Wednesday, April 6, 2011

If I objectify you, will it make you feel bad enough to objectify yourself? On shopping, sexiness and hormones.

Found here.
When I was younger, periods were not a fun time, and I was plagued with dysmenorrhea, which is a fancy term for really bad cramps. In high school, I would often take 1000 mg of ibuprofen every four hours to alleviate symptoms to get through all my classes, band, sports practice, and homework (what, it took you this long to realize I was, and am, a dork?).

After having my daughter in 2008, and the thirteen months of lactational amenorrhea that followed it (lactational amenorrhea means absence of periods due to lactation), my periods resumed. Pain during my periods has almost totally ceased, but I have noticed more cycle-related variation in emotion. In particular, my patience and tolerance for rude behavior, and my tendency to cry sentimentally at even the lamest greeting card, skyrocket in my premenstrual phase. I already have low tolerance for rudeness, and I already cry easily. But something about progesterone decline -- which is a normal process towards the end of ovulatory cycles -- seems to make it harder for me to repress these behaviors in order to fit in culturally with those around me.

I tell this to you to say, I don't doubt that hormones, and hormonal variation through the cycle, plays some role in variation in female behavior and emotion. And I find this kind of work inherently interesting. I hate to repeat myself, but you will find echoes of my structural and methodological concerns with evolutionary psychology in this post as well.

* * *

Durante et al (2011) observe that women spend more money on their appearance than men, and claim that this sex difference is cross-culturally consistent (I wonder, is this consistent across cultures without money?). In order to understand this sex difference, they wish to see whether spending or shopping behavior is dependent on cycle phase. Therefore the authors hypothesize that women choose sexier clothing during ovulation -- "even if the women themselves are not consciously aware of this biological fact" (Durante et al 2011: 922), a problematic turn of phase if I ever saw one, but I'll get to that later. They also consider the effects of priming a shopping woman with images of attractive women and hypothesize there is a greater effect of this priming on high-fertility women.


The participants were female undergraduates and were compensated with course credit or money. The authors claim the participants had no idea the study had anything to do with the menstrual cycle, but the participants had to use LH strips at midcycle to see when she was ovulating (this is a urine test to check for a luteinizing hormone peak, which comes before ovulation).

Here's the important part, for me:
"The first urine test was scheduled 2 days before the expected day of ovulation. If an LH surge was not detected, women came back each day until an LH surge was detected or six tests had been completed, whichever came first" (Durante et al 2011: 924).
Here are my questions: what is 2 days before the expected day of ovulation? The follicular phase -- that's from menstruation to ovulation -- is the most variable phase of the menstrual cycle (Fehring et al. 2006; Lenton et al. 1984). I wonder how many ovulations they missed because of this. Perhaps even worse, how many participants had six LH tests and didn't have a detectable LH surge? It sounds like they were included in the project. But, they either ovulated before the authors started testing, or they had an anovulatory cycle. That means the authors were including participants in their study that weren't ovulating... in a study of behavior during ovulation.

Participants viewed a made-up shopping website on a high-fertility (near the LH surge) and low-fertility (about eight days later) day, where they had to select ten items they would like to buy that day. They were randomized into two groups: one shown a site featuring casual clothes, the other featuring clothes and accessories. The clothing on these made-up sites were "pretested to be sexy" (Durante et al 2011: 925). While that is a phrase I never expected to write on this blog, the separate validation they did to determine sexy versus nonsexy clothing seems fine.

Hypothesis 1: Near ovulation, women should be more likely to choose sexier and revealing clothing and other fashion items rather than items that are less revealing and sexy (Durante et al 2011: 923).
Women chose a greater percentage of sexy clothing and accessory items near ovulation: 59.8% ± 21.6 during ovulation, 51.3% ± 22.4 during low fertility. This was a statistically significant difference, but they did a repeated measures ANOVA, and I don't understand why they didn't do a paired t-test. Further, statistically significant or not, I question how meaningful it is when the averages are so close and the standard deviations almost completely overlap.
H2: Ovulation should lead women to be especially likely to choose sexier products when women are primed to compare themselves to attractive female rivals (Durante et al 2011: 924).

H3: There should be no differences in product choice between ovulating and nonovulating women when women are primed with unattractive women or men (Durante et al 2011: 924).
Follow-up studies primed sub-sets of participants (so a different cohort, same recruitment methods as above) to think about 1) attractive local women, 2) unattractive local women, 3) attractive local men, 4) unattractive local men. They did this by showing photographs of people who they claimed to be local and asking participants to rate their attractiveness.

When primed with attractive women, the percentages of sexy items chosen were 62.7% for ovulating women and 38.2% for low fertility women (I could not find standard deviations for these values so have no idea how much the two groups overlap). Priming with unattractive women, attractive men, or unattractive men produced no significant difference between low and high fertility women.
H4: Ovulation should lead women to choose sexier products when primed to think about local attractive women who constitute potential direct rivals. However, ovulation should not influence product choice when women are primed to think about women from distant locations because such women do not constitute direct rivals (Durante et al 2011: 924).
The authors used a different method for assessing fertility this time; they asked women their normal menstrual cycle length and counted back from menses to estimate when ovulation would be. So AGAIN, we don't know how many women actually ovulated in this study, and we don't know whether a significant portion of women were then grouped in the high-fertility group who shouldn't have been.

This study is like the previous one in terms of photo priming, but this time the photos were said to be local or distant, and were of women only (so the four groups were local attractive, local unattractive, distant attractive, distant unattractive).

The authors claimed that the relationship between fertility, photo attractiveness and location was "marginally significant," but the p-value was 0.09. That is, in fact, not significant, as significance is generally only considered under 0.05 unless you cheat and say your study is special and should consider a different limit (they don't say this in their study).

That said, the only significant effect found of photo priming on high versus low fertility women was in the local attractive women group: high fertility women chose 65.8% sexy items versus low fertility's 39.1% (I could not find standard deviations for these values so have no idea how much the two groups overlap). These results are almost identical to those found when priming women with attractive women without saying if they are local or not.

How biological are we talking here?

The authors claim a biological cause for the differences found above. And maybe there is, to some extent. But there are two major issues with the authors’ conclusions.

First, there is the major methodological flaw of including women who probably aren't ovulating in their high-fertility group. Heads up to people who don't study female physiology: women, even healthy women with “normal” cycle lengths, don't ovulate every cycle. So if understanding a behavior during ovulation is important to your hypotheses, you need daily hormones on top of that LH test. Then, you know, if you can't document ovulation, you need to exclude those women from your sample. Oh, and while we're discussing methods, the authors don't mention whether the participants were in a relationship or not, or what their sexualities were, or their races or socioeconomic statuses. These are all important to understanding variation in female-female competition (Campbell 2004). And since ornamentation is likely related to honest signals of health, it would be good to know waist to hip ratios, or BMI, or facial symmetry (Streeter and McBurney 2003) (hello, I’m handing someone a dissertation here! Just remember to cite me correctly).

But the second issue relates to the theme I saw throughout this paper, that changes in mood or choice behavior due to ovulation or presence of attractive women is a "biological fact." Female-female competition is certainly found within human behavior, and behavior changes through the menstrual cycle. But is it fair to call these behaviors strictly biological, or should we have a more nuanced understanding of the interaction between biology and culture?

There are alternative cultural theories out there. Objectification theory proposes that there are consequences to living in a culture that sexually objectifies women: when women are continually appraised based on their looks, it leads to a disconnect between their body and individual (Moffitt and Szymanski 2011). This disempowers women and leads to them feeling as though their bodies exist for the pleasure of others. And if this is what women learn they have to offer others, and they seek affirmation, praise or attention from those around them, it makes sense for women to compete around attractiveness, particularly sexiness.

I would posit that shopping, particularly when primed with the image of an attractive woman, is a kind of objectification. So really, what Durante et al (2011) are measuring are the results of objectifying their study participants. Under these circumstances, a woman is more likely to start treating herself as an object to be evaluated on the basis of her appearance, so it makes sense that she would choose sexier clothing, in an effort to produce a culturally-appropriate, attractive body.

As the study stands, there is no way to parse out the impact of biology or culture -- and many cultures encourage objectification, female-female competition and female attractiveness towards men. As for how that interacts with high versus low fertility samples... that's the interesting part of this paper. If we can trust how the women are parsed. Which we can't, since some of the high-fertility sample might not have been ovulating.

These high heels are made of deer antlers

Antler booties from Camilla Skovgaard.
The authors also seemed enamored with the idea of comparing their female participants to male animals. Twice they mention the idea that they want to determine whether sexy clothing is analogous to a peacock's tail, a deer's antlers, or a lion's mane (really). These three examples, according to the authors, reflect a courtship function, a same-sex competition function, or both functions respectively. The authors go on to say that their results suggest that sexy dressing in women is like deer's antlers, or, a same-sex competition function.

First, since when are a deer's antlers only a same-sex competition function? Second, doesn't it say something that they couldn't find any examples of this kind of display in a female animal? This begs the question of why female humans do so much more displaying and maintenance of their appearance compared to other female animals, and again, this suggests interactions between biology and culture (Smuts 1995).

We can spin all the stories we want to explain why many human females make efforts to be physically attractive. And I do think Durante et al (2011) are on to something here as, despite methodological concerns they did find differences in high- and low-fertility choices. But if we continue to do this research on undergraduates in western contexts without sufficient hormone analysis, I'm unsure that its meaning extends beyond the participant pool.


Campbell, A. (2004). Female competition: Causes, constraints, content, and contexts Journal of Sex Research, 41 (1), 16-26 DOI: 10.1080/00224490409552210

Durante, KM, Griskevicius, V, Hill, SE, Perilloux, C, & Li, NP (2011). Ovulation, female competition, and product choice: hormonal influences on consumer behavior Journal of Consumer Research, 37 (6), 921-934

Fehring, R., Schneider, M., & Raviele, K. (2006). Variability in the Phases of the Menstrual Cycle Journal of Obstetric, Gynecologic, Neonatal Nursing, 35 (3), 376-384 DOI: 10.1111/j.1552-6909.2006.00051.x

Lenton EA, Landgren BM, Sexton L, & Harper R (1984). Normal variation in the length of the follicular phase of the menstrual cycle: effect of chronological age. British journal of obstetrics and gynaecology, 91 (7), 681-4 PMID: 6743609

Moffitt, L., & Szymanski, D. (2010). Experiencing Sexually Objectifying Environments: A Qualitative Study The Counseling Psychologist, 39 (1), 67-106 DOI: 10.1177/0011000010364551

Smuts, B. (1995). The evolutionary origins of patriarchy Human Nature, 6 (1), 1-32 DOI: 10.1007/BF02734133

Streeter, S. (2003). Waist–hip ratio and attractiveness New evidence and a critique of “a critical test” Evolution and Human Behavior, 24 (2), 88-98 DOI: 10.1016/S1090-5138(02)00121-6


  1. So I'm only an engineer but um...ancient Romans? Ancient greeks? Cross-culturally significant in the cultures they chose to examine (modern) only without a decent historical perspective?

  2. Female baboons demonstrate estrous via reddening of the buttocks. This would make a MUCH better comparison than deer antlers.

  3. I went and shared this with my husband, who has a BA in psychology. Thanks for posting!

  4. Thanks for interesting post again. Just a note, paired t-test is basically same as repeated measures anova. So this is not big deal.

  5. May I ask, who funds these types of studies?

  6. I'm not a doc either, but the emotional roller coaster ride stopped after eating Paleo for a few months.

  7. FrauTech, I agree. Male ornamentation is definitely higher in certain contexts!

    Anon #1, yes, estrus is certainly a way to demonstrate fertility to potential mates!

    Macha, I hope your husband enjoys the piece!

    Anon #2, this study was likely very inexpensive - really just a matter of building the fake shopping websites and small compensation for the subjects. Very likely the PhD student whose dissertation this is based on got some small university grant to fund it. But the article doesn't state where the funding came from.

    Anon #3, that's interesting to hear about paleo. There are certainly reasons to think that, for some people, that is a good thing to try, since diet composition can affect hormone levels and inflammation. I don't really experience a roller coaster, just a few days where my fuse is a little shorter than all the other days :).

  8. Sorry Mirchi, your comment was in moderation for some reason; I've released it. Ok, I feel better about the stats now!

  9. I wonder what the results of this study would be if it were performed on Muslim women who observe hijab...

  10. I've been told that Muslim women who observe hijab dress sexy underneath. The hijab would complicate the competition factor.

    This was an interesting and fun post. I enjoyed reading it.

    I wonder whether women who subconsciously don't want to get pregnant would dress less sexy during ovulation. Wow, this could produce a long list of dissertations.

  11. Modestgrrl, what a great point! There are culturally-specific behaviors and modes of dress that are ignored in this study, despite the "cross-culturally consistent" claim.

    Martha, maybe, but I would want to see some evidence before I embraced that particular claim. But for your other point... yes! Dissertations cropping up everywhere in this post :).

  12. Wow, what a great discussion thread! :)

    It'd be great to know the number of subjects of the study (studies?), we could estimate standard deviations from there.

    The ovulation confound should actually mitigate *against* your argument, though. Suppose some fraction F of woman were ovulating when they were marked as being in the ovulating group. Suppose also that there is a real behavioural difference between the actual ovulating and non-ovulating groups, whatever the cause. Suppose thirdly that everyone in the non-ovulating group is actually non-ovulating. The non-ovulating women in the ovulating group (1-F of them, by fraction) behave like non-ovulating women. Since there's a real difference between the groups, the measured effect size (difference between groups) is a factor of F smaller than the difference that you'd get between the groups if you had sorted them out correctly. Same argument applies in reverse for the opposite confound, namely that you got some ovulating women in the non-ovulating group. So if they found a statistically significant difference between the groups given their imperfect characterization of ovulation, the actual real difference between groups should be larger than the measured difference.

    OTOH, not controlling for sexual preference or relationship status is inexcusable. That's key information germane to topic of discourse.

    P.S. I want to see the results of your "ornamentation is likely related to honest signals of health, it would be good to know waist to hip ratios, or BMI, or facial symmetry" study!! Soon! :)

  13. Jamie Sukowicz (249)April 7, 2011 at 5:22 PM

    I found this to be a very interesting study, though there were definitely a few subjective measures. I like how you indicated that not every woman ovulates during her cycle and how there are so many personal factors that could have affected the participants. There's also the simple fact that some girls choose different clothing styles than others, and some may even feel more prone to certain clothes based on lifestyle adjustments (more likely to wear "sexy" clothes if they've been working out lately; more prone to looser clothes if they've gained weight). Their mindset at the time could have easily adjusted their choices as well. When I shop, I often hear my mother's voice in the back of my head telling me that something is too short/tight/revealing, and it prevents me from buying it. Other girls may not have that, and may even be thinking of what would look good to their boyfriend, etc (you did mention that the study could have looked at if the girls were in relationships).

  14. I can testify that I, and other women who observe hijab, do not wear "sexy clothing" underneath on a daily basis. That's not really the norm, and if a sister DID that, she certainly wouldn't go around telling everyone that, because she'd be deviating social norms.

    Regardless, I've seen what peeks out underneath abayas and jilbabs and it's usually a pair of jeans or even *gasp* flannel pajama pants. There's a tendency for women who wear outer covering to get, erm, lazy by Western standards regarding fashion. In fact, some Muslim women purposefully reject Western notions of sexiness and refuse to buy into the whole "Victoria's secret" concept of undergarments and whatnot.

  15. Wikisteff, I think you make a great point. I was thinking about that as I was writing the post, that it could mean the results are even stronger. But why oh why did they have to do the methods that way? Sigh.

    Jamie, I totally hear you. More evidence that we should be more interested in variation between women than just figuring out averages between two fertility states!

    modestgrrl, I'm so glad you shared that. And again, if we would actually study more than WEIRD women we might start to get a sense of the global, not so culturally consistent variation between women!

  16. Courtney Getz (249)April 7, 2011 at 11:00 PM

    I found the idea that females try to look sexier while ovulating very interesting, though there are certainly better ways to study this than the study by Durante et al. I think it would make sense for a women to try to look as attractive as possible during ovulation in order to attract a mate. One obvious problem, besides including possibly non-ovulating individuals in the analysis, is that the study seemed to take place in an entirely Western context. There are different ideas of what constitutes attractive and desirable across cultures, so what is "sexy" in a Western undergraduate population may not be in another. Also, women aren't the only ones that change their appearance in order to attract the opposite sex, men do it too. For instance, they were tank tops or tight shirts to show off their biceps, couldn't that be considered similar to a women wearing a tight pair of jeans or low-cut blouse to show off her assests. I would be interested in hearing more about studies done on this topic, especially studies that rectify some of the problems with the one conducted by Durante et al.

  17. I think culture is so important to humans that trying to separate out culture from biology is kind of missing the point of what it means to be human.

    so just make your study explicitly pertaining to American women... hand-waving about something being cross-cultural seems pointless.

  18. I agree with you. I think these results are interesting enough without stretching to make it universal. But if the study authors weren't trying to make their results universal for all humans, it wouldn't be evolutionary psychology. That is the rub the field keeps getting into.

  19. "The authors also seemed enamored with the idea of comparing their female participants to male animals. Twice they mention the idea that they want to determine whether sexy clothing is analogous to a peacock's tail, a deer's antlers, or a lion's mane (really)."

    Jesus Christ on toast, thank you for noticing this. THANK YOU FOR NOTICING THIS. This sort of garbage just smokes me. I have never once seen a single "study" done about "sex behaviors" that didn't at its heart stem from the desire of the clutch of paunchy, middle-aged males designing the study to justify why, were we living As We Were Meant To Live out on the savannah someplace, every 15 year old girl in the neighborhood would so be panting to get into his boxers.

  20. Thanks Red! And yes Janis, I hear you. I think a lot of evolutionary psychology is pseudo-intuitive... that is, it stems from bias, that is so ingrained that it feels like intuition. Once we start being as rigorous in our testing of ev psych hypotheses, and start testing them in different environments, we can better combat this underlying problem.