The Myth of Monogamy: Fidelity and Infidelity in Animals and People (37 page)

The human species is preferentially and biologically polygynous, but also mostly monogamous and--when conditions are ripe--avidly adulterous ... all at once. There is no simple animal model that encompasses all of the "natural" human condition. Thus, in some species, males seek EPCs; in others, females do so. Which is the model for humans? Probably both.

Human beings use mate-guarding, frequent copulations,, and also a hefty dose of social prescription--religious injunctions, cultural conditioning, legal restraints, eunuchs, chastity belts, female circumcision, and so forth-- in efforts to impose their will (typically, the desires of powerful men) on everyone else's inclination. Rousseau speculated centuries ago that primitive human beings used to be happy, free, and socially independent of one another, but that most of our misfortune arose when the first people began identifying things--including sexual access to certain individuals--as their own. Maybe he was more right than most biologists have acknowledged, if many of the unpleasant aspects of male-male competition (notably, a penchant for violence) evolved because of the evolutionary payoff that comes with exclusive sexual access to one or more females. And with women inclined to accept, even seek, EPCs on occasion, conditions were ripe for the appearance of various increasingly competitive techniques whereby men tried to achieve sexual monopoly.

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At the same time, it is not simply the churlishness of men or the voluptuous transgressions of women that would have opened the floodgates of original sin. If women really had no sexual urges beyond their designated mate, there would be very few EPCs; similarly, if other men were not willing, even eager, gallivanters. Neither men nor women are the primordial purveyors of EPC sinfulness, if sin it be. It takes two to do the EPC tango. And human beings love to dance.

CHAPTER SEVEN

So What?

According to Saint Augustine, "The reason humans behave as they do is because they are not living in their true home." He meant God. Physical anthropologists mean that they are not living on the Pleistocene savanna! And students of animal mating systems could well mean that humans are not being permitted to live lives of polygyny or of monogamy plus EPCs.

But maybe our "true home" isn't such a nice place after all. Western tradition makes it abundantly clear where it stands on monogamy and on adultery. The Sixth Commandment could hardly be more specific: "Thou shalt not commit adultery." And for good measure, the Tenth proclaims: "Thou shalt not covet thy neighbor's wife." The Old Testament is especially harsh on such transgressors; in Leviticus (20:10) and Deuteronomy (22:22) we learn that an adulteress and her lover are to be stoned. The New Testament, by contrast, is more forgiving, as evidenced by Jesus pardoning the woman taken in adultery, enjoining "Let he who is without sin cast the first stone." (Interesting to note: There are no comparably harsh penalties for a man, so long as he is not adulterous with another man's wife. Unmarried women, it seems, are fair game!)

Sigmund Freud once argued that the universality of the incest taboo suggests that incest avoidance is probably not instinctive, because, paradoxically, if it were, we would not need the restriction. We only need to be prohibited, the argument goes, from doing what we might otherwise attempt; there are no taboos against biting off one's own ears, for example. The persistent and explicit prohibitions against adultery in Western (and many

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other) traditions similarly confirm the biological arguments presented in this book; namely, that strict monogamy is not automatic. It needs to be enforced and reinforced. Otherwise, adultery happens.

Christianity is especially exercised about adultery. Jesus even inveighed against committing it in "one's heart," consistent with the fact that Christianity has historically taken a dim view of sex generally. In fact, sex is considered so degrading throughout much of the Christian tradition that marriage was widely acknowledged to be inferior to chastity. Marriage, in this view, exists only as a way of preventing the greater sin of fornication (defined as sex among unmarried people). As St. Paul put it, "It is good for a man not to touch a woman, nevertheless to avoid fornication let each man have his own wife and let each woman have her husband" (I Corinthians 7:1-2). According to Bertrand Russell, in
Marriage and Morals,

the Christian view that all intercourse outside marriage is immoral was ... based upon the view that all sexual intercourse even within marriage is regrettable. A view of this sort which goes against biological facts can only be regarded by sane people as a morbid aberration.

According to John of Damascus, writing in the eighth century, Adam and Eve were created sexless; their sin in Eden led to the horrors of sexual reproduction. If only our earliest progenitors had obeyed God, we would be procreating less sinfully today (although it isn't at all clear how). "Matrimony is always a vice," claimed St. Jerome. "All that can be done is to excuse it and to sanctify it; therefore it was made a religious sacrament." Cleanliness is okay, but for many of the truly devout, celibacy was even closer to godliness. And sexual impurity was (and still is) dirty indeed. Christian monks up until the Renaissance complained bitterly of being visited in their sleep by succubi, female demons that gestured and beckoned lewdly to them, just as novitiate nuns were warned of the nocturnal visitations of their erotically enticing male counterparts, the incubi. For people who considered themselves married to Christ or to the Church, any sexual temptation--even if it involved nothing more than the occasional naughty dream or nocturnal ejaculation--was only slightly less sinful than outright fornication. The spirit may be willing, but the flesh can be adul-terously weak.

And, of course, if marriage is fundamentally flawed, acceptable largely as a way of making sex tolerable (so long as it is within the marriage), then how much worse is marriage with explicitly prohibited (extramarital) sex thrown in?

Notes

chapter
i Monogamy for Beginners

2
Marriage is the ultimate sanction: Or, at least, the ultimate interpersonal sin liable to be experienced by many people; adulterers outnumber murderers by a hefty margin.

3 On the other hand, there are cases: J.-G. Baer and L. Euzet. 1961. Classe de Monogenes. In
Traite de Zoologie, Tome
IV, ed. P.-P. Grasse. Paris: Masson et Cie.

5 In 1970, in what can truly be called: G.A. Parker. 1970. Sperm competition and its evolutionary consequences in the insect.
Biological Reviews
45:
525-567.

6
Here is an account of sperm competition [subsequent quote]: T. R; Birkhead and G. A. Parker. 1997. Sperm competition and mating systems. In
Behavioural Ecology: An Evolutionary Approach,
ed. J. R. Krebs and N. B. Davies. Oxford: Blackwell Science.

7 It required the next and most significant breakthrough: A. J. Jeffreys, V. Wilson, and S. L. Thein. 1985. Hypervariable "minisatellite" regions in human DNA.
Nature
314: 67-73.

8 It is presented not to provide [subsequent quote]: J. G. Ewen, D. P. Armstrong, and D. M. Lambert. 1999. Floater males gain reproductive success through extrapair fertilizations in the stitcKbird.
Animal Behaviour
58: 321-328.

10
There is also strong evidence: M. Morris. 1993. Telling tales explains the discrepancy in sexual partner reports.
Nature
365: 437-440.

10
Increasingly, biology journals: To avoid any misunderstanding, note that "tits" are to British ornithologists what chickadees are to biologists on this side of the Atlantic.

10
We have even had this oxymoronic report: D. E. Gladstone. 1979.
The American Naturalist
114: 545-547.

11
And this
before
having reached: W. B. Quay. 1985. Cloacal sperm in spring migrants: occurrence and interpretation.
Condor
87: 273-280.

11
Similarly, there is no guaranteed correlation: H. L. Gibbs, P. J Weatherhead, P. T. Boag, B. N. White, L. M. Tabak, and D. J. Hoysak. 1990. Realized reproductive success of polygynous red-winged blackbirds revealed by DNA markers.
Science
250: 1394-1397.

12
Even females of seemingly solitary species: P. S. Rodman and J. C. Mitani. 1987. Orangutans: sexual dimorphism in a solitary species. In
Primate Societies,
ed.

B. B. Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrangham, and T. T. Struhsaker. Chicago: University of Chicago Press; A. Schenk and K. M. Kovacs. 1995. Multiple mating between black bears revealed by DNA fingerprinting.
Animal Behaviour
50:1483-1490.

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THE MYTH OF MONOGAMY

12 More than 65 percent: R. A. Mulder, P. O. Dunn, A. Cockburn, K. A. Lazenby-Cohen, and M. J. Howell. 1994. Helpers liberate female fairy-wrens from constraints on extra-pair mate choice.
Proceedings of the Royal Society of London, Series B
225: 223-229.

12 Warblers and tree swallows: P. O. Dunn and R. J. Robertson. 1993. Extra-pair paternity in polygynous tree swallows.
Animal Behaviour
45: 231-239; K. Schulze-Hagen, I. Swatschek, A. Dyrcz, and M. Wink. 1993. Multiple Vaterschaften in Bruten des Seggenrohrsangers
Acrocephalus paludicola:
erste Ergebnisse des DNA-Fingerprintings.
Journal of Ornithology
134: 145-154.

12 Even prior to DNA fingerprinting: J. H. Edwards. 1957. A critical examination of the reputed primary influence of ABO phenotype on fertility and sex ratio.
British Journal of Preventive and Social Medicine
11: 79-89.

12 In response to surveys: E. O. Laumann, J. H. Gagnon, R. T. Michael, and

S. Michaels. 1994.
The Social Organization of Sexuality.
Chicago: University of Chicago Press.

13 The numbers for women are a bit lower: A. C. Kinsey, W. B. Pomeroy, C. E. Martin, and P. H. Gebhard. 1953.
Sexual Behavior in the Human Female.
Philadelphia: W. B. Saunders.

14 So polyandry, which means "many males": Etymological note: The word
polygamy
is often used incorrectly when
polygyny
is more appropriate.
Polygamy
literally means "many gametes" and is more precisely either polygyny or polyandry. People who speak of Mormon polygamy, for example, or polygamy as described in the Bible or as practiced in current Islamic and some African societies really mean polygyny, or harem-keeping.

chapter 2
Undermining the Myth: Males

17 At the same time, females: G. C. Williams. 1966.
Natural Selection and Adaptation.
Princeton, NJ: Princeton University Press.

17 An important conceptual breakthrough: R. L. Trivers. 1972. Parental investment and sexual selection. In
Sexual Selection and the Descent of Man, 1871-1971,
ed. B. Campbell. Chicago: Aldine; see also T. H. Clutton-Brock and A. C. J. Vincent. 1991. Sexual selection and the potential reproductive rates of males and females.
Nature
351: 58-60.

18 Under the pressure of sperm competition: G. A. Parker. 1982. Why are there so many tiny sperm? Sperm competition and the maintenance of two sexes.
Journal of Theoretical Biology 96:
281-294.

20 The function of these giant
Drosophila
sperm: S. Pitnick, G. S. Spicer, and T. A. Markow. 1995. How long is a giant sperm?
Nature
375: 109.

21 As to human beings [subsequent quote]: I. Schapera. 1940.
Married Life in an African Tribe.
London: Faber & Faber.