Sexual selection in humans

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Mutation and Selection

Sexual selection in humans concerns the concept of sexual selection, introduced by Charles Darwin as an element of his theory of natural selection,[1] as it affects humans. Sexual selection is a biological way one sex chooses a mate for the best reproductive success. Most compete with others of the same sex for the best mate to contribute their genome for future generations. This has shaped human evolution for many years, but reasons why humans choose their mates are not fully understood. Sexual selection is quite different in non-human animals than humans as they feel more of the evolutionary pressures to reproduce and can easily reject a mate.[2] The role of sexual selection in human evolution has not been firmly established although neoteny has been cited as being caused by human sexual selection.[3] It has been suggested that sexual selection played a part in the evolution of the anatomically modern human brain, i.e. the structures responsible for social intelligence underwent positive selection as a sexual ornamentation to be used in courtship rather than for survival itself,[4] and that it has developed in ways outlined by Ronald Fisher in the Fisherian runaway model.[5][6][7][8][9] Fisher also stated that the development of sexual selection was "more favourable" in humans.[10]

General hypotheses[edit]

Some hypotheses about the evolution of the human brain argue that it is a sexually selected trait, as it would not confer enough fitness in itself relative to its high maintenance costs (a fifth to a quarter of the energy and oxygen consumed by a human).[11] Current consensus about the evolutionary development of the human brain accepts sexual selection as a potential contributing factor but maintains that human intelligence and the ability to store and share cultural knowledge would have likely carried high survival value as well.[12]

Sexual selection's role in human evolution cannot be definitively established, as features may result from an equilibrium among competing selective pressures, some involving sexual selection, others natural selection, and others pleiotropy. Richard Dawkins argued that

"When you notice a characteristic of an animal and ask what its Darwinian survival value is, you may be asking the wrong question. It could be that the characteristic you have picked out is not the one that matters. It may have "come along for the ride", dragged along in evolution by some other characteristic to which it is pleiotropically linked."[13]

Darwin's sexual selection hypothesis[edit]

Charles Darwin described sexual selection as depending on "the advantage which certain individuals have over others of the same sex and species, solely in respect of reproduction".[14] Darwin noted that sexual selection is of two kinds and concluded that both kinds had operated on humans:[15] "The sexual struggle is of two kinds; in the one it is between the individuals of the same sex, generally the male sex, in order to drive away or kill their rivals, the females remaining passive; whilst in the other, the struggle is likewise between the individuals of the same sex, in order to excite or charm those of the opposite sex, generally the females, which no longer remain passive, but select the more agreeable partners."[16]

Charles Darwin conjectured that the male beard, as well as the hairlessness of humans compared to nearly all other mammals, were results of sexual selection. He reasoned that since the bodies of females are more nearly hairless, the loss of fur was due to sexual selection of females at a remote prehistoric time when males had overwhelming selective power, and that it nonetheless affected males due to genetic correlation between the sexes. He also hypothesized that contrasts in sexual selection acting along with natural selection were significant factors in the geographical differentiation in human appearance of some isolated groups, as he did not believe that natural selection alone provided a satisfactory answer. Although not explicit, his observation that in Khoisan women "the posterior part of the body projects in a most wonderful manner" (known as steatopygia)[17] implies sexual selection for this characteristic. In The Descent of Man, and Selection in Relation to Sex, Darwin viewed many physical traits which vary around the world as being so trivial to survival[18] that he concluded some input from sexual selection was required to account for their presence. He noted that variation in these features among the various peoples of the world meant human mate-choice criteria would also have to be quite different if the focus was similar, and he himself doubted that, citing[19] reports indicating that ideals of beauty did not, in fact, vary in this way around the world.

Sexual dimorphism[edit]

The effects on the human brain formation during puberty is directly linked to hormones changes. The mismatch timing between biological puberty and age of social maturity in western society has a psychological expectation on children.[20] With puberty, men are generally hairier than women, and Darwin was of the opinion that hairlessness was related to sexual selection; however, several other explanations have been advanced to explain human hairlessness; a leading one being that loss of body hair facilitated sweating.[21] This idea closely relates to that of the suggested need for increased photoprotection and is part of the most-commonly-accepted scientific explanation for the evolution of pigmentary traits.[22]

Sexual dimorphism suggests the presence of sexual selection. The earliest homininae were highly dimorphic and that this tendency lessened over the course of human evolution, suggesting humans have become more monogamous. In contrast, gorillas living in harems exhibit a much stronger sexual dimorphism (see: homininae).[23]

Sexual anatomy[edit]

The theory of sexual selection has been used to explain a number of human anatomical features. These include rounded breasts, facial hair, pubic hair and penis size. The breasts of primates are flat, yet are able to produce sufficient milk for feeding their young. The breasts of non-lactating human females are filled with fatty tissue and not milk. Thus it has been suggested the rounded female breasts are signals of fertility.[24] Richard Dawkins has speculated that the loss of the penis bone in humans, when it is present in other primates, may be due to sexual selection by females looking for a clear sign of good health in prospective mates. Since a human erection relies on a hydraulic pumping system, erection failure is a sensitive early warning of certain kinds of physical and mental ill health.[25]

Homo has a thicker penis than the other great apes, though it is on average no longer than the chimpanzee's.[26] It has been suggested the evolution of the human penis towards larger size was the result of female choice rather than sperm competition, which generally favors large testicles.[27] However, penis size may have been subject to natural selection, rather than sexual selection, due to a larger penis' efficiency in displacing the sperm of rival males during sexual intercourse. A model study showed displacement of semen was directly proportional to the depth of pelvic thrusting, as an efficient semen displacement device.[28]

Selection preferences and biological drivers[edit]

There are a variety of factors that drive sexual selection in humans. Current available research indicates that selection preferences are biologically driven,[29] that is, by the display of phenotypic traits that can be both consciously and unconsciously evaluated by the opposite sex to determine the health and fertility of a potential mate.[30] This process can be affected, however, by social factors, including in cultures where arranged marriage is practiced, or psychosocial factors, such as valuing certain cultural traits of a mate, including a person's social status, or what is perceived to be an ideal partner in various cultures.[31]

Selection preferences in females[edit]

Some of the factors that affect how females select their potential mates for reproduction include voice pitch, facial shape, muscular appearance, and height.[32][33] Several studies suggest that there is a link between hormone levels and partner selection among humans. In a study measuring female attraction to males with varying levels of masculinity, it was established that women had a general masculinity preference for men's voices, and that the preference for masculinity was greater in the fertile phase of the menstrual cycle than in the non-fertile phase.[33] There is further evidence from the same study that in fertile stages of the menstrual cycle, women also had a preference for other masculine traits such as body size, facial shape, and dominant behavior, which are indicators of both fertility and health.[33] This study did not exclude males with feminine traits from being selected, however, as feminine traits in men indicate a higher probability of long-term relationship commitment,[33] and may be one of several evolutionary strategies.[34] Further research also backs up the idea of using phenotypic traits as a means of assessing a potential mate's fitness for reproduction as well as assessing whether a partner has high genetic quality.[35]

One study proposed a link between Human Development Index levels and female preference for male facial appearance.[36] While women from the United Kingdom preferred the faces of men with low cortisol levels, women from Latvia did not discriminate between men with either high or low levels of cortisol.[36] It was concluded that societal-level ecological factors impact the valuation of traits by combinations of sex- and stress-hormones.[36]

A 2020 study reported that women tend to find a man more attractive if the man's previous relationships ended mutually, and less attractive if the man was dumped.[37]

Selection preferences in males[edit]

Like their female counterparts, males also use visual information about a potential mate, as well as voice, body shape, and an assortment of other factors in selecting a partner. Research shows that males tend to prefer feminine women's faces and voices as opposed to women with masculine features in these categories.[38] Furthermore, males also evaluate skin coloration, symmetry, and apparent health, as a means by which they select a partner for reproductive purposes.[38] Males are particularly attracted to femininity in women's faces when their testosterone levels are at their highest, and the level of attraction to femininity may fluctuate as hormone levels fluctuate.[39] Studies on men have also been done to show the effects of exogenous testosterone and its effects on attraction to femininity, and the results concluded that throughout several studies, men have shown decreased preference for feminine female faces in the long-term context, when given exogenous testosterone, but this difference did not occur with placebo.[40]

Common preferences in either sex[edit]

Sexual selection preferences are general terms by which the mating and reproductive process are understood. As one article states, sexual selection is in essence a process which favors sexual displays for attraction, aggressiveness, dominance, size, and strength, and the ability to exclude competitors by force if necessary, or by using resources to win.[41] Both male and female use voice, face, and other physical characteristics[31] to assess a potential mate's ability to reproduce, as well as their health.[30] Together with visual and chemical signals, these crucial characteristics which are likely to enhance the ability to produce offspring, as well as long-term survival prospects, can be assessed and selections made.[29][42]

Sexual selection in males[edit]

Contest competition[edit]

Contest competition is form of sexual selection in which mating is obtained by using force or the threat of force to exclude same-sex competitors from mates.[43] Male contest competition favors large body size, which is seen in the sexual dimorphism of human males and females.[44] In all living hominid species, males are more muscular, allowing them to have more strength and power. Human males have 61% more overall muscle mass compared to females.[45] This greater muscle mass allows males to gain greater acceleration, speed, and more powerful striking movements.[46] Compared to females, human males exhibit more same-sex aggression, which peaks in young adulthood.[47][48][49][50]

Male contest competition also often favors threat displays, which allow one competitor to submit without a costly fight.[51] Low vocalization fundamental frequencies (perceived as vocal pitch) increase the perception of threat among human males.[52][53][54] Controlling for body size, lower male fundamental frequency relative to females tends to evolve in polygynous anthropoid primates, where males compete more intensely for mates.[55] Chimpanzees and humans have the greatest sexual dimorphism in fundamental frequency of all hominids.[55] Males are also more likely to engage in physical risks in front of competitors, and males who take more physical risks are perceived as being stronger.[56] Status badges such as facial hair are generally related to men being perceived as more dominant.[43] Facial hair makes the jaw appear more prominent and shows emotions like anger clearly which makes a male appear more threatening.[57][58] Dominance has been associated with increased male mating success.[59][60][61]

Often contest competition produces anatomical weapons such as antlers or large canine teeth; however, hominids lack canine weaponry typical of other primates.[43] Reduced canine size may be due to bipedalism and adaptations of the hand.[62][63] Bipedalism is not a common trait, yet many species like the great apes stand on their hind legs when fighting, which increases power behind blows.[64][43] Hominin hands are adapted for gripping tools or hurling objects like stones.[65][66][67][68] Bipedalism and utilizing handheld objects such as weapons may have aided early hominins in contest competition, reducing sexual selection pressures of maintaining large canine teeth.[62][67][69]

Several other traits in human males may have been selected for contest competition. Males exhibit a more robust face compared to females.[43] This may have provided protection against blows to the face during contest competitions as the areas on the skull that have increased robusticity are parts that are more likely to suffer from injury.[70] Additionally, there are 23% more lefthanded males than females.[71] Although left-handedness is heritable and associated with survival disadvantages, the rarity of left-handedness may have given ancestral males a fighting advantage in competitions keeping this trait in the gene pool via negative frequency-dependent selection.[43][72][73][74] Many combat sports such as boxing have higher-than-chance frequencies of left-handed individuals among the top competitors.[75] Human males are also able to tolerate pain longer than females, especially during competition.[43][76][77] A higher pain tolerance allows for males to remain aggressive during contests along with an increased aerobic capacity.[43] Males have an oxygen capacity rate that is 25–30% higher than females.[78][79] This aerobic capacity increases during puberty when males are sexually maturing and preparing to mate.[43]

Human males engage in both within-group contest competition and coalitional aggression.[43] The latter form competition may be supported by males tending to contribute more to a group task when competing against other groups and to discriminate more strongly against outgroup members.[80][81][82][83]

Traits that evolve during contest competition, such as large body size and physical aggression, are often costly to produce and maintain.[84] These traits may therefore be indicators of male genetic quality and/or ability to provide resources and other direct benefits.[84] Consequently, human females may evolve preferences for these traits, which then comprise an additional selection pressure.  However, secondary sexual characteristics in human males do not always enhance overall attractiveness to females.[85][86][87] Some traits of human males that function in contests, such as body size, strength, and weaponry usage, may also have been selected to aid in hunting.[43] However, contest competition is observed in all great apes and thus likely preceded hunting as a selective pressure.[43]

Sexual selection in females[edit]

Human female mating competition is complex and multifaceted and varies across cultures, societies, and individuals.[88] Females may compete for high-quality mates who possess traits that indicate underlying genetic quality, possibly including physical attractiveness and intelligence,[89] or material resources that can enhance the survival and reproductive success of the female and her offspring.[90][89]

Females may also compete for leadership and reputation in social alliances and networks that can provide support, protection, and mating opportunities.[91][92] Human females compete with other females, sometimes including co-wives, to obtain and retain investment from mates, while managing cooperative same-sex relationships.[93]

Female mate competition[edit]

Over human evolution, the cost of aggressive and physical contests in females may have been high given that females were the primary caregivers and protectors of offspring, so a mother's death greatly impacts infant mortality.[91][92] Some behaviors from mothers competing with other females at a similar life stage over resources include self-promotion and competitor derogation.[92] However, maternal competition remains understudied. Compared to male aggression, female aggression tends to be more indirect. Females tend to engage in more subtle and indirect aggression, such as gossip, as a competitive tool to harm same-sex rivals' social opportunities[94] and partake in competitor derogation to prevent female rivals from getting male attention.[92] Gossip, derogation, and social exclusion grant the aggressor the chance to go undetected and avoid retaliation. Derogation, for example, can eliminate same-sex rivals by reducing their ability to compete; it was found that girls' suicide attempts were associated with any amount of indirect peer victimization, whereas only frequent indirect peer victimization was associated with boys' suicide attempts.[92] Furthermore, same-sex harassment in some nonhuman animals impacted females' ovulation capabilities, which suggests that human females' reproductive success could be influenced by the stress induced by indirect or direct peer victimization.[92] Males pursue both sexually attractive and faithful long-term partners, which might be the source of female mating competition greatly revolving around denigrating same-sex rivals' attractiveness and reputation through accusations of promiscuity and infidelity.[92] Competitive women are more likely to spread reputation-harming information about other women, suggesting that reputation manipulation is a form of female competition for romantic partners.[95] Women are more likely to compete for desirable mates when maternal investment levels are high, and their social groups are largely composed of mothers,[96] as more women living closer together are looking for similar resources that benefit their own survival and that of their children.[92]

Sexually selected female traits[edit]

Competition for mates among human females may take multiple forms. Contests tend to be less frequent, aggressive, and injurious than male-male contests.[97] This leads to a difference in the traits selected. The indirect aggression in which females engage can take the form of damaging the reputation of other women (e.g., via gossip), potentially influencing their sexual behavior and opportunities.[98] Additionally, females compete with one another through male mate choice, e.g., by enhancing their own physical attractiveness.[98] Some female anatomical traits are targets of male mate choice and possibly represent female sexual ornaments shaped by selection. Femininity in the female face and voice provide cues to female reproductive hormones and reproductive potential.[99] Males tend to have lower pitched voices than females, likely due to male intrasexual competition,[100] but some evidence suggests that high female voice pitch may also be favored by male mate choice and function in intrasexual competition among females.[87]

Deposition of fat on the hips, buttocks, and breasts in human females may also be an outcome of female sexual selection, signaling the ability to support gestation and lactation for offspring in environments where resources may be low.[101][102] However, in the Western World, women with larger breasts are seen as more likely to commit infidelity and more likely to participate in intra-sexual competition with other females.[101] Greater overall body fat percentage in human females appears to be unique among primates and may function in storing resources needed to gestate and support large-brained offspring[103] as well as in sexual selection.[104] For example, higher female body mass index (BMI) is associated with increased fertility in young women, particularly those in subsistence societies.[105] Lower WHR, lower BMI, and smaller waist sizes are also associated with lower birth weights and higher infant mortality.[106] Such traits, particularly body fat distribution, may represent sexual ornamentation, which is important in mating throughout the animal kingdom, for example, in birds.[107][108] Humans also use bodily decoration, including jewelry, tattoos, scarification, and makeup to enhance appearance and desirability to potential mates.[101][109]

It has also been suggested that women who are nearing ovulation were more likely to be judged as more attractive than their counterparts who were in different stages of their cycle.[110] Facial and vocal attractiveness have been observed to change with estradiol and progesterone in pattens consistent with fertility-related increases,[111] although some data challenge this interpretation.[112] In general, ovulatory cycle changes are more subtle than in non-human primates, perhaps representing leakage of information on fertility and hormonal status rather than signals functioning to convey this information.[113]  

Phenotype[edit]

John Manning[114] suggests that where polygyny is common, there is also a higher disease burden, resulting in selection for antimicrobial resistance. In this view, the antimicrobial properties of melanin help mitigate the susceptibility to disease in sub-Saharan Africa. According to this argument, the anti-infective qualities of melanin were more important than protection from ultraviolet light in the evolution of the darkest skin types. Manning asserts that skin color is more correlated with the occurrence of polygyny – because melanin has an antimicrobial function – than the latitudinal gradient in intensity of ultraviolet radiation.[114][115]

Research seems to contradict Manning's explanation about skin color. The analysis of indigenous populations from more than 50 countries has shown that the strongest correlation with light skin is upper latitude.[116] Rogers et al. (2004) concluded that dark skin evolved as a result of the loss of body hair among the earliest primate ancestors of humans.[117][118][119] and protect from folate depletion due to the increased exposure to sunlight.[120] When humans started to migrate away from the tropics, where there is less-intense sunlight, lighter skin is able to generate more vitamin D than darker skin, so it would have represented a health benefit in reduced sunlight, leading to natural selection for lighter skin.[118][121]

Anthropologist Peter Frost has proposed that sexual selection for women with unusual hair, skin or eye color was responsible for the evolution of pigmentary traits in European populations,[122] however this theory has since been refuted by data-based evidence from genetics and spectophotometry,[123][124] and multiple studies have shown that women with the pigmentary characteristics of East Asian women are considered more attractive than European women.[125][126][127]

Geoffrey Miller hypothesis[edit]

Homo habilis – forensic facial reconstruction

Geoffrey Miller, drawing on some of Darwin's largely neglected ideas about human behavior, has hypothesized that many human behaviors not clearly tied to survival benefits, such as humor, music, visual art, some forms of altruism, verbal creativity, or the fact that most humans have a far greater vocabulary than that which is required for survival, can nevertheless play a role.[128] Miller (2000) has proposed that this apparent redundancy is due to individuals using vocabulary to demonstrate their intelligence, and consequently their "fitness", to potential mates. This has been tested experimentally, and it appears that males do make greater use of lower-frequency (more unusual) words when in a romantic mindset compared to a non-romantic mindset, suggesting that vocabulary is likely to be used as a sexual display (Rosenberg & Tunney, 2008). All these qualities are considered courtship adaptations that have been favored through sexual selection.[129]

Miller is critical of theories that imply that human culture arose as accidents or by-products of human evolution. He believes that human culture arose through sexual selection for creative traits. In that view, many human artifacts could be considered subject to sexual selection as part of the extended phenotype, for instance clothing that enhances sexually selected traits.[2] During human evolution, on at least two occasions, hominid brain size increased rapidly over a short period of time followed by a period of stasis. The first period of brain expansion occurred 2.5 million years ago, when Homo habilis first began using stone tools. The second period occurred 500,000 years ago, with the emergence of archaic Homo sapiens. Miller argues that the rapid increases in brain size would have occurred by a positive feedback loop resulting in a Fisherian runaway selection for larger brains. Tor Nørretranders, in The Generous Man conjectures how intelligence, musicality, artistic and social skills, and language might have evolved as an example of the handicap principle, analogously with the peacock's tail, the standard example of that principle.

Opposing arguments[edit]

The role of sexual selection in human evolution has been considered controversial from the moment of publication of Darwin's book on sexual selection (1871). Among his vocal critics were some of Darwin's supporters, such as Alfred Wallace, a believer in spiritualism and a non-material origin of the human mind, who argued that animals and birds do not choose mates based on sexual selection, and that the artistic faculties in humans belong to their spiritual nature and therefore cannot be connected to natural selection, which only affects the animal nature.[10] Darwin was accused of looking to the evolution of early human ancestors through the moral codes of the 19th century Victorian society.

See also[edit]

References[edit]

  1. ^ Vogt, Yngve (29 January 2014). "Large testicles are linked to infidelity". Phys.org. Retrieved 31 January 2014.
  2. ^ a b Miller G. (2000). The mating mind: how sexual choice shaped the evolution of human nature, London, Heineman, ISBN 0434007412 (also Doubleday, ISBN 0385495161).
  3. ^ Brin, David. "Neoteny and Two-Way Sexual Selection in Human Evolution". www.davidbrin.com.
  4. ^ "Sexual Selection and the Mind". www.edge.org.
  5. ^ Fisher, R.A. (1930) The Genetical Theory of Natural Selection. ISBN 0198504403
  6. ^ Edwards, A.W.F. (2000) Perspectives: Anecdotal, Historical and Critical Commentaries on Genetics. The Genetics Society of America (154) 1419:1426
  7. ^ Andersson, M. (1994) Sexual selection. ISBN 0691000573
  8. ^ Andersson, M. and Simmons, L.W. (2006) Sexual selection and mate choice. Trends, Ecology and Evolution (21) 296:302
  9. ^ Gayon, J. (2010) Sexual selection: Another Darwinian process. Comptes Rendus Biologies (333) 134:144
  10. ^ a b Fisher, R. A. (1915). "The evolution of sexual preference". Eugenics Review. 7 (3): 184–192. PMC 2987134. PMID 21259607.
  11. ^ Schillaci, M. A. (2006). "Sexual selection and the evolution of brain size in primates". PLOS ONE. 1 (1): e62. Bibcode:2006PLoSO...1...62S. doi:10.1371/journal.pone.0000062. PMC 1762360. PMID 17183693. Open access icon
  12. ^ McElreath, Richard (May 2018). "Sizing up human brain evolution". Nature. 557 (7706): 496–497. Bibcode:2018Natur.557..496M. doi:10.1038/d41586-018-05197-8. PMID 29789743.
  13. ^ Richard Dawkins (2009). The Greatest Show on Earth: The Evidence for Evolution. Simon and Schuster. p. 67. ISBN 978-1416597780.
  14. ^ Darwin, Charles (1871). The Descent of Man and Selection in Relation to Sex. Vol. 1 (1st ed.). London: John Murray. p. 256.
  15. ^ Darwin, Charles (1871). The Descent of Man and Selection in Relation to Sex. Vol. 2 (1st ed.). London: John Murray. p. 402.
  16. ^ Darwin, Charles (1871). The Descent of Man and Selection in Relation to Sex. Vol. 1 (1st ed.). London: John Murray. p. 398.
  17. ^ Charles Darwin (1882). The Descent of Man and Selection in Relation to Sex. London: John Murray. p. 578.
  18. ^ Charles Darwin (1882). The Descent of Man, and Selection in Relation to Sex. AMS Press. pp. 605. ISBN 978-0404084097. The races of man differ from each other, and from their nearest allies, in certain characters which are of no service to them in their daily habits of life, and which it is extremely probable would have been modified through sexual selection
  19. ^ Darwin, C. (1936) [1888]. The Descent of Man and Selection in Relation to Sex. reprint of 2nd ed., The Modern Library, New York: Random House.
  20. ^ Gluckman, P. D.; Hanson, M. A. (25 July 2006). "Changing times: The evolution of puberty". Molecular and Cellular Endocrinology. 254–255: 26–31. doi:10.1016/j.mce.2006.04.005. PMID 16713071. S2CID 8724902.
  21. ^ Jablonski, N. G. (2006). Skin: a natural history. Berkeley, CA: University of California Press. p. PP13.
  22. ^ Jablonski, N. G.; Chaplin, G. (2010). "Human skin pigmentation as an adaptation to UV radiation". Proceedings of the National Academy of Sciences. 107 (Suppl 2): 8962–8968. Bibcode:2010PNAS..107.8962J. doi:10.1073/pnas.0914628107. PMC 3024016. PMID 20445093.
  23. ^ Principles of Human Evolution, by Roger Lewin, Robert Foley.[page needed]
  24. ^ Morris, Desmond (2007). "Breasts". The Naked Woman. Macmillan. ISBN 978-0312338534.
  25. ^ Dawkins, Richard (2006) [1976]. The Selfish Gene (30th anniversary ed.). p. 158 endnote. It is not implausible that, with natural selection refining their diagnostic skills, females could glean all sorts of clues about a male's health, and the robustness of his ability to cope with stress, from the tone and bearing of his penis.
  26. ^ Dixson, A. F. (2009). Sexual selection and the origins of human mating systems. Oxford University Press. pp. 61–65. ISBN 978-0191569739.
  27. ^ Miller, G.F. (1998), "How mate choice shaped human nature: A review of sexual selection and human evolution" in Handbook of Evolutionary Psychology.
  28. ^ In a theoretical paper[usurped] published in the journal Evolutionary Psychology in 2004, Gallup and coauthor, Rebecca Burch, conjecture that, "A longer penis would not only have been an advantage for leaving semen in a less-accessible part of the vagina, but by filling and expanding the vagina, it also would aid and abet the displacement of semen left by other males as a means of maximizing the likelihood of paternity." – "Secrets of the Phallus: Why Is the Penis Shaped Like That?", ScientificAmerican.com.
  29. ^ a b Grammer, Karl; Fink, Bernhard; Møller, Anders P.; Thornhill, Randy (1 August 2003). "Darwinian aesthetics: sexual selection and the biology of beauty". Biological Reviews. 78 (3): 385–407. doi:10.1017/s1464793102006085. ISSN 1469-185X. PMID 14558590. S2CID 25257668.
  30. ^ a b Rhodes, Gillian; Chan, Janelle; Zebrowitz, Leslie A.; Simmons, Leigh W. (7 August 2003). "Does sexual dimorphism in human faces signal health?". Proceedings of the Royal Society of London B: Biological Sciences. 270 (Suppl 1): S93–S95. doi:10.1098/rsbl.2003.0023. ISSN 0962-8452. PMC 1698019. PMID 12952647.
  31. ^ a b Price, Michael E.; Pound, Nicholas; Dunn, James; Hopkins, Sian; Kang, Jinsheng (2 January 2013). "Body Shape Preferences: Associations with Rater Body Shape and Sociosexuality". PLOS ONE. 8 (1): e52532. Bibcode:2013PLoSO...852532P. doi:10.1371/journal.pone.0052532. PMC 3534680. PMID 23300976.
  32. ^ Buss, David (2019). "Women's Long-Term Mating Strategies". Evolutionary Psychology: The New Science of the Mind (6th ed.). Routledge. ISBN 978-0429590061.
  33. ^ a b c d Feinberg, D. R.; Jones, B. C.; Law Smith, M. J.; Moore, F. R.; DeBruine, L. M.; Cornwell, R. E.; Hillier, S. G.; Perrett, D. I. (1 February 2006). "Menstrual cycle, trait estrogen level, and masculinity preferences in the human voice". Hormones and Behavior. 49 (2): 215–222. doi:10.1016/j.yhbeh.2005.07.004. PMID 16055126. S2CID 14884832.
  34. ^ "Strategies for Animal Survival 2 (Animal Studies Series)". Chip Taylor Communications.
  35. ^ Shaw, Fionna (2009). Influence of female 2D:4D ratio on attractiveness of male vocal and facial masculinity (Dissertation). hdl:1842/3604.
  36. ^ a b c Moore, F. R.; Coetzee, V.; Contreras-Garduño, J.; Debruine, L. M.; Kleisner, K.; Krams, I.; Marcinkowska, U.; Nord, A.; Perrett, D. I. (23 June 2013). "Cross-cultural variation in women's preferences for cues to sex- and stress-hormones in the male face". Biology Letters. 9 (3): 20130050. doi:10.1098/rsbl.2013.0050. ISSN 1744-9561. PMC 3645036. PMID 23536442.
  37. ^ Scammell, Emily; Anderson, Ryan C. (2020). "Female Mate Copying: Measuring the Effect of Mate-Relevant Information Provided by Former Partners". Evolutionary Psychological Science. 6 (4): 319–327. doi:10.1007/s40806-020-00239-9. S2CID 218948364.
  38. ^ a b O'Connor, Jillian J. M.; Fraccaro, Paul J.; Pisanski, Katarzyna; Tigue, Cara C.; Feinberg, David R. (31 July 2013). "Men's Preferences for Women's Femininity in Dynamic Cross-Modal Stimuli". PLOS ONE. 8 (7): e69531. Bibcode:2013PLoSO...869531O. doi:10.1371/journal.pone.0069531. ISSN 1932-6203. PMC 3729951. PMID 23936037.
  39. ^ Welling, Lisa L. M.; Jones, Benedict C.; DeBruine, Lisa M.; Smith, Finlay G.; Feinberg, David R.; Little, Anthony C.; Al-Dujaili, Emad A. S. (1 November 2008). "Men report stronger attraction to femininity in women's faces when their testosterone levels are high". Hormones and Behavior. 54 (5): 703–708. doi:10.1016/j.yhbeh.2008.07.012. PMID 18755192. S2CID 205803606.
  40. ^ Bird, Brian M.; Welling, Lisa L. M.; Ortiz, Triana L.; Moreau, Benjamin J. P.; Hansen, Steve; Emond, Michael; Goldfarb, Bernard; Bonin, Pierre L.; Carré, Justin M. (1 September 2016). "Effects of exogenous testosterone and mating context on men's preferences for female facial femininity". Hormones and Behavior. 85: 76–85. doi:10.1016/j.yhbeh.2016.08.003. PMID 27511452. S2CID 4130150.
  41. ^ Puts, David A.; Jones, Benedict C.; DeBruine, Lisa M. (1 March 2012). "Sexual Selection on Human Faces and Voices". The Journal of Sex Research. 49 (2–3): 227–243. CiteSeerX 10.1.1.699.7560. doi:10.1080/00224499.2012.658924. ISSN 0022-4499. PMID 22380590. S2CID 27040803.
  42. ^ "How Does Evolution Occur?". necsi.edu.
  43. ^ a b c d e f g h i j k l Puts, D., Carrier, D., and Rogers, A.R. (in press). Contest competition for mates and the evolution of human males. In: Handbook of Human Mating. Buss, D.M. and Durkee, P., eds. Oxford University Press.[ISBN missing][page needed]
  44. ^ Mitani, J. C.; Gros-Louis, J.; Richards, A. F. (June 1996). "Sexual Dimorphism, the Operational Sex Ratio, and the Intensity of Male Competition in Polygynous Primates". The American Naturalist. 147 (6): 966–980. doi:10.1086/285888. ISSN 0003-0147. S2CID 84857807.
  45. ^ Abe, T (1 October 2003). "Sex differences in whole body skeletal muscle mass measured by magnetic resonance imaging and its distribution in young Japanese adults". British Journal of Sports Medicine. 37 (5): 436–440. doi:10.1136/bjsm.37.5.436. ISSN 0306-3674. PMC 1751351. PMID 14514537.
  46. ^ Hoffman, Steven G.; Schildhauer, Mark P.; Warner, Robert R. (July 1985). "The Costs of Changing Sex and the Ontogeny of Males Under Contest Competition for Mates". Evolution. 39 (4): 915–927. doi:10.2307/2408690. ISSN 0014-3820. JSTOR 2408690. PMID 28561353.
  47. ^ Archer, John (December 2004). "Sex Differences in Aggression in Real-World Settings: A Meta-Analytic Review". Review of General Psychology. 8 (4): 291–322. doi:10.1037/1089-2680.8.4.291. ISSN 1089-2680. S2CID 26394462.
  48. ^ Ellis, Lee; Hershberger, Scott; Field, Evelyn; Wersinger, Scott; Pellis, Sergio; Geary, David; Palmer, Craig; Hoyenga, Katherine; Hetsroni, Amir; Karadi, Kazmer (13 May 2013). Sex Differences. doi:10.4324/9780203838051. ISBN 978-0203838051.
  49. ^ Ryan, Michael J. (3 February 1995). "Offsetting Advantages: Sexual Selection. Malte Andersson. Princeton University Press, Princeton, NJ, 1994. 599 pp". Science. 267 (5198): 712–713. doi:10.1126/science.267.5198.712. ISSN 0036-8075. S2CID 220098656.
  50. ^ Archer, John (August 2009). "Does sexual selection explain human sex differences in aggression?". Behavioral and Brain Sciences. 32 (3–4): 249–266. doi:10.1017/S0140525X09990951. ISSN 0140-525X. PMID 19691899.
  51. ^ Smith, John Maynard; Parker, G.A. (February 1976). "The logic of asymmetric contests". Animal Behaviour. 24 (1): 159–175. doi:10.1016/s0003-3472(76)80110-8. ISSN 0003-3472. S2CID 53161069.
  52. ^ Hodges-Simeon, Carolyn R.; Gaulin, Steven J. C.; Puts, David A. (December 2010). "Different Vocal Parameters Predict Perceptions of Dominance and Attractiveness". Human Nature. 21 (4): 406–427. doi:10.1007/s12110-010-9101-5. ISSN 1045-6767. PMC 2995855. PMID 21212816.
  53. ^ Feinberg, D.R.; Jones, B.C.; Little, A.C.; Burt, D.M.; Perrett, D.I. (March 2005). "Manipulations of fundamental and formant frequencies influence the attractiveness of human male voices". Animal Behaviour. 69 (3): 561–568. doi:10.1016/j.anbehav.2004.06.012. S2CID 205510863.
  54. ^ Puts, David Andrew; Gaulin, Steven J.C.; Verdolini, Katherine (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior. 27 (4): 283–296. doi:10.1016/j.evolhumbehav.2005.11.003. S2CID 32562654.
  55. ^ a b Puts, David A.; Hill, Alexander K.; Bailey, Drew H.; Walker, Robert S.; Rendall, Drew; Wheatley, John R.; Welling, Lisa L. M.; Dawood, Khytam; Cárdenas, Rodrigo; Burriss, Robert P.; Jablonski, Nina G.; Shriver, Mark D.; Weiss, Daniel; Lameira, Adriano R.; Apicella, Coren L. (27 April 2016). "Sexual selection on male vocal fundamental frequency in humans and other anthropoids". Proceedings of the Royal Society B: Biological Sciences. 283 (1829): 20152830. doi:10.1098/rspb.2015.2830. ISSN 0962-8452. PMC 4855375. PMID 27122553.
  56. ^ Fessler, Daniel M.T.; Tiokhin, Leonid B.; Holbrook, Colin; Gervais, Matthew M.; Snyder, Jeffrey K. (January 2014). "Foundations of the Crazy Bastard Hypothesis: Nonviolent physical risk-taking enhances conceptualized formidability". Evolution and Human Behavior. 35 (1): 26–33. doi:10.1016/j.evolhumbehav.2013.09.003. S2CID 9657298.
  57. ^ Craig, Belinda M.; Nelson, Nicole L.; Dixson, Barnaby J. W. (May 2019). "Sexual Selection, Agonistic Signaling, and the Effect of Beards on Recognition of Men's Anger Displays". Psychological Science. 30 (5): 728–738. doi:10.1177/0956797619834876. ISSN 0956-7976. PMID 30908116. S2CID 85514733.
  58. ^ Guthrie, R. (1970). Evolution of human threat display organs. Evolutionary Biology, 4, 257–302.
  59. ^ Hill, Alexander K.; Hunt, John; Welling, Lisa L.M.; Cárdenas, Rodrigo A.; Rotella, Michelle A.; Wheatley, John R.; Dawood, Khytam; Shriver, Mark D.; Puts, David A. (September 2013). "Quantifying the strength and form of sexual selection on men's traits". Evolution and Human Behavior. 34 (5): 334–341. doi:10.1016/j.evolhumbehav.2013.05.004.
  60. ^ Kordsmeyer, Tobias L.; Hunt, John; Puts, David A.; Ostner, Julia; Penke, Lars (July 2018). "The relative importance of intra- and intersexual selection on human male sexually dimorphic traits". Evolution and Human Behavior. 39 (4): 424–436. doi:10.1016/j.evolhumbehav.2018.03.008. S2CID 150154211.
  61. ^ Wolff, S. E., & Puts, D. A. (2010). "Vocal masculinity is a robust dominance signal in men". Behavioral Ecology and Sociobiology, 64(10), 1673–1683. doi:10.1007/s00265-010-0981-5
  62. ^ a b Carrier, David R. (18 May 2011). "The Advantage of Standing Up to Fight and the Evolution of Habitual Bipedalism in Hominins". PLOS ONE. 6 (5): e19630. Bibcode:2011PLoSO...619630C. doi:10.1371/journal.pone.0019630. ISSN 1932-6203. PMC 3097185. PMID 21611167.
  63. ^ Darwin, Charles (1871). The descent of man, and selection in relation to sex. London: J. Murray. doi:10.5962/bhl.title.2092.
  64. ^ Thorpe, S.K.S.; Crompton, R.H.; Wang, W.J. (8 February 2004). "Stresses Exerted in the Hindlimb Muscles of Common Chimpanzees (Pan troglodytes) during Bipedal Locomotion". Folia Primatologica. 75 (4): 253–265. doi:10.1159/000078937. ISSN 0015-5713. PMID 15316153. S2CID 20869474.
  65. ^ Marzke, M. W.; Wullstein, K. L.; Viegas, S. F. (November 1992). "Evolution of the power ("squeeze") grip and its morphological correlates in hominids". American Journal of Physical Anthropology. 89 (3): 283–298. doi:10.1002/ajpa.1330890303. ISSN 0002-9483. PMID 1485637.
  66. ^ Napier, John (November 1962). "Fossil Hand Bones from Olduvai Gorge". Nature. 196 (4853): 409–411. Bibcode:1962Natur.196..409N. doi:10.1038/196409a0. ISSN 0028-0836.
  67. ^ a b Young, Richard W. (January 2003). "Evolution of the human hand: the role of throwing and clubbing". Journal of Anatomy. 202 (1): 165–174. doi:10.1046/j.1469-7580.2003.00144.x. ISSN 0021-8782. PMC 1571064. PMID 12587931.
  68. ^ Young, Richard W. (18 March 2009). "The ontogeny of throwing and striking". Human_ontogenetics. 3 (1): 19–31. doi:10.1002/huon.200800013.
  69. ^ Plavcan, J.Michael; van Schaik, Carel P. (April 1997). "Interpreting hominid behavior on the basis of sexual dimorphism". Journal of Human Evolution. 32 (4): 345–374. doi:10.1006/jhev.1996.0096. ISSN 0047-2484. PMID 9085186.
  70. ^ Carrier, David R.; Morgan, Michael H. (February 2015). "Protective buttressing of the hominin face: Buttressing of the hominin face". Biological Reviews. 90 (1): 330–346. doi:10.1111/brv.12112. PMID 24909544. S2CID 14777701.
  71. ^ Papadatou-Pastou, Marietta; Martin, Maryanne; Munafò, Marcus R.; Jones, Gregory V. (September 2008). "Sex differences in left-handedness: A meta-analysis of 144 studies". Psychological Bulletin. 134 (5): 677–699. doi:10.1037/a0012814. ISSN 1939-1455. PMID 18729568.
  72. ^ Medland, Sarah E.; Duffy, David L.; Wright, Margaret J.; Geffen, Gina M.; Hay, David A.; Levy, Florence; van-Beijsterveldt, Catherina E.M.; Willemsen, Gonneke; Townsend, Grant C.; White, Vicki; Hewitt, Alex W.; Mackey, David A.; Bailey, J. Michael; Slutske, Wendy S.; Nyholt, Dale R. (January 2009). "Genetic influences on handedness: Data from 25,732 Australian and Dutch twin families". Neuropsychologia. 47 (2): 330–337. doi:10.1016/j.neuropsychologia.2008.09.005. ISSN 0028-3932. PMC 2755095. PMID 18824185.
  73. ^ Coren, Stanley; Halpern, Diane F. (1991). "Left-handedness: A marker for decreased survival fitness". Psychological Bulletin. 109 (1): 90–106. doi:10.1037/0033-2909.109.1.90. ISSN 1939-1455. PMID 2006231.
  74. ^ Raymond, M.; Pontier, D.; Dufour, A. B.; Møller, A. P. (22 December 1996). "Frequency-dependent maintenance of left handedness in humans". Proceedings of the Royal Society of London. Series B: Biological Sciences. 263 (1377): 1627–1633. doi:10.1098/rspb.1996.0238. ISSN 0962-8452. PMID 9025310. S2CID 11938077.
  75. ^ Richardson, Thomas; Gilman, R. Tucker (21 February 2019). "Left-handedness is associated with greater fighting success in humans". Scientific Reports. 9 (1): 15402. Bibcode:2019NatSR...915402R. bioRxiv 10.1101/555912. doi:10.1038/s41598-019-51975-3. PMC 6817864. PMID 31659217. Retrieved 12 December 2022.
  76. ^ Fillingim, R. B., King, C. D., Ribeiro-Dasilva, M. C., Rahim-Williams, B., & Riley, J. L. (2009). Sex, gender, and pain: a review of recent clinical and experimental findings. The journal of pain, 10(5), 447–485. Fitch, W. T., & Giedd, J. (1999).
  77. ^ Riley, Joseph L; Robinson, Michael E; Wise, Emily A; Myers, Cynthia D; Fillingim, Roger B (January 1998). "Sex differences in the perception of noxious experimental stimuli: a meta-analysis". Pain. 74 (2): 181–187. doi:10.1016/s0304-3959(97)00199-1. ISSN 0304-3959. PMID 9520232. S2CID 9189089.
  78. ^ Billat, Véronique L.; Demarle, Alexandre; Slawinski, Jean; Paiva, Mario; Koralsztein, Jean-Pierre (December 2001). "Physical and training characteristics of top-class marathon runners". Medicine & Science in Sports & Exercise. 33 (12): 2089–2097. doi:10.1097/00005768-200112000-00018. ISSN 0195-9131. PMID 11740304. S2CID 38838193.
  79. ^ Davies, C. T. M.; Thompson, M. W. (August 1979). "Aerobic performance of female marathon and male ultramarathon athletes". European Journal of Applied Physiology and Occupational Physiology. 41 (4): 233–245. doi:10.1007/bf00429740. ISSN 0301-5548. PMID 499187. S2CID 39782050.
  80. ^ Vugt, Mark Van; Cremer, David De; Janssen, Dirk P. (January 2007). "Gender Differences in Cooperation and Competition". Psychological Science. 18 (1): 19–23. doi:10.1111/j.1467-9280.2007.01842.x. ISSN 0956-7976. PMID 17362372. S2CID 3566509.
  81. ^ Brooks, James; Onishi, Ena; Clark, Isabelle R.; Bohn, Manuel; Yamamoto, Shinya (24 February 2021). "Uniting against a common enemy: Perceived outgroup threat elicits ingroup cohesion in chimpanzees". PLOS ONE. 16 (2): e0246869. Bibcode:2021PLoSO..1646869B. doi:10.1371/journal.pone.0246869. ISSN 1932-6203. PMC 7904213. PMID 33626062.
  82. ^ McDonald, Melissa M.; Navarrete, Carlos David; Van Vugt, Mark (5 March 2012). "Evolution and the psychology of intergroup conflict: the male warrior hypothesis". Philosophical Transactions of the Royal Society B: Biological Sciences. 367 (1589): 670–679. doi:10.1098/rstb.2011.0301. ISSN 0962-8436. PMC 3260849. PMID 22271783.
  83. ^ Wrangham, Richard W. (1999). "Evolution of coalitionary killing". American Journal of Physical Anthropology. 110 (S29): 1–30. doi:10.1002/(sici)1096-8644(1999)110:29+<1::aid-ajpa2>3.0.co;2-e. ISSN 0002-9483.
  84. ^ a b Berglund, Anders; Bisazza, Angelo; Pilastro, Andrea (August 1996). "Armaments and ornaments: an evolutionary explanation of traits of dual utility". Biological Journal of the Linnean Society. 58 (4): 385–399. doi:10.1111/j.1095-8312.1996.tb01442.x. ISSN 0024-4066.
  85. ^ Puts, David A. (May 2010). "Beauty and the beast: mechanisms of sexual selection in humans". Evolution and Human Behavior. 31 (3): 157–175. doi:10.1016/j.evolhumbehav.2010.02.005. ISSN 1090-5138.
  86. ^ Frederick, David A.; Haselton, Martie G. (August 2007). "Why Is Muscularity Sexy? Tests of the Fitness Indicator Hypothesis". Personality and Social Psychology Bulletin. 33 (8): 1167–1183. doi:10.1177/0146167207303022. ISSN 0146-1672. PMID 17578932. S2CID 2972841.
  87. ^ a b Puts, David A.; Jones, Benedict C.; DeBruine, Lisa M. (1 March 2012). "Sexual Selection on Human Faces and Voices". The Journal of Sex Research. 49 (2–3): 227–243. doi:10.1080/00224499.2012.658924. ISSN 0022-4499. PMID 22380590. S2CID 27040803.
  88. ^ Buss, David M. (March 1989). "Sex differences in human mate preferences: Evolutionary hypotheses tested in 37 cultures". Behavioral and Brain Sciences. 12 (1): 1–14. doi:10.1017/S0140525X00023992. S2CID 3807679.
  89. ^ a b Fisher, Maryanne L. (2022). "Female Intrasexual Competition". The Cambridge Handbook of Evolutionary Perspectives on Sexual Psychology: Volume 3: Female Sexual Adaptations. 3: 91–117. doi:10.1017/9781108943567.006. ISBN 9781108943567.
  90. ^ Campbell, Anne (April 1999). "Staying alive: Evolution, culture, and women's intrasexual aggression". Behavioral and Brain Sciences. 22 (2): 203–214. doi:10.1017/s0140525x99001818. PMID 11301523. S2CID 1081104.
  91. ^ a b Benenson, Joyce F.; Webb, Christine E.; Wrangham, Richard W. (2022). "Self-protection as an adaptive female strategy". Behavioral and Brain Sciences. 45: e128. doi:10.1017/S0140525X21002417. PMID 34742359. S2CID 243845886.
  92. ^ a b c d e f g h Fisher, Maryanne L.; Krems, Jaimie Arona (26 January 2023). "An Evolutionary Review of Female Intrasexual Competition". The Oxford Handbook of Human Mating: 378–C14.P201. doi:10.1093/oxfordhb/9780197536438.013.27. ISBN 978-0197536438.
  93. ^ Benenson, Joyce F. (August 2009). "Dominating versus eliminating the competition: Sex differences in human intrasexual aggression". Behavioral and Brain Sciences. 32 (3–4): 268–269. doi:10.1017/s0140525x0999046x.
  94. ^ Campbell, Anne (5 December 2013). "The evolutionary psychology of women's aggression". Philosophical Transactions of the Royal Society B: Biological Sciences. 368 (1631): 20130078. doi:10.1098/rstb.2013.0078. PMC 3826207. PMID 24167308.
  95. ^ Reynolds, Tania; Baumeister, Roy F.; Maner, Jon K. (2018). "Competitive reputation manipulation: Women strategically transmit social information about romantic rivals". Journal of Experimental Social Psychology. 78: 195–209. doi:10.1016/j.jesp.2018.03.011. S2CID 146804099.
  96. ^ Rosvall, Kimberly A. (1 November 2011). "Intrasexual competition in females: evidence for sexual selection?". Behavioral Ecology. 22 (6): 1131–1140. doi:10.1093/beheco/arr106. PMC 3199163. PMID 22479137.
  97. ^ Campbell, Anne (5 December 2013). "The evolutionary psychology of women's aggression". Philosophical Transactions of the Royal Society B: Biological Sciences. 368 (1631): 20130078. doi:10.1098/rstb.2013.0078. ISSN 0962-8436. PMC 3826207. PMID 24167308.
  98. ^ a b Fisher, Maryanne L.; Krems, Jaimie Arona (26 January 2023), "An Evolutionary Review of Female Intrasexual Competition", The Oxford Handbook of Human Mating, Oxford University Press, pp. 378–C14.P201, doi:10.1093/oxfordhb/9780197536438.013.27, ISBN 978-0-19-753643-8, retrieved 9 December 2023
  99. ^ Moore, F.R.; Law Smith, M.J.; Taylor, V.; Perrett, D.I. (May 2011). "Sexual dimorphism in the female face is a cue to health and social status but not age". Personality and Individual Differences. 50 (7): 1068–1073. doi:10.1016/j.paid.2011.01.026.
  100. ^ Puts, David A. (May 2010). "Beauty and the beast: mechanisms of sexual selection in humans". Evolution and Human Behavior. 31 (3): 157–175. doi:10.1016/j.evolhumbehav.2010.02.005.
  101. ^ a b c Dixson, Barnaby J. W. (January 2022). "Sexual Selection and the Evolution of Human Appearance Enhancements". Archives of Sexual Behavior. 51 (1): 49–55. doi:10.1007/s10508-021-01946-5. ISSN 0004-0002. PMID 33721143. S2CID 232244631.
  102. ^ Norgan, Ng (September 1997). "The beneficial effects of body fat and adipose tissue in humans*". International Journal of Obesity. 21 (9): 738–746. doi:10.1038/sj.ijo.0800473. ISSN 0307-0565. PMID 9376885. S2CID 5781207.
  103. ^ Lassek, W; Gaulin, S (January 2008). "Waist-hip ratio and cognitive ability: is gluteofemoral fat a privileged store of neurodevelopmental resources?". Evolution and Human Behavior. 29 (1): 26–34. doi:10.1016/j.evolhumbehav.2007.07.005.
  104. ^ Singh, Devendra (1993). "Adaptive significance of female physical attractiveness: Role of waist-to-hip ratio". Journal of Personality and Social Psychology. 65 (2): 293–307. doi:10.1037/0022-3514.65.2.293. ISSN 1939-1315. PMID 8366421.
  105. ^ Hochberg, Ze'ev; Gawlik, Aneta; Walker, Robert S (December 2011). "Evolutionary fitness as a function of pubertal age in 22 subsistence-based traditional societies". International Journal of Pediatric Endocrinology. 2011 (1): 2. doi:10.1186/1687-9856-2011-2. ISSN 1687-9856. PMC 3159136. PMID 21860629.
  106. ^ Lassek, William D.; Gaulin, Steven J. C. (1 October 2018). "Do the Low WHRs and BMIs Judged Most Attractive Indicate Higher Fertility?". Evolutionary Psychology. 16 (4): 147470491880006. doi:10.1177/1474704918800063. ISSN 1474-7049. PMC 10480809. PMID 30296846. S2CID 52941981.
  107. ^ Mahoney, Sean M.; Reudink, Matthew W.; Contina, Andrea; Roberts, Kelly A.; Schabert, Veronica T.; Gunther, Emily G.; Covino, Kristen M. (March 2022). "A tail of plumage colouration: disentangling geographic, seasonal and dietary effects on plumage colour in a migratory songbird". Journal of Avian Biology. 2022 (3). doi:10.1111/jav.02957. ISSN 0908-8857.
  108. ^ Loyau, Adeline; Jalme, Michel Saint; Sorci, Gabriele (September 2005). "Intra- and Intersexual Selection for Multiple Traits in the Peacock ( Pavo cristatus )". Ethology. 111 (9): 810–820. Bibcode:2005Ethol.111..810L. doi:10.1111/j.1439-0310.2005.01091.x. ISSN 0179-1613.
  109. ^ Carmen, Rachael A.; Guitar, Amanda E.; Dillon, Haley M. (June 2012). "Ultimate Answers to Proximate Questions: The Evolutionary Motivations behind Tattoos and Body Piercings in Popular Culture". Review of General Psychology. 16 (2): 134–143. doi:10.1037/a0027908. ISSN 1089-2680. S2CID 8078573.
  110. ^ Haselton, Martie G.; Mortezaie, Mina; Pillsworth, Elizabeth G.; Bleske-Rechek, April; Frederick, David A. (January 2007). "Ovulatory shifts in human female ornamentation: Near ovulation, women dress to impress". Hormones and Behavior. 51 (1): 40–45. doi:10.1016/j.yhbeh.2006.07.007. PMID 17045994. S2CID 9268718.
  111. ^ Puts, David A.; Bailey, Drew H.; Cárdenas, Rodrigo A.; Burriss, Robert P.; Welling, Lisa L. M.; Wheatley, John R.; Dawood, Khytam (1 January 2013). "Women's attractiveness changes with estradiol and progesterone across the ovulatory cycle". Hormones and Behavior. 63 (1): 13–19. doi:10.1016/j.yhbeh.2012.11.007. ISSN 0018-506X. PMID 23159480. S2CID 32877653.
  112. ^ Catena, Tikal M.; Simmons, Zachary L.; Roney, James R. (September 2019). "Do women's faces become more attractive near ovulation?". Hormones and Behavior. 115: 104560. doi:10.1016/j.yhbeh.2019.07.008. PMID 31310761. S2CID 197421994.
  113. ^ Gangestad, Steven W; Thornhill, Randy (7 May 2008). "Human oestrus". Proceedings of the Royal Society B: Biological Sciences. 275 (1638): 991–1000. doi:10.1098/rspb.2007.1425. ISSN 0962-8452. PMC 2394562. PMID 18252670.
  114. ^ a b Manning, John (2009). The Finger Ratio. Faber & Faber. ISBN 978-0571215409.
  115. ^ MacKintosh, J. (2001). "The antimicrobial properties of melanocytes, melanosomes and melanin and the evolution of black skin". Journal of Theoretical Biology. 211 (2): 101–113. Bibcode:2001JThBi.211..101M. doi:10.1006/jtbi.2001.2331. PMID 11419954.
  116. ^ Kirchweger, Gina (1 February 2001). "The Biology of . . . Skin Color". Discover. Retrieved 31 March 2015.
  117. ^ Rogers, Alan R.; Iltis, David; Wooding, Stephen (2004). "Genetic Variation at the MC1R Locus and the Time since Loss of Human Body Hair". Current Anthropology. 45: 105–108. doi:10.1086/381006. S2CID 224795768.
  118. ^ a b Jablonski, Nina G.; Chaplin, George; Chaplin (2000). "The evolution of human skin coloration" (PDF). Journal of Human Evolution. 39 (1): 57–106. doi:10.1006/jhev.2000.0403. PMID 10896812. Archived from the original (PDF) on 24 March 2003.
  119. ^ Elias, Peter M; Menon, Gapinathan; Wetzel, Bruce J; Williams, John (Jack) W (2010). "Barrier Requirements as the Evolutionary "Driver" of Epidermal Pigmentation in Humans". American Journal of Human Biology. 22 (4): 526–537. doi:10.1002/ajhb.21043. PMC 3071612. PMID 20209486.
  120. ^ Jablonski, N. G.; Chaplin, G. (2010). "Colloquium Paper: Human skin pigmentation as an adaptation to UV radiation". Proceedings of the National Academy of Sciences. 107 (Suppl 2): 8962–8968. Bibcode:2010PNAS..107.8962J. doi:10.1073/pnas.0914628107. PMC 3024016. PMID 20445093.
  121. ^ Juzeniene, Asta; Setlow, Richard; Porojnicu, Alina; Steindal, Arnfinn Hykkerud; Moan, Johan (2009). "Development of different human skin colors: A review highlighting photobiological and photobiophysical aspects". Journal of Photochemistry and Photobiology B: Biology. 96 (2): 93–100. doi:10.1016/j.jphotobiol.2009.04.009. PMID 19481954.
  122. ^ Frost, P. (2008). "Sexual selection and human geographic variation" (PDF). Journal of Social, Evolutionary, and Cultural Psychology. 2 (4): 169–191. doi:10.1037/h0099346. Archived from the original (PDF) on 25 April 2012.
  123. ^ Madrigal, Lorena; Kelly, William (2007). "Human skin-color sexual dimorphism: A test of the sexual selection hypothesis". American Journal of Physical Anthropology. 132 (3): 470–482. doi:10.1002/ajpa.20453. ISSN 0002-9483. PMID 16685728. Our analysis failed to support the prediction of a positive correlation between increasing distance from the equator and increased sexual dimorphism. We found no evidence in support of the sexual selection hypothesis.
  124. ^ Lazaridis, Iosif (8 August 2022). "The genetic history of the Southern Arc: a bridge between West Asia and Europe" (PDF). Science. 377 (6609). NIH Public Access: eabm4247. doi:10.1126/science.abm4247. PMC 10064553. PMID 36007055. Retrieved 22 February 2024. page 24 of supplemental data document: "The frequency of these traits could have been shaped by migration or by selection, but is more complex than simplistic stories, e.g., of these traits arising due to sexual selection in boreal hunter-gatherers(75)... " (citation 75 is Frost's study)
  125. ^ Cunningham, M.R.; Roberts, A.R.; Barbee, A.P.; Druen, P.B.; Wu, C-H. (1995). "Their ideas of beauty are, on the whole, the same as ours": consistency and variability in the cross-cultural perception of female physical attractiveness". Journal of Personality and Social Psychology. 68 (2): 267. doi:10.1037/0022-3514.68.2.261. All groups of judges made more positive ratings of the Asian and Hispanic targets compared with the Black and White targets.
  126. ^ Stephen, Ian D.; Salter, Darby L. H.; Tan, Kok Wei; Tan, Chrystalle B. Y.; Stevenson, Richard J. (3 July 2018). "Sexual dimorphism and attractiveness in Asian and White faces". Visual Cognition. 26 (6): 442–449. doi:10.1080/13506285.2018.1475437. ISSN 1350-6285. S2CID 150264484.
  127. ^ Russell, Richard (20 November 2012). "A Sex Difference in Facial Contrast and its Exaggeration by Cosmetics". Perception. 38 (8): 1211–1219. doi:10.1068/p6331. PMID 19817153. S2CID 136762. Retrieved 22 February 2024.
  128. ^ Geoffrey Miller, The Mating Mind, p.111; published 2001
  129. ^ Klasios, J. (2013). "Cognitive traits as sexually selected fitness indicators". Review of General Psychology. pp. 428–442.

Further reading[edit]