasite will already "know" how to attack it. Therefore, the best strategy is to have the offspring to be different from the parents so the parasites have to start over with the new generation. This might sound a little counterintuitive. The best part of life is due to parasites? But incredibly this is backed up by loads of empirical evidence.
But the debate is by no means over. Recently a paper in PLoS Biology has reaffirmed the Red Queen hypothesis in spite of some new doubts. I expect as more evidence is gathered, we'll get a much more complete picture in the near future.
But the book doesn't stop there. There are tons of other interesting, yet fundamental questions about sex. Why are there (most of the time) only two genders? How do male and female differ in their evolutionary strategies? Why polygamy? Why monogamy? I'm really looking forward to reading the rest of the book. The answers may appear in some future Sex as Science posts.
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Posted by James
Wed, 07 Mar 2007 01:55:00 GMT
Has it really been a month since my last Sex as Science post? A few weeks ago, someone reminded me that it was Mardi Gras. Having moved away from the South sometime ago, I didn't even know Mardi Gras was upon us. And sometime ago, I found a very interesting paper entitled A Theory-Based Approach to Understanding Sexual Behavior at Mardi Gras published just last year. The corresponding author, Michael Reece, is from Indiana University, Bloomington which has a long history of cutting edge sex research dating back to the days of Alfred Kinsey.
Now, on to the research paper. It is widely known that during Mardi Gras, casual sex flows almost as readily as cheap alcohol. The researchers wanted to understand the process by which these uninhibited behaviors are elicited and create a model to predict these behaviors. Increased propensity for casual sex is not confined only to Mardi Gras, but also occurs during any time when people go on holiday such as during spring break or schoolies week. The authors attempted to create a model using the Triandis theory of interpersonal behavior (TIB) to explain how these behaviors arise. I don't know much about TIB, so I will quote directly from the paper:
At the first level, [Triandis] theorizes about how personal characteristics (gender, race and social class) and prior experiences shape personal attitudes, beliefs and social norms related to behavior. At the second level, Triandis explains how cognition, affect, social determinants, and personal normative beliefs influence the formation of intentions with regard to a specific behavior. Finally, at the third level, Triandis proposes that intentions regarding the behavior, prior experience with the behavior, and situational conditions predict whether or not the individual will engage in the behavior.
In a nutshell, TIB says prior experience and upbringing forms personal values and personal values plus social surrounding shapes intentions for some action and when intentions and environment conditions match, the action is performed. From this model, the researchers created a series of questions which were asked to a (not so random) sample of 300 Mardi Gras participants (180 men, 120 women).
The results are quite interesting. For starters, men and women had different intentions going into Mardi Gras. For instance, 45% of the men expected to engage in oral sex with someone they meet at Mardi Gras, 42% expected vaginal sex, and 19% expected anal sex. Whereas for women, the percentages are 16%, 12% and 5% respectively. However there are no gender differences in the actual occurrence of sex. In fact, 16% of men and women engaged in oral sex, 32% engaged in vaginal sex and 6% engaged in anal sex. Therefore it seems that men tend to overestimated their sexual activites during Mardi Gras while women underestimated theirs.
The main point of the paper is using TIB to model behavior. To do this they correlated survey scores with actual behavior using the Pearson correlation coefficient. It turns out cognitive beliefs and subjective social norms predicted intention formation only for the men and not the women. But once intentions are formed, the TIB predicted quite well how both men and women behaved during Mardi Gras, at least for some forms of sex acts.
From this paper it seems that TIB is at least somewhat effective as a model. But this model may be too simplistic to capture how women make sexual decisions. In any case, if you find yourself at Mardi Gras or spring break and looking for a little action, there's a few key points to keep in mind. The likelihood of sex is correlated with a) intentions to engage in sexual activity, b) previous sexual experience, c) situational conditions, and d) the perception that your friends are doing it too.
I hope that was understandable...
Posted in Sex as Science | 3 comments
Posted by James
Sat, 03 Feb 2007 19:33:00 GMT
It's been a long time since my last Sex as Science post. So today, in the spirit of all is fair in love and war, I'm going to talk about human mate poaching. That's right folks! This is about stealing someone away from an existing relationship. This work was done by a bunch of evolutionary psychologists, and one of the authors is David Buss of UT Austin. David is the foremost authority on evolutionary psychology of sex and attraction, so don't be surprised if you see more of his work in later posts.
This particular paper, Human Mate Poaching: Tactics and Temptations for Infiltrating Existing Mateships (pdf) was published in 2001 in the Journal of Personality and Social Psychology. It involves four different survey experiments gauging four different aspects of mate poaching: frequency of mate poaching, costs and benefits of mate poaching, tactics of mate poaching and mate poaching under different relationship contexts. The authors define human mate poaching as attracting someone who is already in a romantic relationship. There are two temporal varieties of poaching: the short-term and the long term. The short-term poaching refers to attracting someone away for a fling, where as long-term poaching refers to the same act but with a goal of creating a long term relationship or even marriage.
In the first experiment, they found that over 50% of the men and women have tried to poach someone who is already in a relationship. Although very few of them attempts this regularly. However, over 85% reports that they themselves have been the target of poaching attempts. To me, this poaching gap is probably because some of these perceived poaching attempts were misinterpreted. Also the experiment suggests that for women to poach a man, the success rate is in excess of 40% and for men to poach a woman, the success rate is somewhat less, at a bit over 30%. Additionally, the older the man is, the easier it is for a woman to poach him; the opposite is true for a woman. Most surprisingly, older women are more likely to frequently employ poaching as a means to secure a long-term mate.
The second experiment attempted to ascertain the reasons for poaching. Since poaching is generally a less effective strategy and entails more risk, there logically has to be some good reasons for engaging in this type of behavior. It turns out that men poach to obtain a more attractive mate, since more attractive females are more likely to be already in an relationship. Women, on the other hand, poach to find someone with resources and a willingness to invest those resources, especially in the short-term. This experiment also identified some costs to poaching such as: future infidelity, guilt, deception, dating isolation, and family rejection.
The next study is the most interesting. It looked at various tactics of how mate poaching can be accomplished. It turns out for a man, acting more dominant (macho) isn't as effective as demonstrating resources or acting generous for short-term poaching and creating emotional connection and manipulating the emotional commitments of his rival for long-term poaching. For a woman, the most effective strategy is to suggest easy sexual access, or manipulate the sexual commitments of her rival. Even more interesting, suggesting easy sexual access is more effective than providing or arranging easy sexual access for female poachers. Also, for female poachers, the outright rupturing of the existing relationship is a more effective tactic than for male poachers. Overall, women are better poachers than men.
Lastly, the authors looked at certain qualities of the target relationship and poaching effectiveness. Some very interesting results were found. For example, if a female poacher tries the tactic of providing easy sexual access, it will be less effective on men who are married compared to men who are dating. Also, for a male poacher, the tactic of demonstrating resources is more effective on a woman who is just beginning a relationship compared to a woman who is highly committed to a relationship. And if you're a woman trying to poach a man away from a long distance relationship, the most effective strategy seems to be suggest to him that his mate is no longer sexually committed him.
Over all, this study is very interesting and is one of the first to look at human mate poaching from the perspective of the one doing the poaching. I generally dislike the methodology of surveys, because I'm a big fan of experiements. However, I recognize that it would be difficult, if not impossible to perform experiments given the nature of this subject. Also I would just like to briefly comment on the ethics of poaching. Personally I believe that poaching is a legitimate tactic in human relationships. Everyone has a thing called free will, so the poached is just as responsible as the poacher. Of course, I'm not suggesting that everyone go around trying poaching just for fun. But, in love, as in war, sometimes we have to do things that we're not proud of in order to achieve a more noble objective. In this case, if a better relationship is created as an result of poaching, then who are we to judge?
Posted in Sex as Science | 5 comments
Posted by James
Mon, 18 Dec 2006 16:08:00 GMT
It's time for another installment of Sex as Science and today I will be discussing a very fascinating study on the effects of age on sperm quality.
This particular paper entitled Quantitative effects of male age on sperm motion was published in June of this year, by a bunch of people at the Lawrence Livermore National Labs and the School of Public Health at UC Berkeley. I for one had no idea that the LLNL did this type of research. For this study, they used 90 people, ranging from 22 years of age all the way to 80 years of age (a shoo-in for the "coolest grandpa of the year"). All were either current or retired employees of LLBL. The researchers were mainly interested in quantifying sperm quality as a function of age, so they needed to somehow formulate a measure of sperm quality. To this end, they used a technique called CASA (computer assisted semen analysis). Basically, they put drops of sperm samples on a microscope slide, placed it under a computer controlled microscope and had the computer analyze the samples according to 14 different quantitative measures. Then they performed a linear regression of these measures against age to produce their conclusions.
What they found was that 6 out of the 14 measures were negatively correlated with age. Motility (MOT, defined as the percentage of sperm that moved) decreased 0.8% per year. Additionally, sperm with rapid motility (RAP, defined as the percentage of sperm that moved faster than 25 μm/s) decreased 0.4% per year and progressive motility (PRO, defined as percent of sperm that is rapid and traveled more than 80% straight) decreased 0.9% per year. All three of these measures had a p-value of less than 0.0001 (ie. very strongly correlated with age). Additionally they found that average path velocity (VAP), straight line velocity (VSL) and linearity (LIN, which is a ratio of straight line velocity to curvilinear velocity) of sperm also decreased with age. Surprisingly, the study found no correlation between total sperm count or sperm concentration with age.
In the discussion, they talked about the effects of these six measures:
MOT, RAP and PRO have been associated with decreased pregnancy rates and longer time to pregnancy in partners of older men. VSL, LIN, and VAP have been correlated with fertilization rates in vivo and may be bioindicators of the fertilizing ability of human sperm.
Also they gave an example which essentially says that the sperm of a healthy 55 year-old male travels 10% less distance at 9% less velocity than that of a healthy 25 year-old.
The reason for the decreased sperm motion with age is currently not well known. However, some studies have shown that the ingestion of antioxidants may mitigate the effects of age on sperm motility. Unlike fertility in women, the decrease in sperm quality in men is uniform with no cut-off point. However, like women, the best time to have children (physically speaking) is when we're young. Because -0.8% per year waits for no one.
Posted in Sex as Science | 3 comments
Posted by James
Wed, 29 Nov 2006 00:33:00 GMT
I hadn't planned on writing another Sex as Science column so soon, but today I came across this news article that got me really excited. Basically, some British scientists are working on a non-hormonal male contraceptive pill that works by preventing the ejection of sperm, but doesn't otherwise interfere with normal sexual activities. However, since I don't trust the mainstream media to write accurately about science, I did some research of my own.
It turns out, the key to preventing the ejection of sperm is to inhibit the smooth muscle cells in the vas deferens. In case you're not familiar, the vas deferens is a tube that connects the epididymis with the prostate gland. More commonly, it is the tube that gets cut in a vasectomy (hence the name of the procedure... ah... it's all coming together). The smooth muscle cells in the vas deferens has two types of receptors. One is the P2X receptor which fires in response to ATP and the other is the α-adrenoreceptor which fires in response to noradrenaline (also known as norepinephrine). Apparently both chemicals are released during orgasm and it appears both are needed to stimulate firing of the smooth muscle cells (I'm still a little vague on why that is). I learned all of this by reading two papers I found on the web.
The first paper is about a study done on the P2X1 receptor in mice. The researchers created a strain of mice that had the P2X1 gene knocked out, and the ones with homogeneous (-/-) knockout showed a 90.4% reduction in fecundity. Using various techniques the researchers demonstrated that these mutant mice were healthy, had normal sperm count, and had normal volume of ejaculate. The only difference was that sperm wasn't being conducted out of the vas deferens.
The second paper was written by the same team that was featured in the MSNBC article. Unfortunately, this paper is a lot less readable than the first one. In this case, the research was done on the α1-adrenoreceptor in human vas deferens. However, the study was performed on vas deferens tissue extracted from men, not in a clinical trial setting. Basically they tried a bunch of drugs and showed the effects of these different drugs on different types of the vas deferens muscle tissue.
Extrapolating to the news article, it seems they are beginning phase I clinical trials currently with the α1-adrenoreceptor blockers and are expecting the drug (if it passes the necessary hurdles) to be available in 5 years. However, the article claims that with this pill, men will experience orgasm as usual, except it will be with "dry ejaculation" (or "shooting blanks" as it is known on the streets). I very much doubt that the orgasm will be "dry" since semen is produced separately in the seminal vesicle just before the prostate gland and takes a different route from sperm. I believe (although not positive) that the ejaculate will be the same, just without sperm (kind of like what happens after vasectomy).
The most exciting aspect of this type of male contraceptive is that it's not hormone based. You really don't want to be taking hormones just to control your sperm production, it's just not natural for a man and can have other unintended consequences (after all, hormones are used for many different purposes in the body). Also this pill is great because it will work like Viagra: you can take it 30 minutes before sex, and the effects wear off after a few hours. Its effectiveness is expected to be about 90%, which is less than that of condoms, but roughly in the ballpark of diaphragms or contraceptive sponges (with spermicide). Lastly it's non-invasive. There are other methods that require injecting something into the vas deferens (uh... no thanks). So, this sounds like a miracle pill and I'm totally trying it when and if it become available.
Unfortunately, like most other contraceptives, this pill will not prevent against STDs. So it's definitely not appropriate for sexual encounters between strangers. However, if you're in a stable long term relationship, this will probably rock your world.
Posted in Sex as Science, The Best Of | 4 comments
Posted by James
Fri, 24 Nov 2006 14:36:00 GMT
On this wonderful day after Thanksgiving, I'm going to continue my Sex as Science column with two articles I found on PLoS Medicine a few months ago. The articles were part of a special on Disease Mongering, and in case you aren't familiar with the term, disease mongering refers to the phenomenon of trying to convince essentially well people that they are sick, or slightly sick people that they are very ill.
The first article explores how Pfizer redefined erectile dysfunction (ED) and subsequently made billions on it. It was funny because before Viagra came along, ED wasn't that big of a problem. What Pfizer did (somewhat brilliantly) was that they made ED into a big deal.
First, they claimed that more than 50% of men over 40 had problems maintaining an erection. Now I don't know about you, but that number scares me... if it were true. Pfizer never did cite the source of the data, and studies by other groups showed that only 18% of men 50-59 had problems achieving or maintaining an erection. In fact a Dutch study found only 1% of men 50-65 had a complete inability to achieve an erection. The second thing Pfizer did was they claimed that Viagra works for 80% of the men taking it. But one must read the fine print. The claim is that 80% of the men taking Viagra had an "improved erection" (whatever that means), but studies have shown that only 50% to 60% of the men were able to achieve successful intercourse. So it really depends on what's important, achieving a better erection (which is subjective) or have successful intercourse and orgasm. And lastly, Pfizer did an awesome job marketing ED. At first, they had Bob Dole (an old man) as spokesman for Viagra. But more recently, Pfizer hired much younger men, like former baseball player Rafael Palmeiro (39 years old) as spokesman. This is obviously intended to drive the message home that ED happens to (nearly) everyone, especially the young and healthy.
As a result, ED is no longer a disease, but a (perceived) lifestyle problem. Pfizer's success can be clearly seen as other pharmaceutical companies have already came out with their own ED drugs to compete. With the amount of R&D spent on ED, one would think that perhaps the survival of the human race is hanging on the balance because we (as a species) can no longer get it up.
But ED is only one side of this coin. The second article, talks about FSD (female sexual dysfunction). In fact, FSD was only coined in the late 1990s and it was promoted by a combination of the media, shoddy research, and of course, big pharma. The funny thing is, no one can really agree on what FSD is, let alone how to diagnose or treat it.
Nevertheless, as soon as Viagra came out, researchers tried it on women. Even though there is no evidence that Viagra has any effect on women, the perception remains that it must work (because it's a miracle drug). Also, Proctor and Gamble tried to promote the testosterone patch for women (which again, has no demonstrated effect), and the FDA voted unanimously to not approve it for use. However, this doesn't mean people don't use it. In fact, about 20% of the testosterone products approved for men are being prescribed off-label to women (off-label prescription is when the doctor prescribes a drug to a patient for something the drug is not designed or intended for; it is a common practice, but carries enormous risk, for both the patient and the doctor).
The conclusion I reached after reading these two articles is that because most people are ignorant about the science behind sex, pharmaceutical companies were able to easily drive these questionable and false ideas into people's heads and reap billions in profits. Sure, everyone wants to have a satisfying sex life, but we must understand that normal is different for everyone. And in the end, the more you know about yourself (sex or otherwise), the happier you will become.
Posted in Sex as Science | 2 comments
Posted by James
Wed, 08 Nov 2006 01:58:00 GMT
I've become really interested in sex. And no... it's not because I just discovered the joys of sex or that I'm a sick twisted pervert (your opinion not needed). No no, on the contrary, I've become interested in studying sex from a scientific point of view. For humans, sex is this mysterious act shrowded in taboo and intrigue. Most do it; but most don't understand it. In fact, there are many aspects of sex that no one understands, which makes it a frontier (and fun) subject for scientific exploration. And to do my part, I'm start this new column in my blog which I call Sex as Science. In it I will explore sex from all branches of science: from molecular biology to psychology, from biochemistry to evolution, and from game theory to epidemiology. I promise to leave no stones unturned. I think you will enjoy reading this, and probably learn a few fun facts. Besides, I have to do something with my biology degree...
Today I want to ask (and answer) two questions that seems quite different but turns out to be very much related. The first question is: why do you lose interest in sex after sex? And the second: how much better is sex than masturbation?
The answer to the first question can be found in this paper (pdf) published in 2001 in the journal Psychoneuroendocrinology (now say that 5 times). The secret lies in two chemicals dopamine and prolactin. Dopamine is more commonly known as the pleasure (or reward) neurotransmitter. It is produced in the hypothalamus and released in response to pleasure or even the anticipation of pleasure (incidentally, dopamine is the same chemical that makes gamblers double down and drug addicts shoot heroin). Prolactin on the other hand is a hormone produced in the pituitary gland and is most commonly known as the chemical that induces milk production in women (hence the name: pro-lactin). However like all chemicals in the body, prolactin serves multiple purposes. In this case prolactin suppresses dopamine in a negative feedback loop. In simplified terms, dopamine is responsible for sexual arousal, and during sex its level in the body rises. This triggers a corresponding increase in prolactin levels (in an attempt to check the rise in dopamine) and this peaks during orgasm. Consequently the elevated levels of prolactin post-orgasm inhibit the effects of dopamine, hence our desire to have sex disappears. In fact this elevated level of prolactin remains in the blood up to an hour after orgasm. The interesting part of this is that this dopamine-prolactin negative feedback loop seems to be specific to orgasmic sex, and other events that causes a rise in dopamine does not (as far as we know) induce an increase in prolactin.
Now knowing this, we could answer the second question. This was in fact done by the same group in another paper (pdf) published in 2006. Since we know that a rise in prolactin occurs after orgasm, we could ask the question how much difference (if any) can we see in the post-orgasmic levels of prolactin after sex versus after masturbation. So the researchers designed a very interesting experiment (I encourage you to read about the methodology in the paper) and answered this exact question. As it turns out, the prolactin levels after sex is between 4 to 5 times of the prolactin levels after masturbation, in both men and women. Taking prolactin levels as a proxy to satisfaction, we can say that sex is about 4 to 5 times better than masturbation. Cool huh?
So the bottom line is: prolactin == good!
Posted in Sex as Science, The Best Of | 5 comments
