Review
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Title: Out of Eden: The Surprising Consequences of Polygamy
Author: David P. Barash
Publisher: Oxford University Press
Genre: Popular Science (Biology)
Year Published: 2016
Number of Pages: 211 + Index
Binding: Hardcover, also Kindle
ISBN10: n/a
ISBN13: 978-0-19-027550-1
Price: $29.95
Reviewed by Christian N.K. Anderson for the Association for Mormon Letters
This book does a spectacular job of summarizing the broad and often-confusing field of the evolution of human sexuality. By deftly quoting poets and primatologists with equal force and frequency, Barash demonstrates conclusively that everything we know about evolutionary biology suggests that Homo sapiens are naturally polygamous–not monogamous, but not promiscuously adventurous either. Like ~85% of primate species, males desire long-term sexual relationships with multiple females (polygyny), and vice versa, though polyandry is necessarily covert due to male sexual jealousy–which is also an evolutionary adaptation to the differential costs of a cheating spouse.
I should clarify at the outset that Barash is writing about biological polygamy (i.e., the predilection for a long-term sexual relationship with multiple partners), not the socio-religious phenomenon in LDS history and fundamentalist groups. This definition may seem like “sleight-of-hand” on the part of the author, since from a westernized human perspective it sounds like he’s talking mostly about cheating husbands and wives. However, it is biologically correct; in the context of other cultures and other species it needs to be generalized, and—I think—it is a useful starting point for thinking about the “natural inclinations” that society and culture need to work with. He bookends the work with a particularly scathing (and relevant) critique of the harmful sexual scripts that so many get in monogamous societies: that polygamous desires before or after marriage are indications of severe moral failings rather than an indication of a healthy mammalian psyche.
SUMMARY
He goes about demonstrating his main thesis in a Popperian way: he proposes that humans are biologically polygamous, then shows how none of the ways you should be able to disprove this succeed in doing so. In polygynous species, males are (1) physically larger, (2) more aggressive, (3) mature later, (4) are related to other polygynous species, and (5) remain fertile longer than females. This is true of human males in every case. While he acknowledges that most males for most of human history have been monogamous, he dismisses this as due to mathematical constraints rather than preference. Furthermore, these constraints have been superseded often enough to leave their mark: 708 of 849 indigenous societies were “preferentially polygynous” before Western contact, and even within Western monogamies the genetic diversity of the Y-chromosome is much lower than the mitochondria, implying a significantly larger number of ancestral mothers than fathers.
He goes on to discuss how this polygamous past has tremendous explanatory power: cross-culturally and through time, men are 10-20 times more likely to commit a violent crime than women within any culture (even though a contemporary Honduranian woman is more likely to commit murder than an Icelandic man as the murder rate varies more than 100-fold between the two countries) because primitive men competed for mates and those echoes are still with us. It explains why men ejaculate more with a novel partner, why the number of wives scales with husband’s resource control, why women rarely marry down but men routinely do, why wealthy and powerful men have more sons than daughters, why human ovulation is concealed, why there is no society in the world where men do more fathering than women do mothering, the universal preoccupation with paternity, why bride prices are vastly more common than dowries, why children of junior wives have lower survival rates than senior wives, and so on.
He also gives the other side of the story an entire chapter: humans also have a very strong desire for long-term stable relationships, and monogamy confers some very substantial advantages to people who are able to swing it: stronger parental investment, a degree of social equality that limits the number of violent unmarried young men, and the hormonal and neurological rewards of life-long pair-bonding. These two contradictory impulses lead to a great deal of conflict, and as many as 1 in 9 marriages where the father is raising a child that is not his.
He then gives some very interesting speculation about why the label “genius” is so much more willingly bestowed on men than women: because males from peacocks to moose are evolutionarily rewarded for showing off their accomplishments. His section on homosexuality is regrettably weak, but followed by some particularly fascinating discussion (drawing heavily on Hector Garcia’s Alpha God) on how gods generally, and the Abrahamic God in particular, bear all the hallmarks of a harem master.
WRITING STYLE
Scientific writing is difficult because usually the authors are trying to objectively evaluate their own private speculations (they call them hypotheses) despite being the single person in the whole world most emotionally (and often financially) involved in these speculations. Popular scientific writing faces the double difficulty of doing all that while simultaneously being entertaining. In the tension between precision, clarity, objectivity, and humor, trade-offs inevitably have to be made—and Barash does about as good a job as it is possible to do in his provocative 38th book.
First, Barash is clearly enthusiastic about the subject and lets it show throughout; he mostly avoids stepping on emotional landmines by repeatedly reminding us this is “science, not advocacy”; and while this list of “just the facts, ma’am” might be disheartening to many, he reminds us that “’biology is [not] destiny’ but quite the opposite”. He communicates his key points by saying them several times in different ways, gradually adding technical jargon, an effective way to bring the audience up to speed with the field without overwhelming them. And while he doesn’t always succeed in clearly labelling his own private speculations as such, he usually does, and anyone paying attention to the footnotes can easily see where he speaks for the field and where he doesn’t.
Some choices are clearly made for entertainment value. For example, the first non-human mating system he discusses at length is that of the elephant seals, and it’s hard to think this decision wasn’t based at least partially on the sophomoric vocabulary deployed by the marine biologists of central California. Some infant male seals will suckle from a second female if she loses her pup, and thereby gain considerably more fat reserves by the time the year’s pups are abruptly abandoned by the adults at the age of ~6 months; these “double mother suckers” thus become “super weaners”. However, such choices and his bantering tone serve the text well to keep readers engaged, giving the impression that we’re listening to friend go off at the bar, rather than taking notes in a dimly-lit lecture hall.
BOTTOM LINE
Although I am a published evolutionary biologist, this book was crammed full of fascinating information that was new to me, and was consistently written with enough sparkle that I didn’t mind the repetition. While the book doesn’t discuss Mormonism directly except in passing (Joseph Smith as one in a long list of examples of religious leaders who used their social power for expanded sexual opportunities, the FLDS “lost boys” as an example of the social harms of polygamy, and 1800s Utah as an example of the correlation between wealth and the number of wives), it does provide a fascinating and novel perspective. Reading about the “alpha male God” changed the way I thought about Elder Christofferson’s conference talk where he asserted that the “role of father is of divine origin”. I may never think the same way about testimony meeting after learning that testimony comes from the same root as testis, and can be seen as a ritualized submission to the ultimate Harem Master. And I strongly agree with his ultimate message, which can be translated into Mormon-ese as: The natural man is an enemy to God, but “we are almost certainly less constrained by our biology than any other species” and are therefore free according to the flesh to act for ourselves. In addition to the inherent fascination of the subject, having a nuanced and accurate view of what these natural inclinations are gives us a better chance to successfully combat them.