The evolution of sex is the hardest problem in evolutionary biology.
-John M. Smith
One of the most curious problems of the human condition pertains to sexual diversification amongst men and women. It is apparent that the physiology of both sexes differs to some degree. Both men and women have different reproductive organs yet, there seems to be a lot more going on underneath the surface. Why do men find women attractive? Why do women find men attractive? Mating rituals have changed over the course of history, but has basic human biology?
The Truth is Stranger with Friction
Sex isn’t the only way of reproduction but it’s what humans ended up with. The reasoning behind this, sexual intercourse is crucial for staving off parasitic invasion. In evolutionary terms, sexual intercourse allows for diversification of genes, which are combined during reproduction. This combination of genes allows for greater diversification and a better chance of combating microscopic intruders that don’t have time to adapt. There is ample evidence for this across many sexually reproducing species (Zimmer, 2001).
Man on Top
Men rule. Well, at least they think they do. Throughout the greatest epochs of history, humans have never recorded a matriarchal society. There have only been those dominated by males. This shouldn’t come as a surprise to anyone that has even heard the word history. Think about the word history or his-story. The word comes from the Greek word historia which is a derivative of the word historein which means “to inquire.” Unfortunately for women, the etymology of the word keeps rooting itself further as historein derivative is formed from “history” or “learned man.” So obviously man has dominated certain aspects of language. But does this mean they have dominated humanity sexually?
In short, yes. Men have been genetically qualified to run around on the Savannah and acquire the capital to help diversify their genetics (evolutionarily speaking). For most mammals, the male becomes the king. Paul Ehrlich qualifies this with his research in apes. Gorilla males are almost twice as large as their female counterparts and exhibit larger canine teeth. This is tell-tale of male dominated societies where the males vie for access to the most plentiful harem of women (177) and is commonly referred to as Sexual Dimorphism, a theory whereby the size of a male is a measurement of sexual selection for mates. Ehrlich goes on to transpose this theory into a more human aspect. Homo erectus was the first to show a closer dynamism between human ancestry and their contemporary. The size differences were closer to humans of today (about 15-20 percent) which is probably due to selection that aimed to reduce battles over dominance or a perhaps a result of growing intelligence used to jockey for positioning in mating hierarchies.
So then, are women more likely to be attracted to men that fight in the UFC rather than paint pictures and gather flowers? Fear not poets and future laureates of the Nobel Prize, all is not lost. It seems that though size is advantageous for men to dominate women, bigger isn’t better and certainly not always in charge.
It’s Not the Size of the Jaw Line, it’s the Motion in the Evolutionary Environment of Adaptation
What women want; it is a question that men have tried to solve for centuries. Leave it to dull scientific instrumentation to offer one of the best answers.
Yes, women seem to be the more complicated sex. This is all in a fine attempt by Mother Nature to ensure only the best genes get passed on. If Mother Nature had a direct line, she would receive a lot of correspondents explaining to her of countless failures. But Mother Nature still persists and it’s the thought that counts and here are a few thoughts as to how women vary from men when choosing a potential partner.
Women have it much more difficult than men. Choosing a mate can be a bigger decision for a woman than choosing career paths or even the type of mortgage they will be fixed at for the next thirty years. After all, the job, even if it turns out to be less than spectacular, can be exchanged for a new one. A house with a fixed mortgage can always be sold. A child that springs forth from a relationship cannot however and this is a weighty idea. Nine months of gestation as well as possible decades thereafter are needed to rear children. A man doesn’t have to put forth as much capital as a woman. Besides the obvious outside resources, a woman must put forth an exorbitant amount of physical capital. And because humans and their reproductive organs have shelf lives, the choice between the stud and the dud could be a matter of life and death.
For starters, women are attracted to a very important part of human physical appearance. This is facial appearance and it differs for men and women. For women, Levay and Valente argue that there are many variables in the attractiveness of faces. The four factors that most cognitive and Evolutionary Psychologists are concerned with are left-right symmetry, averageness, masculinity-femininity and colloquially put, babyfaceness.
Just as animals look for symmetry in their mates, so do humans. The more symmetrical a person’s face is, the more attractive they are to others (Grammer and Thornhill, 1994). Experiments that have subjects rate the attractiveness of people in photos show that the most symmetrical faces win (Scheib et al., 1999). Facial symmetry can divulge details about a persons’ health as the same genetic instructions account for both sides of the body. If the development is halted or misguided, a high degree of Fluctuating Asymmetry can occur. This term refers to the change in the symmetrical features of the body when a variable such as a parasite is introduced. Fluctuating Asymmetry is a signal that there were no major upsets during development, such as infection or traumatic illness. Symmetrical qualities help deduce susceptibility to disease. Humans with better symmetrical features were found to suffer less major diseases such as schizophrenia, extremely premature birth, and retardation amongst other physical and psychological stressors (Shackelford and Larsen, 1997).
Women also look at other facial cues such as jaw width, lip size, chin size and amount of facial hair. What complicates this is the fact that the preferences for these features change during the female menstrual cycle. Women are more likely to prefer men of masculine features (larger jaw, chin and supra-occipital ridgeline) during ovulation (Penton-Voak and Perrett, 2000; Johnston et al., 2001). The idea is that women may be primed to venture forth and sniff out “good genes” or rather, ones that show physical superiority, during times of fertility. Women conversely find neo-natal features ideal when ovulation is not occurring. Wide-eyes and smooth, hairless skin are attributes of a gentler persona and heavily linked to infancy. Women look for these features in men when infertile as they are indicators of a long-term mate who will not be straying away from home in search of other potential sex partners (Penton, Voek 1999).
There are other features that women find attractive in men. The term “desperation is a stinky cologne” is validated in the world of evolution. Margo Wilson and Martin Daly of McMaster University in Canada have studied jealousy across cultures and concluded that is universally human. No culture can be seen to exist without but the consequences are usually the same. In his chapter in The Red Queen (1993), Matt Ridley states that jealousy is espoused from low self-esteem; a generally negative trait in pair bond selections.
“Jealousy shows low self-esteem, they say, and emotional dependency. Indeed it does, and that is exactly what the evolutionary theory would predict. A man held in low esteem by his wife is exactly the kind of person in danger of being cuckolded, for she has the motive to seek a better father for her children” (237).
Ridley conjectures that women are always looking for the best fathers for their children and may even look to outside sources for genetic material, all the while having the current partner believe he is raising his own flesh and blood. He goes on to state that though polygamy is rare in hunter-gatherer societies, adultery however, is everywhere (229).
Concealed ovulation can ensure that a child’s true DNA is not discovered. Cuckoldry is thus able to conceal itself at least, until the child develops a strange compulsion to deliver milk to neighbors’ doors. As humorous as this scenario is, the advantage of concealed ovulation is that the woman can get the more sought after genetics with a father more likely to give more resources in raising the child. Even more interesting is that Baker and Bellis found women retained more sperm when they went greater lengths without sex. Furthermore, the duo found non-faithful women to have high-retention orgasms with extra-marital lovers 70 percent of the time. The unfaithful women in these studies only achieved high-retention orgasms 40 percent of the time with their partner whom they claimed loyalty toward. It is of interest to note that these high-retention orgasms occurred only 55 percent of the time in relationships with faithful women.
Are women doomed to try and mate at different times with multiple partners? Not necessarily. As mentioned before with male jealousy, other factors in a relationship can determine a woman’s adulterous choices. The female race therefore is not doomed to a life paralleling day-time dramas. However, consideration must be given to this these conflicts. Though the concept of adultery arose when rock music was in its literal form, it still pervades today. Infidelity is a vestige of humanity’s ancestral past.
Waist Not, Want Not
Though male preference for sexual selection in females seems to be less complicated, there are some interesting differences to consider for the Y chromosome.
Human males have been found to enjoy not slender women but slender waists. The coveted “Waist-to-Hip-Ratio” has an important influence on sexual desire. Because women store fat in the areas of their hips after puberty, their waist is smaller, giving the appearance of the hour-glass figure. A waist-to-hip ratio of 0.7-0.9 is found to be the ticket to drive men wild (Levay, 222-223). These ratios have held up across cultures as well. The pre-conceived notion that larger breasts increased attractiveness was dismissed and though men did prefer larger than average breasts, women’s estimation on what men found insatiable was far from the mark (Thompson, Tantleff, 1992).
The Hair Essentials
Fact: hair grows fastest in 16-24 year old women. Consequently perhaps, younger women tend to wear their hair longer than older women (Hinsz et al., 2001). If you’re a man looking for a mate, it seems that younger women may be predisposed to play with their locks and men may be predisposed to detect it. The popular “hair-flip” was proved to be more prevalent in women in search of a mate (Moore, 1985). Men it turns out, love it. Long hair is a definite turn-on as Mesko and Bereczkei found in 2004. Men rated women’s youth, femininity and sexiness with long/medium length hair having a significant positive effect on these ratings. Long hair also increased men’s perception of the female subject’s overall health. Grammer (2001) backed up this claim and even hypothesized that longer hair allowed for greater pheromone dispersal. It’s no wonder that the trips to the salon for women are on average, much pricier than for men.
Human evolution has played a significant role in the rules of engagement pertaining to sex. Studies are being amassed and as more information is gathered, it is more apparent that this field is tantamount to others within psychology. Though the traits governing attraction were developed long before civilized societies had arisen, their reverberations can be felt to this day. Advertising, the internet, instant messaging and a plethora of other technological advances have augmented the original mating rituals of humanity’s past, yet the biology still pervades. Some studies seem trite or obvious while others show a counterintuitive truth. As interesting as this is, it is still in the backlogs of popular culture as businesses and individuals continue to marginalize one gender, dismissing another though compelling evidence and research points elsewhere. Future observations on how technology will change human sexual development will be interesting and may even change some popular myths about both sexes. Most importantly, what remain unchanged are the differences in attractive qualities and demands for Sexual Selection in humans through thousands of years.
References
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