Gene Expression

Does the pill matter?

Eric Michael Johnson has a post up, Does Taking Birth Control Alter Women’s Sexual Choices?, where he surveys a new paper,Does the contraceptive pill alter mate choice in humans?. Eric notes:

The concern of the researchers is that a woman who gets involved with a guy while on the pill might find that she’s no longer compatible with him once she stops later on in the relationship. Imagine waking up next to your boyfriend, or even your husband, one morning only to discover that you’re just not that into him. While female comedians make such scenarios commonplace in their stand-up routines, Alvergne and Lummaa suggest it could be a reality faced by the modern woman.

There are lots of issues in relationships. Here’s a chart of divorce rates from 1940 to 2000.



  1. #1 Meng Bomin
    October 12, 2009

    Could you at least tell us what the legend says in the chart. The scale makes the text nearly unreadable and while I think that I’ve deciphered that the red line represents absolute number of divorces and the blue line represents the rate, it would be nice if there were a readable version.

  2. #2 MRW
    October 12, 2009

    Any help on the figure legend? I have no idea what it says.

  3. #3 Jordi
    October 12, 2009

    What do the lines represent? The legend is unreadable.

  4. #4 Katharine
    October 12, 2009

    What I am concerned about is some people’s propensity to use this as ‘proof’ (which it is not) for their absurd notion that all birth control somehow is bad.

    There are non-hormonal methods of birth control, such as IUDs, condoms, diaphragms, vasectomy, and tubal ligations/Essure. In addition, how much of this chart is accounted for by hormonal change and how much of this chart is accounted for by things such as some idiot divorcing his wife because he finds out she’s on birth control or some other absurdity? I know there’s a pretty good case for hormonal birth control interfering with these things, and I agree that it does; at the same time, I am quite wary about how some individuals will use this data.

  5. #5 EMJ
    October 12, 2009

    What does the legend say? It’s too small for me to read what the two variables are.

  6. #6 razib
    October 12, 2009

    red – divorces & annulments in 1,000s
    blue – divorce & annulment rate for women over 15, in 100,000s

  7. #7 Jesse
    October 12, 2009

    The whole post completely ignores other developments in the legal world:

    1. “No fault” divorce, which was not common until the mid-60s and 70s in many states. It means you don’t have to prove someone was sleeping around or something.

    2. Expansion of women’s property rights. There were several court decisions in the 50s ad 60s that made it much easier for women to divorce and not lose everything, as well as changes in child custody. To put it in perspective, pre WW II if a man asked for a divorce the woman basically was left with nothing.

    3. Social stigma. Greatly reduced in more recent years.

    4. Note the rate of divorce is flat after 1980. That would suggest at a minimum that with no fault divorce, and greater access to the legal system for women, there is a “natural” rate for it — that is, absent all the stuff that kept people — basically women — married before, there’s a certain built-in probability your marriage will fail. It makes sense — why should the odds of finding the perfect person for you be any better than 50-50?

  8. #8 razib
    October 12, 2009

    jesse, i don’t think the pill had much of a causal effect through *this* particular mechanism on divorce rates. please try not to be a mind reader.

  9. #9 EMJ
    October 12, 2009

    And why did you think it was relevant to add this to the issues I was raising? Katharine and Jesse’s assumption that you were making a causal link between birth control and divorce rates is understandable. Why don’t you clarify your reasoning.

  10. #10 razib
    October 13, 2009

    eric, jessie made some of the points. shorter: macrosocial relevance of a lot of this research about sexual preferences are on the margins. i quoted a section which repeats some of the concerns of researchers in this general area. i think these concerns are relatively trivial in relation to other points. and yet the past week has seen my google reader which has alerts for particular queries (e.g., “genetics evolution”) with really alarmist headlines about the pill (albeit, mostly british newspapers). more concretely

    1) the face preference isn’t the only effect of the pill. the psychological and physical changes vary from woman to woman, and some of the changes are of large effect.

    2) in the age of ubiquitous medication for even minor ailments there are all sorts of likely psychological effects which interfere with relationships (e.g., many non-psychotropic drugs, like cholesterol medication, have a psychological side-effect in a minority of patients).

    3) conventional social science parameters are huge considerations which probably dwarf these sorts of biosocial dynamics (including MHC) in effect size.

    the last makes me wonder as to the evolutionary stories around these results.

  11. #11 toto
    October 13, 2009

    WTH is that divorce peak in 1945?…

    Also, divorce rates seem to plateau after 1980. But is it a real stabilisation, or is it just a consequence of the fact that people marry less in the first place?

  12. #12 razib
    October 13, 2009

    a little war in the service of making sure that the british don’t speak german again 🙂

  13. #13 yogi-one
    October 13, 2009

    Imagine waking up next to your boyfriend, or even your husband, one morning only to discover that you’re just not that into him.

    This goes for men, too, believe me.

    It would be interesting to explore the idea further if the post-1980 rate is a natural base rate for human society. This would be very hard to do however, given that human societies are complex and so culturally variable that finding a baseline society for a control would itself be a highly difficult task. All kinds of cultural mores would interfere with the natural rate, not to mention economic factors, and these would somehow have to be corrected for.
    The control and regulation of marriage is a primary feature of most societies. Finding one where marriage was sinply allowed to evolve on its own without institutional interference (such as from religion) I think would be next to impossible.

  14. #14 Jesse
    October 13, 2009

    razib, the way you placed the chart, right after the text, makes it look like you are drawing some kind of causal relationship. I am not a mind reader, but the error on my part is I think, understandable.

    toto – the divorce rate climbed after 1945 in part as a result of marriages during the war that didn’t fly, and a gigantic (assuming this is the US) economic upheaval as all those soldiers came home.

    also he stabilization of rates would be independent of the number of people marrying. It’s measured per 1,000 people, not as an absolute number.

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