Women to stop liking Sean Connery?

Boyish good looks -
the next generation of sexy?

Men like Mike Rowe on the outs?

ResearchBlogging.orgI couldn't help but notice that a new study has come out about the behavioral effects of hormonal contraception. It's all over the science news sites. With titles ranging from the conservative "Pill May Change Attraction" to the bolder "Taking the pill for past 40 years 'has put women off masculine men'"and "The pill 'gives women a taste for boyish men like Zac Efron'," this new publication has swept the media outlets by storm. This idea that birth control might have behavioral side effects isn't new, even I've mentioned this before, as a side note on another study's findings. But the strong tone and conclusions in this review paper seem to have caught the media's attention, causing Grizzly Adams impersonators everywhere to fear that they're soon to be cast out of their lovers' bedrooms in favor of DiCaprio-esque alternatives.

Calm down, manly men. It's just like how the media always starts raving about how scientists have found a "missing link" every time there's a new fossil species identified - mention sex or relationships in a paper, and it's bound to get noticed. And just like the constant "missing link" hype, the whirlwhind response to this paper is unfounded and ridiculous.

Don't get me wrong - I love a good paper about behavior and hormones. But a non-systematic review paper has a lot of holes in it, and this one is no exception.

In the paper, the authors state that "there is emerging evidence that the use of the pill by women can disrupt: (i) the variation in mate preferences across their menstrual cycle; (ii) their attractiveness to men; and (iii) their ability to compete with normally cycling women for access to mates" and that there are "consequences of pill-induced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes."

Let me start by explaining the paper's premise. It's somewhat established scientifically that certain traits that women find attractive - like "manliness" - can vary over the menstrual cycle. When a woman is most fertile, she's more strongly attracted to more masculine men. There's some suggestion that this is because while she may not be able to marry the sexiest, most genetically spectacular man alive, she can sleep with him behind her mate's back when she's highly fertile and get a genetically fantastic kid while still keeping the loser hubby around to take care of him. In turn, scientists have shown that women are sexiest to men when they're most fertile - the theory being that if men sleep with a woman when she is most likely to get pregnant, then they're most likely to pass on their genes. All of these shifts in attractiveness are completely unconscious, so we don't know that we're changing how we see each other over a monthly cycle.

The Culprit?

Hormonal birth controls change the hormones in a woman's cycle. They convince her body that she's pregnant, thus preventing her from going through ovulation-induced changes into that 'high fertility' state. Logically following, this change in hormones might shift how she views men and how men view her, because she's never entering that body phase where all this change in attraction occurs.

Then, the paper's authors conclude, it's likely that the women taking the pill are shifting society's opinion of men, steering towards less masculinity. They're changing the rules, making feminine men more attractive and thus more likely to mate, which they say could have drastic consequences. Since manly men are supposed to contain the 'better' genes, a shift in mate choice could have reproductive repercussions. As one of the co-authors, Dr Virpi Lumma, is quoted as saying: "The ultimate outstanding evolutionary question concerns whether the use of oral contraceptives when making mating decisions can have long-term consequences on the ability of couples to reproduce."

Even on the small scale, they warn that birth control might be dooming relationships, because women are likely to be off birth control before a relationship, then meet someone, and go on it. Beforehand, the women had 'high fertility' attractions, but after, their tastes change. Even if it's not dooming the masses, it could be a major contributing factor to the rising divorce rate and general relationship woes.

It sounds very logical, but there are gaping holes that the journalists and even the study authors completely ignore.

Firstly, it's important to point out that this is a non-systemic review. A non-systemic review is one that doesn't describe the methods used to choose the papers which are included in it. The authors say that 75% of the studies performed in the past decade support their conclusions. But how did they choose the 72 studies included in their review? How exhaustive was their search? Without explaining these methods, it's entirely possible that the review is biased, focusing on research which supports the writers' preformed conclusion.

Small, non-random samples aren't fit
mathematically to be expanded to populations

But even assuming that the choices were comprehensive when it comes to the literature, there are flaws in those, too. Most of these studies have incredibly low, non-random sample sizes (i.e. <100 college students who want extra credit in their psych class). When talking about large-scale changes which affect populations, such small sizes that aren't randomly selected are poor choices. After all, would you say that the overall political views of the country are the same as the population of one town in Texas? The larger the extrapolation of the data, the larger and more random the sampled set needs to be to be statistically relevant.

Furthermore, when comparing women who are on the pill to those who are not, the treatment group the women are in isn't double blind or random. The two groups are self selected - aka women who are on the pill already versus those that aren't. There is no control, no group that takes a placebo or, at least, goes from not taking the pill to taking it (with one exception - kind of. I'll explain in a minute). No clinical studies into side effects - like those done on various pharmaceuticals - would be tolerated without these kinds of controls.

It goes back to the underlying scientific question of the chicken or the egg. It's possible that taking birth control affects one's mate preferences. It's also possible that those with certain mate preferences are more interested in taking birth control, particularly those interested in the pill over other contraceptive methods like condoms. The studies examined in this review lack the power and structure to determine the difference. After all, studies have shown that there are differences in contraceptive use between political, religious, and age groups. Is it not entirely likely that underlying factor might stimulate a woman to be attracted to 'boyish' men and take birth control, like her religious preferences? The only study covered in the review which did, at least, compare women before and after taking the pill, did not randomly select women for each group. The women elected to take the pill or not, which means it does not rule out all of these issues.

Furthermore, among their logical conclusions, the authors suggest that taking the pill after starting a relationship may affect relationship satisfaction because a woman might change her mind about what she finds attractive. Call me a scientist, but can I have some data? This one ought to be easy to look at! Why speculate so broadly without any kind of data to back it up?

The authors do note that their conclusions are 'speculative,' but it seems the mainstream media has overlooked this portion of the paper. The majority of their conclusions are evolutionary speculations, not scientifically supported theories. And there is danger in trying to see everything from an evolutionary perspective. Evolution is a complex combination of selection, random change, and genetic shifts.

Don't panic, Jackie.
Your rugged good looks won't
keep women from wanting you

Not everything in the world has a concrete, easy to understand and logical reason for why it came out that way. There are jumps and changes that are under little to no selection at all, and the evolutionary 'reasons' for even those traits that are under natural or sexual selection can be hard to decipher.

While this paper is good discussion fodder, it's conclusions and theories should be taken with a very large grain of salt. The science in it is very interesting, however, it's hardly conclusive, and as journalists and reporters of science we need to be more careful in how we talk about science to the public. I'm fairly certain that rugged, manly men still can make women swoon, and that we're not all genetically doomed from birth control (I'm even more positive of this while looking for images for this post, and flipping through pages and pages of Hugh Jackman).

Now, the potential genetic doom of the fish and aquatic creatures who are getting dosed with high levels of these hormones from untreated sewage runoff, that's a different story... for a different day.

Alexandra Alvergne, & Virpi Lummaa (2009). Does the contraceptive pill alter mate choice in humans? Trends in Ecology and Evolution : 10.1016/j.tree.2009.08.003


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