Why dual mating hypothesis research has failed to replicate

I began researching this article about a month ago to cover replication attempts of research supporting the dual mate hypothesis over the last ten years. In short, most recent research has failed to replicate effects supporting this hypothesis. Then on June 20, Steven W. Gangestad — one of the originators of the dual mate hypothesis himself — published a review of the literature in the journal Frontiers in Psychology covering this very topic (Gangestad & Dinh, 2022).

It is open access and you should read it: Women’s Estrus and Extended Sexuality: Reflections on Empirical Patterns and Fundamental Theoretical Issues.

My conclusions from reviewing the research turned out to be very similar to what Gangestad & Dinh wrote in their recent paper. When I was sent the notification for this paper I thought perhaps the originator of the hypothesis had a different take on the replication efforts. Unfortunately, in short, most recent research on the dual mate hypothesis has not been able to support it. 

And this has some major implications for pop psychology theories, especially in the manosphere and the realm of male dating advice, that relied heavily on this theory to explain female behavior.

A quick intro to the dual mate hypothesis

This hypothesis has a couple of names. The longest title I have read is the dual mate strategy hypothesis of ovulatory shifts. If you hear this referred to as the dual mating hypothesis/strategy or ovulatory shift hypothesis/strategy it is referring to the same thing.

The dual mate hypothesis suggests that women prefer “good genes,” or more physically masculine and attractive men, during the fertile phase of their ovulatory cycle. This may influence female behavior, such as a tendency to shift preference toward short term or uncommitted sexual relationships.

This can be conceptualized adjacent to an existing relationship, where female preference was initially for a longer term monogamous pair bond.

The idea is that women can secure a man who will form a long term relationship, provide resources and raise a child together — meanwhile she is able to secure the genes of a physically better man.

Infidelity is at least implied in this theory, if not absolutely necessary. The woman attempts to secure resources from one man while raising the offspring of another.

Alpha Fucks, Beta Bucks

Manosphere dating coaches and ideologies such as “The Red Pill” came up with a saying: “Alpha Fucks, Beta Bucks (AF/BB).” I don’t know if this was derived directly from the dual mate hypothesis, but I have seen the dual mate hypothesis frequently referenced to support AF/BB as “scientific.” Either way, it’s a similar construct.

The idea is that women secure a relationship with a less desirable provider “beta” male, while giving sexual access to a more physically desirable “alpha” male. If you have read my article on what the manosphere gets wrong about alphas and betas, you may immediately recognize some problems with this. For example, that providership is associated with higher, not lower, status.

AF/BB in manosphere ideology does not need to be constrained to relationships. It is also used to explain different priorities in mate preferences. A preference for providership versus a preference for physical attractiveness. This is aligned with the dual mate or ovulatory shift hypothesis. All of the following research will test to see if women have different mate preferences while fertile, both while single and while in a relationship.

The manosphere often lacks nuance, but hasn’t been completely without it. In real life we don’t see a clean decoupling between providership and physical attractiveness. The two usually covary in a given individual. Men high in status and dominance are more likely to be good providers. Thus, AF/BB as a construct seems to have low validity in slotting men into one group or the other.

To grapple with that fact — anyone can look around and see people aren’t neatly categorized into hot loser alphas and ugly rich betas — the manosphere also came up with the elusive “Alpha Bucks.” Basically, the alpha provider. And in reality the average married man or Good Monogamous Relationship Haver is probably close to the alpha provider archetype. Again, see my previous article for research supporting this.

It is up to you to decide how much the dual mate hypothesis overlaps with your version of AF/BB. As an internet meme AF/BB has a loose interpretation. However, be cautious of citing the dual mate hypothesis to support it. If this hypothesis has not panned out, which largely seems to be the case, then AF/BB is also inaccurate to the degree that it shares similarity with it.

Ovulation and mating behavior

At the core of the dual mate hypothesis is ovulation. Women go after “good genes” when they are fertile, per the hypothesis. Ovulation is also where we begin to meet replication issues, largely related to poor measurements of ovulation in early research.

Per Gangestad & Dinh (2022), the only thing that has really held up is that ovulation has an effect: women experience more sexual desire during ovulation. Unfortunately we don’t know the direction of that desire. It hasn’t been established that women prefer “good genes” or extra-pair partners more while fertile. It may simply be the case that women are more attracted to their own partners, more attracted to men in general, or hornier without any specific direction at all.

Here is the thing — I don’t want anyone to read this and think that ovulation has no effect. We may be unable to detect consistent relationships across recent replication efforts, but that does not mean some kind of relationship we haven’t tested for does not exist. It’s also possible that the effect is just very small. It’s very much an open question that is being researched at this moment.

But this also means you should be very skeptical of anyone claiming “it’s science bro” and citing the dual mate hypothesis as support for their folk wisdom about female behavior. The take home is that we just don’t know based on the best research we have. It’s not an established fact. Its current status is best described as something like: controversial hypothesis.

Wood et al. (2014)

A 2014 meta-analysis (Wood et al.) of 58 studies found that fertile women did not have a short-term mate preference for men with “good genes.” The main “alpha” measures here included high testosterone, dominance, and male sexual dimorphism. Conversely, women not in a fertile period of their ovulatory cycle did show a preference for both symmetrical men and healthier men, contrary to the ovulatory shift hypothesis.

A second issue uncovered in this meta was some marginal publication bias. Publication bias refers to the tendency for journals to publish statistically significant results, but not publish null results. This can create an illusion within a given discipline that a result is being consistently replicated when in reality it is not. Published research on the ovulatory shift was more likely to be statistically significant in this meta than unpublished research.

The date of publication and related effect sizes also indicated some degree of publication bias. The largest effect sizes all coincided with the earliest studies. The more recent the study, the more the effect size approached zero.

A third issue related to how ovulation was tracked. Large windows that estimated ovulation (more than six days) were more likely to report statistically significant results. Significant changes in female preferences for “good genes” were found only in studies that estimated a very wide window of ovulation. When ovulation was more exactly measured, the relationship disappeared. In short, some early significant findings may have been unrelated to the fertile phase of the cycle.

Poor early measurements of ovulation likely explain most of the recent failed replication attempts, which use more precise measurements with smaller windows. It seems that the more accurately we measure fertility the less it predicts a shift in mate preferences.

Gildersleeve et al. 2014

In 2014, a second meta-analysis of dual mate hypothesis research was conducted by (Gildersleeve et al., 2014). Unlike the meta by Wood et al., this meta did find significant effects across variables. Gangestad et al. responded in a paper and favored the second meta. Nonetheless Gangestad & Dinh (2022) would go on to say that most recent replication attempts have not been promising.

The point is not to pick a side and try to argue from the existing research who is correct. As more research and replication attempts are made this will be borne out. The point is to illustrate that this has been an ongoing debate within the literature for the past decade.

Replication attempts

Replication is a foundation of the scientific method. The idea is that you repeat the same study and see if the results come out the same. Alternately, you repeat a modified version of the study with a better design and see if the results still come out.

In the case of the ovulatory shift, recent studies with better methodology haven’t been able to replicate the results. The methodological issues tend to center around measurements of ovulation.

In early studies, ovulation was estimated with a wide window. Alternately, women were told to track ovulation and menstruation by diary. In more recent studies, windows of estimation have been narrowed. Ovulation can be tracked more or less exactly, by measuring luteinizing hormone (LH) in urine or saliva.

Mentioned previously, Gangestad & Dinh (2022) cited a number of replication attempts (Dixson et al., 2018; Jones et al., 2018c,d; Jünger et al., 2018a,b; Marcinkowska et al., 2018; Stern et al., 2019, 2020, 2021) that did not find a significant result in their recent review.

I have read at least one recent replication attempt that did not make this list. The point is not to make an exhaustive list. It is to give you some examples of recent replication efforts with good designs and why they have been failing.

Jünger et al. (2018)

Jünger et al. (2018) attempted to replicate ovulatory shift preferences and verified ovulation using a urine LH test. Long-term relationships were consistently rated as more desirable than short-term relationships, while desire for both increased during the fertile period:

How short and long term mating preferences change with the ovulatory cycle. From Jünger et al., 2018.

Partnered women rated all male bodies as more attractive during the fertile phase. However, none of the masculine traits measured (height, size, dimorphic body ratios and testosterone levels) interacted with the fertile phase. Women did not rate more masculine bodies as more attractive when fertile. Single women rated men the same across luteal and fertile phases.

Women did not rate more masculine bodies as more attractive when not fertile either. Only male physical strength, age and (low) BMI predicted higher levels of sexual attractiveness.

The authors concluded that they did not find a cycle-specific preference for short term, nor for masculine, men. Instead, women rated the same bodies as more or less attractive based on fertility. Imagine: if a woman rates you as a 5/10 during her luteal phase, now you are a 6/10 during her fertile phase. If you were a 7, now you are an 8. You get a little bump up when she is fertile, but ultimately your attractiveness stays relative to where it was.

This is consistent with a motivated priority shift (Roney & Simmons, 2017, as cited in Jünger et al., 2018). Women are simply more motivated to risk sex when they are fertile, but they don’t seek out new or qualitatively different partners.

Stein et al. (2019)

Stein et al. (2019) determined fertility using an LH test. Similar to Jünger et al., women reported greater sexual desire across multiple measures during their fertile phase. However, they did not detect any relationship between a desire for “Good Gene Traits” and the fertile period. The traits women preferred appeared similarly attractive across the cycle. Here are the only variables that correlated with the fertile phase:

Variables that did change with the ovulatory cycle. Partner preference did not. From Stein et al., 2019.

Interestingly, the only shift in partner perception was that their own actual partner appeared more “well-toned” to them during their fertile phase.

We see a similar outcome here as we did with Jünger et al.; partner preferences don’t change but sexual desire does. Women even view their actual partner in a physically more favorable way, at least with this single variable of body composition.

Jünger et al. (2018) (Second Study)

A second paper consisting of two studies by Jünger et al. (2018) looked at the potential relationship between masculine voices and ovulatory shift. Masculine voices are one of the most dimorphic human traits; there is more difference between a male and a female voice than many other physical features. Additionally, masculine voices closely reflect developmental (Butler et al., 1989; Harries et al., 1997, 1998; Hodges- Simeon et al., 2015, as cited in Jünger et al., 2018) and adult (Dabbs and Mallinger, 1999; Evans et al., 2008; Puts et al., 2012, 2016, as cited in Jünger et al., 2018) testosterone levels. Consequently, we should expect a preference for masculine voices as they are “true signals” of masculine “good genes.”

No relationship was found between cycle shifts and attractiveness ratings. Similar to Jünger et al.’s previous paper, women reported more attraction to all male voices in general during the fertile period of their cycle. Masculine voices were preferred over feminine voices, but to the same degree over all periods of the cycle.

Stern et al. (2020)

Stern et al. (2020) examined masculine behavior, specifically masculine competitive and courtship behavior, to determine if a relationship existed with female fertility.

LH tests were administered and precise hormone measurements were controlled for, down to the hour. Assessments of male bodies and voices were administered, as were indications of preference for short-term and long-term mate selection.

Actual dyadic (male-female) interactions were used. The interactions were rated for masculine short-term and long-term mate pursual behavior, as well as a list of masculine behavioral characteristics. The gaze of the men was analyzed with computer software to indicate which men sustained face-eye contact.

Just like the previous studies, women rated male sexual attractiveness higher during their fertile phases, although the effect was small. Women also rated male flirting attempts as more desirable during fertile phases. Women rated long-term relationship desirability the same across cycle phases.

All measures of masculine behavior predicted long-term relationship desirability across the cycle. Men who were more confident, dominant and assertive in their interactions were rated both more sexually attractive and more attractive as long-term partners, regardless of the cycle phase.

Women did not prefer more competitive men, nor men who showed more “alpha” courtship behaviors, during the fertile period of their cycle. From Stern et al., 2020.

Relationship status additionally did not have any interaction with the cycle phase.

Return to the legendary “Alpha Bucks”

Gangestad and Dinh (2021) recently reviewed data from Arslan et al. (2018) on how male physical attractiveness might interact with a potential ovulatory shift. The original paper by Arslan et al. found no effect, but a rerun of the data by Gangestad and Dinh found effects — fairly large sized effects for psychology.

Female partners of less attractive men were more sensitive to ovulatory shifts and indicated more preference for extra-pair partners. However, if the monogamous male partners of women were attractive the effect sizes approached zero. In essence, the ovulatory shift only appeared when the long-term male partner was less attractive.

The previous research I covered did not account for a partner attractiveness interaction. If you wanted to know about what’s going on with our legendary Alpha Bucks Male, the ideal male hybrid of provider and stud, this is likely your best current source. The methodology of this study (pre-registration, large sample, many behavioral variables accounted for) was also generally good.

There is an implication here for some manosphere ideology as well: specifically the claim that you should fear your monogamous partner leaving you for “Chad.” The most nihilistic depths of the manosphere — the so-called “blackpill” — might tell you that women are always on the sharp lookout for a marginally superior man. You’re a 6.8/10 and as soon as they find a 6.9/10 you are toast.

What we actually see here is that women are generally content with a partner who meets some threshold, even assuming the ovulatory shift is real. We can quantify that threshold as well:

Point estimate effects for physical attractiveness below or above one SD. From Gangestad & Dinh, 2021.

By the time that a man is one standard deviation above the mean — about 25% of men — the size of the effect of their partner showing interest in men outside of the relationship is close to zero. It is only when we see men who are below one standard deviation — the bottom 25% of men — that we really begin to see an effect size creep above medium-large.

Remember how I said that this was data rerun by Gangestad and Dinh from Arslan et al.’s paper? Arslan et al (2021) also responded and contested the robustness of the effects in this analysis.

Again, this is not so that you can pick a side in the debate. Rather, it is to show that these topics are being actively debated and researched. The point is that you should not view any of this as completely settled.

Extra-pair parenting and illegitimate children

The dual mate hypothesis asserts that women seek good genes by having affairs during their most fertile phase. They carry the child of the affair partner while using the long-term partner for resources.

To the extent that this could be true, we can estimate the frequency by looking at genetic research.

Larmuseau et al. (2016) conducted a recent review entitled Cuckolded Fathers Rare in Human Population and concluded, “The observed low EPP [extra-pair paternity] rates challenge the idea that women routinely ‘shop around’ for good genes by engaging in extra-pair copulations” and that “human EPP rates have stayed near constant at around 1% across several human societies over the past several hundred years.”

If you are interested in this topic you should start with this paper, as I believe it is the most current review of the literature on this topic.

Population-wide research of modern Europeans shows very low rates of extra-pair paternity, between 1-2% (Anderson, 2006 & Wolf et al., 2012, as cited in Larmuseau). Y-chromosome research indicating historical trends shows a similarly low rate between 1-2% for non-Western populations (Strassmann et al., 2012, as cited in Larmuseau) and for historical Western populations (Larmuseau, 2012; Greef & Erasmus, 2015; Boattini et al., 2015; Solé-Morata et al., 2015, as cited in Larmuseau 2016).

Assuming the dual mate strategy is real, very few men and women seem to be using it.

Summary points:

  1. Recent attempts have failed to replicate findings that support the dual mate hypothesis of ovulatory shift.
  2. Recent failures of replication are likely due to better methodology in measuring ovulation.
  3. Women experience more sexual desire and rate men as more attractive during the fertile phase of the cycle, but do not show a cycle-specific preference for more masculine traits, relationship styles or individuals.
  4. The same masculine traits are seen as more attractive across the cycle.
  5. Physical attractiveness may moderate cycle shift preferences; more attractive men probably have nothing to worry about.
  6. Extra-pair paternity rates do not support the dual-mate hypothesis; extra-pair paternity is very rare in modern society and rare in human genetic history.

References

Arslan, R. C., Driebe, J. C., Stern, J., Gerlach, T. M., & Penke, L. (2021). The evidence for good genes ovulatory shifts in Arslan et al.(2018) is mixed and uncertain.

Gangestad, S. W., & Dinh, T. (2022). Women’s Estrus and Extended Sexuality: Reflections on Empirical Patterns and Fundamental Theoretical Issues. Frontiers in Psychology, 3240.

Gangestad, S. W., & Dinh, T. (2021). Robust evidence for moderation of ovulatory shifts by partner attractiveness in Arslan et al.’s (2020) data.

Gildersleeve, K., Haselton, M. G., & Fales, M. R. (2014). Do women’s mate preferences change across the ovulatory cycle? A meta-analytic review. Psychological bulletin, 140(5), 1205.

Jünger, J., Kordsmeyer, T. L., Gerlach, T. M., & Penke, L. (2018). Fertile women evaluate male bodies as more attractive, regardless of masculinity. Evolution and Human Behavior, 39(4), 412-423.

Jünger, J., Motta-Mena, N. V., Cardenas, R., Bailey, D., Rosenfield, K. A., Schild, C., … & Puts, D. A. (2018). Do women’s preferences for masculine voices shift across the ovulatory cycle?. Hormones and Behavior, 106, 122-134.

Larmuseau, M. H., Matthijs, K., & Wenseleers, T. (2016). Cuckolded fathers rare in human populations. Trends in ecology & evolution, 31(5), 327-329.

Stern, J., Gerlach, T. M., & Penke, L. (2020). Probing ovulatory-cycle shifts in women’s preferences for men’s behaviors. Psychological Science, 31(4), 424-436.

Van Stein, K. R., Strauß, B., & Brenk-Franz, K. (2019). Ovulatory shifts in sexual desire but not mate preferences: An LH-test-confirmed, longitudinal study. Evolutionary Psychology, 17(2), 1474704919848116.

Wood, W., Kressel, L., Joshi, P. D., & Louie, B. (2014). Meta-analysis of menstrual cycle effects on women’s mate preferences. Emotion Review, 6(3), 229-249.

2 comments
  1. Even as a layman, in the last couple of years I had started to hear and read that this was at best, a hypothesis still being debated. When you first encounter it, it does sound very intuitive though.
    Thank you for this accessible and nuanced article.

    The best takeaway for me is that as a young guy, I should just try and improve myself by getting in the gym, become interesting through continued learning and develop skills that make me valuable in the world.

    1. Thanks for your comment! Yep as far as applicable dating advice for a young guy, hit the gym and try to build a good life for yourself. Probably good advice even for people uninterested in dating. The things that make us better, or make our lives better, also tend to make us more valuable mates.

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