Title: The Myth of Monogamy: Fidelity and Infidelity in Animals and People
Author: David P. Barash and Judith Eve Lipton
Publisher: W.H. Freeman and Co.
Examines biology and behavior of both people and animals
Reasonably restrained in drawing conclusions from evidence
Explores human and animal behavior
Explores human and animal physiology
Argues that monogamy is not necessarily "natural" for humans
Both have a lot of validity, but it is an interesting fact of life that many who ostensibly hold to the first view in theory actually practice the latter. The fact that monogamy is honored more in words than in deeds is a starting point for a recent book by David Barash, a University of Washington zoologist and professor of psychology, and Judith Lipton, a Seattle psychiatrist. These two researchers explore the nature of human mating strategies, particularly in the context of how other species seek and hold on to mates. According to the two authors, behavioral and biological evidence demonstrates very clearly that the inclination towards multiple mates is natural whereas monogamy is not.
They make it clear in the very beginning, however, that this is an entirely separate issue from whether or not monogamy is not possible or even desirable a fact lost on some who have read the book. Rather, the book explores the nature of that behavioral and biological evidence and then what that means for us.
As far as evidence from animal behavior goes, the DNA fingerprinting technology used in courtrooms is now being used by biologists to trace parenthood in animals resulting in some startling discoveries. Even among species previously believed to be monogamous, cheating on mates is the rule for both sexes. For example, in birds which were assumed to be monogamous, researchers have found that between 10% and 40% of all chicks were fathered by males who were not the mothers social mate.
Further research has shown that, contrary to popular assumptions, females are just as likely as males to engage in extra-pair mating. The methods used by the two sexes differ, but the basic reason is the same: evolution. Both males and females want to be sure that they produce the best possible offspring. But because of their different roles, they must adopt different strategies.
For the males, their role is providing sperm and sperm is cheap. A male can produce lots and lots with very little cost, so it makes sense to spread it around as much as possible. Males, then, essentially play the lottery: they try to mate as often as possible with as many females as possible in the hopes of producing as many offspring as possible. With luck, a few of them will do really well and continue the genetic line.
Females, on the other hand, cant play the lottery. Their role is in providing eggs, and eggs arent cheap. Females have to be more picky in choosing whom they will mate with and sometimes, they find a better male than the one with whom they are socially attached, thus leading to an extra-pair coupling. Sometimes, they also engage in such hanky-panky for the sake of extra food or protection.
With regards to biological evidence, it has long been widely known that humans possess certain characteritics typical of non-monogamous species. For example, monogamous species are also monomorphic, which means that both males and females are the same size. Polygamous species, however are dimorphic the male is larger than the female. This, obviously, is how humans are.
Assuming that the implications for humans are as strong as the authors contend, whats the point? Why did they go through all of this effort? It was not to validate adultery as some seem to think. Quite the opposite, actually they argue that their purpose was to better empower people in their efforts to remain monogamous.
The problem with monogamy is, as they explain over and over, that it is difficult. If it is not natural, and if our instinctual desires have a strong tendency to lead us astray, then we must devote more conscious effort to ensuring that we stick to what we have promised. Monogamy isnt like breathing, and the realization that we need to work at it may help keep us focused. On the other hand, if we pretend that it is natural, then it may be easier for us to go off on the wrong path before we realize it.
If you are interested in learning more about how monogamy and polygamy appear among both humans and animals, this is a pretty decent introduction. You will learn about biology, sociology, humand and animal behavior, and quite a lot more. It is designed with a general reading audience in mind, thus it doesnt get bogged down in technical or academic jargon.