Analyzing Human Mating Behavior

Trivers' (1972) theory of parental investment makes two important observations about mate selection: The gender that provides the greatest amount of parental investment will be more selective when choosing their mate. Therefore, the gender providing less parental investment will encounter more competition for potential mates.

As this applies to humans, women tend to be the more selective gender and men the more competitive. This theory appears to be very true; women tend to value traits that indicate a better aptitude for resource acquisition wich as socioeconomic status and ambition, while men generally value indicators of genetic value when choosing a mate (Feingold, 1992). However, the process of human reproduction is complicated by human's tendencies toward sexual jealousy and sexual bonding; Gray (2007) states that "People everywhere develop strong emotional ties to those toward whom they are sexually drawn" (p. 81). Because of these tendencies, the human reproduction process parallels that of the superb fairy wren; Gray (2007) observes that they are "socially but not sexually monogamous" (p. 79). The different sexual ideals of males and females conflict and, therefore, must be negotiated in order to ensure the propagation of the human race.

The nature of human reproduction is such that paternal parental investment is not essential to offspring survival. Consequently, short term mating strategies are more favorable to males; Buss and Schmitt (1993) assert that by inseminating as many females as possible while providing as little parental investment as possible, males increase the odds of forwarding their genes. In contrast, the large amount of parental investment required by females makes long term mating strategies much more favorable for them. By attaining the commitment of their male counterparts, females can capitalize on the consequent non-genetic resources provided by the male (food, protection).

This is the basis for the organization of the uman reproductive system--which is sexually polygynous but socially monogamous. One characteristic of polygyny is that "males compete with one another to mate with as many females as they can" (Gray, 2007). Statistically speaking, males maximize their reproductive potential by pursuing as many short term relationships as possible. Therefore, when pursuing short-term mates, traits such as promiscuity may be preferred because "[w]omen with an unrestricted sociosexual orientation, as compared to women with restricted sociosexual orientation, are more likely to engage in short-term relationships and obtain fewer non-genetic resources from their mates" (Provost et al., 2008). Males are much more likely to commit to a long term mating relationship if the female counterpart is seen as genetically valuable. According to Buss and Schmitt (1993), "The larger the investment in a particular mating, the fewer number of sexual partners a given man can access." Therefore, males will only make the long term commitment to a mate when it seems the reproductive cost is worth the gain. But when is the cost worth the gain?

Human males are generally more willing to provide non-genetic resources to more sexually conservative females. Geary (2005) reflects that "In species with lower levels of paternity certainty, the average level of male provisioning is lower that in species with higher levels of paternity certainty." One benefit to males practicing monogamy is a dramatically increased level of paternal certainty. According to Anderson (2006), "Cross-culturally, paternity confidence (a man's assessment of the likelihood that he is the father of a putative child) is positively associated with men's involvement with children and with investment or inheritance from paternal kin." Basically, men want to be sure that they are giving parental investment to their own offspring, rather than another male's. Any paternal discrepancy would result in the presumed father giving up his non-genetic resources at the evolutionary cost of lost opportunities for creating legitimate offspring of his own (Buss and Schmitt, 1993). This is the root of sexual jealousy in men. Consequently, "male sexual jealousy will diminsh as the age of the male's mate increases because her reproductive value decreases" (Buss et al., 1992). The female's age induced reduction in reproductive value means that it is less likely that other males would be willing to incur the risks associates with infidelity.

Females generally favor monogamy because of the non-genetic benefits of male parental investment and the relatively nonexistent cost. However, in some cases, Provost (2008) suggests that "women engage in short-term sexual relationships [...] [because] the benefits to doing so outweigh the costs." For example, if a woman is lacking in reproductive value (is not as physically attractive, etc.), promiscuity would enable her to engage in more short-term relationships and raise any resulting offspring without the benefit of paternal parental investment (similarly, a genetically inferior male may increase his reproductive value by exhibiting more willingness to provide non-genetic resources).

Alternatively, a woman already engaged in a monogamous relationship may engage in an extramarital affair if given the opportunity to mate with a male genetically superior (more attractive) to her partner; Geary (2005) notes that, "female reproductive decisions are complicated by the trade-off associates with the need to secure [...] provisioing from their social partner and the benefits associates with having their offspring sired by the most fit male in the local population." That is to say, it may be beneficial for a female to engage in an extramarital affair provided her social partner's resources could be invested in any resulting offspring. In short, females are able to "[have] it both ways by conducting affairs with genetically more valuable men while not leaving their husbands" (Ridley, 1994).

It is the drive to gain and maintain the provisioning of a male partner that is the basis for female jealousy; Buss and Schmitt (1993) observe that on an intinctual level, women perceive infidelity "as a cue to loss of investment and commitment of a man over time." The costs and benefits of long-term and short-term relationships are much different for males than for females. Males benefit significantly from short-term relationships, and the costs are extremely low. This is why, according to Buss and Schmitt (1993), "[...] short-term sexual strategies loom larger in men's strategic repertoire than in women's." Females are threatened by the possibility of male infidelity because males are more likely to be unfaithful if the reproductive value of their partner has decreased. Furthermore, any offspring resulting from his extramarital affair pose a threat to his legitimate children. According to Mock and Parker (1998), "In many sexually reproducing organisms, parents produce far more offspring than their resources can support [...] [leading] to acute competition." Therefore, any investment in illegitimate offspring on the part of the male is unfavorable to his legitimate offspring because he has a limited number of resources to give. A mother is better able to ensure non-genetic resources for her own offspring if hers are the only ones amongst whom the resources are allocated.

While Trivers' (1972) theory of parental investment appears to be extremely sound, there are many other variables to be considered when trying to create an accurate illustration of the human reproductive process. As pointed out by Buss and Schmitt (1993): "In human evolutionary history, both men and women have pursued short-term and long-term matings undercertain conditions where the reproductive benefits have outweighed the costs." Perhaps the most difficult task is to account for all of the different possible reproductive secnarios, especially when the variables of human emotion become involved--advances in paternity testing and fertility treatments will certainly lead to even more interesting observations on the subject. However, it seems that in general, most human mating behavior can be explained somewhat on an evolutionary level. By reconciling their different sexual ideals, male and female humans have successfully established the current process of human reproduction.

REFERENCES

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Gray, P. (2007). Genetic and Evolutionary Foundations of Behavior. In Psychology (Fifth ed., pp. 49-90). New York, NY: Worth Publishers.

Provost, M. P., Troje, N. F., & Quinsey, V. L. (2008, January). Short-term mating strategies and

attraction to masculinity in point-light walkers. Evolution and Human Behavior, 29(1), 65-69.

Abstract retrieved February 8, 2008, from PsycARTICLES database.

doi:10.1016/j.evolhumbehav.2007.07.007

Ridley, M. (1994, January 21). Unfaithful reproduction. New Statesman & Society, 30(2). Retrieved February 12, 2008, from General Reference Center Gold database: http://find.galegroup.com/itx/start.do?prodId=GRGM

Trivers, R.L. (1972). Parental investment and sexual selection. In B. Campbell (Ed.) Sexual selection and the descent of man. Chicago: Aldine.