Bateman's principle

Categories: Science, Theories

'''Bateman's principle''' holds that due to greater [[wikipedia:parental investment|parental investment]], [[Femoid|females]] tend to [[reproductive success|produce]] fewer offspring than [[Men|males]], but reproduce more reliably. Conversely, a few males have lots of offspring, but some males produce none. This means males have more variance in their [[reproductive success]].

There is debate as to whether this principle holds true across the animal kingdom as a whole, or only under certain conditions in some species, however the principle does hold for 94% of human societies that were considered in a 2009 study,<ref>Brown, G.R., Laland, K.N. and Mulder, M.B. 2009. ''Bateman's principles and human sex roles.'' [[https://www.sciencedirect.com/science/article/pii/S0169534709001128 FullText]]</ref> as well as for a variety of other species like birds and even certain kinds of fungi. Analyses of diversity of exclusively male and female parts of the DNA also show that women reproduced [[Scientific Blackpill#Before_.27enforced_monogamy.27.2C_women.27s_effective_population_size_was_up_to_17x_larger_than_men.27s|around twice as often]] as men which provides evidence men had more variance in reproductive success throughout human history. Moreover, a large study from 2016 did find a significant effect across many animal species, including humans.<ref>Janicke, T., et al. 2016. ''Darwinian sex roles confirmed across the animal kingdom.'' [[https://doi.org/10.1126/sciadv.1500983 Abstract]]</ref> In traditional societies, men’s reproduc­tive variances were estimated to be approximately 2–4 times those of women,<ref>Brown, Laland, & Borgerhoff Mulder, 2009</ref> and in the average forager society, 21% of married women are married polygynously.<ref>Marlowe & Berbesque, 2012</ref>

== Bateman's principle in humans ==

Women have greater parental investment, or more broadly a greater cost associated with reproduction, for a number of reasons:
* The production of eggs is more expensive than the production of sperm.
* Pregnancy is metabolically costly and long.
* Pregnancy and birthing is risky due to the large human head and high birth weight relative to the mother's body size.<ref>https://www.sciencefocus.com/nature/by-weight-which-animal-has-the-largest-baby-relative-to-body-size/</ref>
<!-- Women may also have a few years shorter fertile lifespan as giving birth requires youthful health.<ref>https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.20188</ref> This implies also older men compete for the few fertile young women, further aggravated by the fact that youngest women are the least likely not to have had already children, that the man would have had to provide for.-->
* The pocket shape of the female reproductive organ is more vulnerable to STDs.<ref>https://doi.org/10.1177/1754073917709940 (Al-Shawaf 2017)</ref>
* The offspring has higher dependence on the mother as only the mother is guaranteed to be present at birth and babies depend on women's breast milk.
* Human offspring is one of the most dependent offspring of all animals due to the complex socialization process and slow brain development that allows for higher intelligence and women were historically much more involved in raising the offspring than were men.<ref>https://incels.wiki/w/Scientific_Blackpill_(Supplemental)#Women_were_historically_predominantly_involved_in_cooking_and_they_never_dominated_men</ref>

For these reasons, females have lower expected lifetime [[reproductive success]] and a lower [[life history]] speed, so each of the few offspring is held to higher standards than men's. This makes women more [[libido|choosy, passive and coy]], meaning they defer sex. Men, on the other hand, can produce millions of sperm cells with little cost and can afford to carelessly impregnate many females ([[promiscuity]]), not needing to care for the offspring as much. Men have not much to lose [[pump and dump|pumping and dumping]] even low-quality women, barring STDs and embarrassment, but can gain opportunities for increasing their representation in the future gene pool, as well as increasing genetic variation of their offspring and increasing the chance that some offspring will survive and have high sexual success. This makes men [[sex drive|constantly horny]] with relatively much lower/promiscuous mate choice standards (except when they [[marriage|marry]], i.e. invest their resources, in which case they are also very choosy).

The greater number of sexually available men allows women to reproduce much more reliably, whereas few (alpha) males have a disproportionally high [[reproductive success|reproductive success]].
Since women are the limiting factor in reproduction (have a slower [[life history]]), men need to compete for [[dominance hierarchy|status]] in order to secure copulation opportunities.

There may be feedback effects that further reinforce Bateman's principle:

* Promiscuous low-quality men cause women to be even more coy, which further decreases their reproductive variance.
* Promiscuous men also give women more options to choose from, so they can also ''afford'' to be extra choosy in line with their [[female sneakiness|overall sneakiness]].
* As men are overall held more responsible and as they compete more (e.g. by bragging about sex), they also are also much more subjected to [[Matthew effect]]s, meaning the experience of downward or upward spirals which may further increase reproductive variance. 
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* As men need to compete more for reproductive opportunities, men evolve to be taller and stronger compared to women in an evolutionary arms race. As a result, women become extra choosy about men's strength as they need protection being relatively weak ([[bodyguard hypothesis]]).
* Men can brag about many sex partners as men are in part chosen based on their [[dominance hierarchy|status]] and sex evidences their status. (Though in some cultures they can also lose reputation, but not much.) Conversely, women cannot brag about this since women form [[pussy cartel]]s and ''shame'' free sex to avoid losing control over men.
* As ''homo faber'',<ref>https://en.wikipedia.org/wiki/Names_for_the_human_species#List_of_binomial_names</ref> the competitive accumulation of resources (goods, wealth, knowledge, social power) is important for survival in humans. Men specialized more on extracting resources, beeing less involved in reproduction and women specialized on extracting resources from men.
** This made women become choosy about men's resources (see [[hypergamy]]).
** Being more held more economically responsible and women being more dependent, men more likely are subject to [[Matthew effect]]s and hence more likely near the bottom end of society with poor historical survival rates, contributing to the sex difference in reproductive variance.
** The importance of resources made men (and their entire families) cautious about which women they invest their resources, which makes men very choosy about long-term partner choice. Further, families desire certainty about paternity to avoid investing other men's offspring ([[paternity assurance]]). This selects for easily controllable, cute and obedient women, reinforcing the sexual dimorphism and women's dependence (see [[neoteny]]). 
** Men's preference for obedient women motivates women to compete in denigrating other women's reputation of faithfulness, especially as women have less to gain from cooperating not being as involved in the business of resource extraction.<ref>https://www.sciencedirect.com/science/article/abs/pii/S0022103117304195</ref> Women's intrasexual competition is also harsher because women have not as much to gain from cooperation as men. Men face an trade-off between high and low investment, whereas women primarily want high investment from men, except when there is a prospect of copulating with a very attractive man (to get [[sexy sons]]). Not being able to brag about having sex contributes to inhibiting women's libido. Women face a trade-off between sexualizing themselves to attract higher-status males and avoiding gaining too much of a reputation for sluttiness.
** Family's [[female subordination|interest in controlling their women]] is in [[sexual conflict]] with women's desire to attract and get the genes of better men by sexualizing themselves (i.e. presenting their [[Fisherian runaway|sexually selected]] secondary sex characteristics), which only increases other's desire to control women.
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== Related phenomena ==

Differential parental investment can explain a wide variety of phenomena besides sex difference in reproductive variance:

* More parental investment means women have slower [[life history]] speed (LH), so their strategy is to only have high quality sex and late, and men's strategy is fast LH, meaning lots of sex and early. These sex differences have been found across 53 nations.<ref>https://www.ncbi.nlm.nih.gov/pubmed/17975724 (Lippa 2009)</ref>
* The resulting differences in activity level and competitiveness for reproductive opportunities implies that men have a high reproductive variance and women a low one, meaning men are more of a gamble, a high-risk/high-reward strategy. A result is that animals with pronounced differential parental investment evolve to produce more offspring in ecologically mild conditions to exploit potential high-reward of males, and to produce more female offspring in harsh conditions to ensure reproduction ([https://en.wikipedia.org/wiki/Trivers%E2%80%93Willard_hypothesis Trivers-Willard hypothesis]). Evidence of this in humans is for example billionaires having more male offspring.<ref>https://www.researchgate.net/publication/23785727_A_Trivers-Willard_Effect_in_Contemporary_Humans_Male-Biased_Sex_Ratios_among_Billionaires</ref>
* [[Hypergamy]], i.e. the tendency that women prefer men of better [[looks]], social or economic status, and higher education as a particular instance of choosiness and women's need to secure resources for their offspring.
* Why most historical achievements were done by men: Men, but not women, are biologically required to compete.
* Why humans are moderately polygynous across many cultures. 85% of all cultures have allowed polygyny to occur.<ref>https://en.wikipedia.org/wiki/Polygyny</ref>
* Why women are regarded as more valuable (women-are-wonderful effect) and men as more disposable.
* Why women wait longer before having sex, namely to await better options and test their partners.
* Why women switch mates, initiate divorces and become disinterested in sex sooner than men.
* Why women more likely regret sex and relationships.
* Why men have a higher cumulative demand for sex and hence why males experiencing inceldom outnumber females experiencing inceldom, e.g. social psychologist Roy Baumeister wrote about the ''Tragedy of the Male Sex Drive:''

{{Quote
|Given the mismatch between men's and women's desires, most men are doomed to experience chronic sexual frustration. […] [Men] are doomed to be horny.
|Roy Baumeister<ref>Baumeister, R.F. and Bushman, B., 2010. Social psychology and human nature, brief version. Nelson Education.</ref>
}}

== Increased sex imbalance ==

{{see_also|[[Hypergamy]]}}

Academics such as scholar [[Angela Nagle]] and sexologist [[Kristin Spitznogle]], and others such as [[Roger Devlin]] argue that imbalance in reproducive success has intensified recently, largely a result of [[Feminism|female sexual liberation]].{{Citation needed|reason=Ideally links to interviews or whatever}}

A study which analyzed GINI coefficients in number of sexual partners found that, "single men have a higher Gini coefficient (.536) than single women (.470). Thus, female sexual partners are more unequally distributed among single men than male sexual partners are among single women."<ref>https://contexts.org/blog/who-has-how-many-sexual-partners/</ref>

A study that analyzed changes in the distribution of sex partners from 2002 to 2011-2013 showed that compared to 2002, top 20% of men (in terms of [[LMS]]) now had a 25% increase in sexual partners, and the top 5% of men had an outstanding 38% increase in the number of sexual partners. The study commented that “no significant changes were identified among women in the top 20% and top 5%, overall, and among subgroups”.<ref>https://journals.lww.com/stdjournal/Fulltext/2017/02000/Changes_in_the_Distribution_of_Sex_Partners_in_the.5.aspx</ref>

While the rate of the sexless in the U.S. has increased for both men and women in the recent decades, it has increased more for men than for women.<ref>https://incels.wiki/w/Demographics_of_inceldom</ref>

The largest increase of sex imbalance has been observed in [[Demographics#Finland|Finland]], which is a very sexually liberal country and may be similar to liberal subcultures in other countries.

==References==
<references />

==See also==
*[[Scientific Blackpill]]
* [[Evolution]]
*[[Sexual dimorphism]]
*[[Fisherian runaway]]
*[[Hypergamy]]
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