Origins Of Human Sexuality Essay, Research Paper

Soc. 471

The Origins of

Human Sexuality

Daly & Wilson Theory:

In their book Homicide, Martin Daly and Margo Wilson put forth a theory that challenges human societies common notion of human sexuality. They do this in an attempt to bring about a better understanding of homicide and male aggressiveness. According to Daly and Wilson, males instigate the overwhelming majority of “dangerous altercations” and they contend that this is due to “status competition.” Status competition is the idea that males must aggressively compete for sexual access to females in order to pass on their genes.

Daily and Wilson cite the work of Charles Darwin, who in 1859 published a famous work on the theory of natural selection. The concepts presented in his book were later elaborated in his second work, which dealt with the concept of “sexual selection.” Sexual selection according to Darwin’s theory, was based on the observation that not all evolutionary adaptations serve a survival function; that in many cases, “a trait might be penalized by ‘natural’ selection and yet win out by ‘sexual’ selection.” Darwin argued that surviving and living a long life did not ensure reproductive success and therefore an animal’s goal of longevity is secondary to its goal of passing on its genes through procreation. These ideas form the foundation for Martin Daly and Margo Wilson’s theory.

Daly and Wilson also refer to the research done by a British geneticist named A.J. Bateman to strengthen their arguments for the idea of status competition. Bateman’s research focused on lab experiments done on Drosophila or fruit flies. The experiments consisted of taking fruit flies with “distinct genetic markers” and placing them in jars. It was made sure that each jar contained an equal number of males and females. The jars were then put under observation. Bateman noticed that there was a difference when he compared the reproductive success of the females to the success of the males. According to Bateman’s research a female fruit fly could expect to have about 60 to 80 offspring regardless of the number of male fruit flies she copulated with. However the reproductive success of a male fruit fly depended on the number of females it had mated with. “Those who copulated with one female produced about 40 young, those who copulated with two produced about 80, and so forth.” Bateman also notes the difference each sex of fruit fly could expect to produce-females could expect to have about the same amount of offspring, whereas some males had a great number of offspring (far above average) while others failed to produce at all. In general males had a much wider range of potential offspring and therefore the males had potential for great success or complete failure. These finding prompted Bateman to conclude “selection would produce tactics of male mating competition, as well as an undiscriminatory eagerness in the males and a discriminatory passivity in the females.”

Daly and Wilson claim that the conclusions made by Batman on fruit flies reproductive condition also hold true for Homo sapiens. According to Daly and Wilson, human females have a lower maximum number of offspring they can produce when compared to males. Females also have a much smaller range of mating outcomes when compared to males. Daly and Wilson cite the work of Robert Trivers to corroborate this idea. According to Trivers, the key to understanding the difference between male and female fruit flies, as well as humans, is by determining the amount of parental investment given by either sex. According to the their theory females make the largest parental investment and consequently can not expect to increase her chances of passing on her genes by mating indiscreetly. Women typically must “invest” time in pregnancy as well as feeding the child (Female fruit flies investment comes in the form of producing eggs). Whereas a male increases his chances of passing on his genes with each female he mates with, due to his relatively small parental investment. Because male success is determined by the amount of access he has to females, males must compete for access to females much more than females must compete for access to males. This competition, according to the theory, makes the “winners win bigger, and the losers…more likely to be total losers.”

In their discussion of parental investment Daly and Wilson specify three different types of division. Larger females and smaller males characterize the first category called polyandry. In polyandrous species we see males making the larger parental investment, females being more combative, and males tending to out live their female counterparts. The second category is known as a monogamous breeding system. In this system the male and female parental investments are identical, the number of offspring each sex can have is identical and the fitness variances are equal. In monogamous species the male and female tend to be indistinguishable in that they are often the same size and carry the same markings. Monogamous species also have nearly the life expectancy. The final category is known as polygamy. Polygamy is a system in which the female makes the biggest parental investment. In polygamous species the male is often larger and more combative than the female and tends to live a shorter life. According to Daly and Wilson humans best fit into this last group. According to Daly and Wilson humans “are the products of a mild but sustained polygynous competition.”

The Evolution of Desire

In his book The Evolution of Desire, David M. Buss submits a unified theory of human mating. He does this primarily through explaining how humans have evolved specific traits that have rendered some humans more adequate at handling the competition for scarce mating partners, and therefore contributed to their preservation. It is these adaptations, Buss argues, that make human mating strategies what they are today. In his book Buss describes the very origins of human mating as well as the common practices utilized today and draw parallels between the two. His claim is that though the human condition has changed overtime, humans still possess the same instincts and traits, which rendered their ancestors successful in producing offspring. As evidence Buss uses a study he conducted which included fifty collaborators from thirty-seven cultures from six continents and five islands. The study surveyed a total of 10,047 people world wide and included people from the ages of fourteen through seventy years old.

Buss makes his argument for sexual selection and its effect on human’s mating strategy by describing the evolutionary roots for which humans evolved. Buss strengthens his argument, by describing what it is men and women want from a mate and how each desire has an evolutionary foundation. Next Buss strengthens his argument by describing the phenomenon known as the Coolidge effect. Lastly, Buss substantiates his argument by describing the sexual behavior exhibited by male and female homosexuals.

Humans, according to Buss, have developed unconscious patterns that have been adapted overtime to solve specific mating problems. Buss states that “all of us descend from a long and unbroken line of ancestors who competed successfully for desirable mates, attracted mates who were reproductively valuable, retained mates long enough to reproduce, fended off interested rival, and solved the problems that could have impeded reproductive success.” Buss argues that these unconscious patterns have shaped what it is today that we consider human sexual desire. The origins of this desire can be traced to the competitive nature of securing mates in order that we pass on our genes.

Men and women want entirely different things, according to Buss. Buss’s claim is that the problems faced by the two sexes are different and therefore the unconscious patterns evolved for men and women would necessarily have to be different. Buss argues that women make a larger parental investment and therefore must look for mates who are willing to commit to a long-term relationship. “A man in human evolutionary history could walk away from a casual coupling having lost only a few hours of time. His reproductive success was not seriously compromised. A woman in evolutionary history could also walk away from a casual encounter, but if she got pregnant as a result, she bore the costs of that decision for months, years, and even decades afterward.” A woman therefore must be very particular about who she chooses as a mate. A woman must first consider a man’s resources. According to Buss, men with a high level of resources are better able at providing food, shelter and fending off rivals. The best indicator today for evaluating a man’s resources is economic assets. In his world wide study, women overall “value financial resources about 100 percent more than men do or roughly twice as much.” Another indicator of a man’s resources is his social status. Men high in social status are more likely to hold power and privilege, an invaluable resource which can often be passed down to descendants. In the world wide study women tended to place more importance in social status than men in prospective mates. The study also showed that men tend to marry downward whereas women tended to prefer a mate of higher social status. Age is also another indicator of a man’s resources due to men generally acquiring higher wages as they age. And again we see in the worldwide study a general tendency for women to prefer men “who are roughly three and a half years older.” Buss also claims that women have acquired a preference for men who show signs of ambition, intelligence and stability. In Buss’s worldwide study women rated each of these traits as more important than men did. Women also show a propensity for men who show signs of good health, strength and athletic prowess. Buss claims that this is due to evolution favoring those women who choose men who were successful as hunters and defenders of their family. Good health was also important due to the chance that a male could pass on genes for poor health to her young. Finally, women desire a high level of commitment from a mate. This ensures that a male’s resources are channeled to his family and will not be channeled elsewhere.

What males’ desire in a mate is immensely different from females and is often juxtaposed. “Since all an ancestral man needed to do to reproduce was to impregnate a woman, casual sex without commitment would have sufficed for him.” However, Buss argues, that men committing to a relationship also served an adaptive advantage. For one, women often require a male’s commitment before agreeing to sex and secondly, by committing to a monogamous relationship a male better ensures the health and well being of his offspring. Men, according to Buss, search out women who have the capacity for bearing many children. Men, consequently, developed a basis for which to judge a female’s reproductive capacity. One way a man judges a female’s reproductive value is age. “Youth is a critical cue…” to a woman’s reproductive value. As a Woman’s ability to produce children declines with the onset of old age so does her desirability. Buss’s thirty-seven-culture study showed that on average men desire wives that are approximately 2.5 years younger than they are. Men also look to physical beauty and body shape as a cue to a woman’s reproductive capacity. According to Buss, men prefer women who show evidence of “health and youth.” “Men who failed to prefer qualities that signal high reproductive value-men who preferred to marry gray-haired women lacking in smooth skin and firm muscle tone-would have left fewer offspring, and their line would have died out.” Buss cites as evidence a recent study that generated composites of the human face and asked men to judge which faces they believed to be the most attractive. Men repeatedly choose the faces that were the most symmetrical. Symmetry, according to biologists, is a sign of good health and youth, which would explain why men judged those faces with highest levels of symmetry as the most beautiful. Body shape also provides an important clue to the reproductive value of a woman. Men from different cultures tend to prefer different body types from thin to stout but one preference tends to remain the same: the waist to hip ratio. Buss cites a study that found that men tend to prefer, regardless of culture, a woman with a hip to waist ratio of 0.70. Buss claims that this ratio is an important clue to a woman’s reproductive value because higher ratios tend to indicate that a woman is pregnant.

The search for casual sex is a trait that men have adapted due to men increasing their chances of reproductive success by mating with multiple females. Buss demonstrates this by pointing to a phenomenon called the Coolidge effect. The Coolidge effect is a “tendency of males to be sexually rearoused upon the presentation of novel females, giving them a further impulse to gain sexual access to multiple women. As evidence for this occurrence, Buss cites research done by Kinsey which found that 50 percent of males and only 26 percent of female had extramarital affairs. A similar study done by another scientist yielded even more surprising results. According to the “Hunts” survey, 41 percent of males and only 18 percent of women engaged in extramarital affairs. These studies along with others indicate: men far more than women pursue novelty in their sexual relationships.

Buss claims that the behaviors of homosexuals serve to strengthen his arguments for the evolutionary basis of sex differences in the desire for mates. Homosexual men, according to buss exhibit the same evolutionary traits as heterosexual males. Both homosexual and heterosexual males place great importance on the appearance of their partners. They also both attach immense weight to a potential partner’s age. Lesbians however, like heterosexual females, place little importance on a companion’s physical appearance. Buss points to a study that seems to offer evidence to substantiate this claim. According to one investigation, which asked what qualities an individual desired in a mate, heterosexual women and lesbian women alike tended to place “little emphasis on physical appearance, with only 19.5 percent of the heterosexual women and 18 percent of the lesbians mentioning this quality. Whereas heterosexual men noted physical beauty as a quality they seek in a mate 48 percent of the time and homosexual men 29 percent of the time.” There is also evidence for Buss’s claim in the number of sexual partners had by both homosexuals and lesbians. Homosexuals again tend to exhibit the same quality as heterosexual men preferring many sex partners. “The evidence suggests that when men are unconstrained by the courtship and commitment requirements typically imposed by women, they freely satisfy their desires for casual sex with a variety of partners.” Contrary to men, lesbian women, much like heterosexual women, tended to “settle into intimate, lasting, committed relationships.” This evidence seems to suggest that men and women have evolved unconscious desires that do not change with sexual preference. Men and women tend to exhibit their expected sexual behavior regardless of their sexual preference.

Conclusion

The two books examined in this paper, Martin Daly and Margo Wilson’s Homicide and David M. Buss’s The Evolution of Desire, suggest that human mating strategies have an evolutionary basis. The book written by Martin Daly and Margo Wilson supplies the theoretical groundwork and the book written by David M. Buss gives validity and empirical support for the theory. The two books make a strong scientific argument for evolutionary adaptations as the most crucial element to understanding human sexuality and desire. According to this argument, the key to understanding human sexuality lies in the evolutionary origin of our species.