Friday, June 10, 2011

Love in the Jungle, Part One

I've recently read two excellent books that covered similar territory, namely, the social and moral rules that govern the behaviors of social animals. One of these books The Myth of Monogamy: Fidelity and Infidelity in Animals and People, by David P. Barash and Judith Eve Lipton focused entirely on the rules governing sex and fidelity, as the title makes clear. The other, The Moral Lives of Animals, by Dale Peterson, focuses on morality among social animals in a broader sense. I hope in this post to give the reader some incentive to read both of these excellent books, to illuminate some parallels, and perhaps to draw some of my own conclusions.

            Before we get started, I would like to bring something to the fore of the discussion. As I have covered many times on this blog, some people, particularly those in the social sciences, have an innate dread of any discussion that touches on the way nature, through natural selection, might have shaped any aspects of our cognitive life. As I have pointed out many times, this is both naive and foolish. It is naive because accepting that evolution shaped every aspect of our bodies, including the material of our brains, which the evidence absolutely overwhelmingly suggests it did, but thinking that it wouldn't have also shaped the way those brains work, simply doesn't make any sense. How entire disciplines exist that operate under the provably false notion that our brains are a tabula rasa, a blank slate, and still receive funding and adulation, is quite beyond me.

            But why? Why do so many sociologists, psychologists, anthropologists, feminists and others continue to labor under a long disproven assumption? While there are many in these fields that are coming around to a more realistic understanding of their subject, there are still many who refuse to acknowledge that biology or evolutionary theory could possibly have anything to say about the very creatures these processes created. The primary motivator here, it seems to me, is fear. The goal of many of the disciplines is to demonstrate that the problems in our society, violence, economic, racial and sexual inequality, are merely the result of historical accident, and thus, are easily reversible. Further, the greater fear is that if any of these problems can be shown to have any basis in nature whatsoever, then that will be used as justification for their existence. (This is not surprising, given our society's naive, and foolish, associations of nature=always good, man-made=always bad, but that is another post.)

            However, although there may be historical precedent for these fears, eugenics comes to mind, that doesn't give the truly interested and honest thinker any right to discard reality. If there are natural reasons why people are violent, dishonest, unfaithful, or distrustful of people who don't look like them we need to understand them, not ignore them. Only by taking the time to understand the roots of our problems can we even begin to hope to remedy them.

            So I will take the same position as the authors of both of these books. What they have discovered in their studies and research is that virtually every aspect of human nature can find an analogy in animal nature, especially among social animals. Among the bigger-brained creatures- elephants, hyenas and wolves, whales and dolphins, and of course, our cousins the primates- the resemblance is uncanny. They argue, as do I, that we should take this into consideration when we try to better ourselves and our society. What parts of our decision making are wired into us before we are even born? How much can we change these impulses? Which ones benefit us and which ones hinder us? And it is only by understanding the origins of these impulses that we can begin to talk rationally about altering them.

The Myth of Monogamy

           Barash and Lipton are an interesting pair to write a book whose thesis is that monogamy, as most people conceive of it, is almost unheard of in nature. First of all, they are married to one another (since '77). Secondly, they hail from two of the fields which I just mentioned as typically being resistant to the use of evolutionary theory applied to our mental lives, as he is a professor of psychology and she is a psychiatrist specializing in women's issues. But perhaps it is this unconventional starting point that makes their work so convincing.

           Barash and Lipton's goal is not to convince human beings to behave one way or another. Their purpose is to take a look at the phenomenon known as "monogamy" in nature and expose it for what it really is, which is nothing like what human beings think of when they are standing at a wedding altar promising to be "forever faithful." Their book actually involves very little field research of their own, but is instead an accumulation of findings by biologists studying different animal species all over the globe.

           Some terminology is necessary here. Barash and Lipton make a distinction between two types of "monogamy." They define "social monogamy" as a pair-bond between two animals who mate sexually and share some degree of responsibility for obtaining food, maintaining a territory or nest, and caring for offspring. The degree of this shared responsibility varies from species to species, and even within species, though it is almost always the female doing the bulk of the caring and providing and the male doing the protecting, those these roles are sometimes more equitable, and sometimes, though rarely, reversed. What they call "sexual monogamy" is much more recognizable to us when we use that term, and they only use it to refer to absolute and utter sexual fidelity on the part of both partners who are also in a socially monogamous situation.

           For many, many, years biologists and naturalists have surveyed the natural world and the creatures within it and come to believe that most animal species which were socially monogamous were also sexually so. However, the development in recent decades of cheap, reliable and rapid DNA testing is obliterating this notion. In other words, it's not just NBA players who are getting exposed by paternity tests. It's almost every creature out there. What is being discovered is that among virtually every species that appears socially monogamous, even the virtuous birds, building their nests together, regurgitating worms and insects for their brood, protecting the nest together, there is a little somethin'-somethin' going down on the side. 

            The term they use for this (last definition, I promise) is one of my new favorites, for the very dry way it captures something so naughty; extra-pair copulations, or EPCs. And what biological research is showing is that in virtually every species, among both males and females, there is some EPCing going on.

             Further, across the majority of species, including many, many birds and mammals, but also fish, reptiles and amphibians, the different reasons the two sexes seek EPCs are very similar (to members of the same sex in other species). This is due to two very simple biological facts. The first is the single fact that defines gender in the natural world; cheap sperm, expensive eggs. Males of virtually all species produce sperm constantly and by the millions. Females, in contrast, produce a limited number of eggs (relatively speaking, because this number can also be in the millions). This single fact forces females of virtually every species to be more selective in their reproductive dalliances than males. And this shapes everything. Among species that carry their young in an internal womb, such as mammals, females, by virtue of being irrevocably connected to their offspring for at least the duration of the pregnancy, the difference in reproductive strategy is even more pronounced. The second fact further reinforces the first; maternity is almost always known and guaranteed, paternity is not. This also has a massive impact on the differing reproductive strategies employed by the sexes as well, as we shall see.

          While it would be impossible to go over every example that the authors give, I can identify some recurring themes. An individual is successful, in evolutionary terms, when it succeeds in getting its genes into the next generation. It is especially successful when its offspring themselves have a high chance of survival and reproductive success, and so on. (This is an over-simplification, but it wil suffice for our purposes.) Now, because of the differences between the sexes, the most viable male strategy is often, though not always, to focus on the first part of this goal, and the female strategy is almost always to focus on the latter. These differences can be described as quantitative versus qualitative. An usefully analogy might be a game of darts, where the male strategy is to just grab fistfuls of darts and huck them at the board, hoping something sticks, where the female strategy is to take a few darts, steady and aim very carefully.

            And it is easy to see why. If a male can reproduce for no more cost than that of a few sperm, why wouldn't he? (Remember, this is evolution's logic, not a prescription for behavior among human beings.) It's not that male birds or frogs or mice are particularly inclined towards fatherhood, it is simply that those who do have the impulse to copulate more frequently are more likely to have the more offspring, who themselves will likely feel the same impulse. Over thousands and thousands of generations, every living member of the species would eventually be the descendant of one of these super-copulators.

             But it isn't always this simple. For males of socially monogamous species, there are other factors to consider. The first, of course, is which females is he scoring an EPC with? If she is unattached and willing, it is almost certainly "worth" the time and energy. But if she is attached, to whom? Someone bigger, stronger, fiercer or faster? Then it might actually not be worth it, unless it can be accomplished in absolute secrecy. And while he is off seeking EPCs, what is his mate up to? Is his eagerness leading to him getting simultaneously cuckolded? This leads males of all socially monogamous species to balance these factors when seeking EPCs; danger of physical retribution from the cuckolded male and getting cuckolded one's self versus the likelihood of an easy chance at reproduction.

             Of course, if males are scoring EPCs, they must be finding females willing to cheat on their socially monogamous mate. When would this be a viable reproductive strategy for females? Well, according to the research, time and time again, across species and among birds, mammals and others, females seemed willing to cheat if and only if they were presented with an opportunity to mate with a more desirable male. Over and over, it seems that females are willing to transgress when there is an opportunity to do so with a male who is of a higher social rank, which means he carries higher-quality genes. Females almost never had EPCs with males of lower social standing that their own socially monogamous mate. And most fascinatingly, females were more likely to transgress while in estrus, but again, only if a higher-quality male could be wooed.

            Why might this be? What do females stand to gain, from an evolutionary perspective? Well, the benefits for her male offspring are obvious. If her male offspring carry the genes for social dominance, they are more likely to be the males of the next generation who are scoring the most desirable females, and more of the EPCs. If her female offspring carry those genes, some may be beneficial to them, but they will also be beneficial to the original transgressor's male grandchildren.

            But just like with males, EPCs are a complicated business for females. At what risk do they transgress? Well, the primary risk is physical retribution from her social mate, since males of most species are bigger and more aggressive. According to the research cited by the authors, male physical retribution for female sexual transgression occurred widely across species. There is also the risk of abandonment. Since a female by default invests more in her offspring from the moment her valuable egg is fertilized, through pregnancy or egg-sitting, right up on to breast feeding, it is much less desirable, from an evolutionary perspective, for her to abandon her offspring. But since all it has cost the male up to this point is a few sperm, he is much more likely to walk away if he has reason to believe that the offspring he is planning on investing time in might not be his own.

             These complications help explain why females were much more likely to risk an EPC during estrus and only with higher-quality males. It is not worth the risk of violence or abandonment to have an EPC with a male other than her social mate unless there was a high chance of conception and if the male carried genes that worth superior to her own mates. Otherwise, she is just causing herself unnecessary risk and trouble for little or no gain.

             Most of what has been said is regarding species that pair-bond, one male and one female. Of course, the rules are different for other species, who evolution has pushed in a different direction. Other than pair bonds, what other sexual arrangements have other species come to? One of the other most common arrangements is for one sex to engage in fierce competition for sexual access to the other, with the winners,  the "alphas," gaining almost exclusive sexual privilege. When this occurs, physical competition tends to drive up the body size of the competitive gender, so it is generally very easy to spot these species, because one sex is much larger than the other. In general, of course, the competitive sex ends up being the male, although there are a few exceptions among insects (and hyenas, although it is more complicated.)

              This "sexual dimorphism," where one sex is physically larger and more powerful than the other, is most pronounced among the "harem-keeping" species, such as lions and gorillas, where the males can be several times larger than the females. But it is also quite present in whales and elephants,  which don't rule over harems, but where sexual access is determined entirely by social status, which is obtained through victory in violent physical contest. But in either of these cases, it is female preference for socially and physically dominant males that drives the dynamic.

                I could go on for pages, but I would essentially be regurgitating the book, which isn't the point; I'd rather have you give the author's their due and read their work. But what does this mean for us? Remember, I have only been talking about animals, although primarily social animals like ourselves. But if you've read the first part of this post and haven't seen elements of human behavior in what I have described, I'd be shocked.

             What do we know about humans? Where do we fall in this spectrum? A first thought, for those of us living in the west in the 21st century might be, "Well, we're a pair-bonded species." Not exactly. Among many societies throughout history, other social/sexual arrangements have been the norm. The most common being, for many centuries, in many cultures, polygamy, where a man has multiple wives. There have also been some recorded instances of polygyny, where a woman has multiple husbands, but they are much rarer. If we take what we just stated about sexual dimorphism into account, this makes sense. Human males, are on average, several inches taller than females and several tens of pounds heavier. We are nowhere near the extreme of our harem-keeping gorilla cousins, where a male silverback can weigh two or three times what the females in his harem do, but neither are we physically identical in size, as are our famously egalitarian cousins, the bonobos.

            Now, let's be careful here. This is not intended as a justification of polygamy, nor of harem-keeping. But when we look back across the annals of history, and even at  the many polygamous cultures  that still exist, it is helpful to understand where this impulse comes from. Our society has decided, and I would agree, that the most peaceful and equitable social arrangement is for one male/ one female social pair-bonds. (Or two males, or two females, if that floats your boat, but that is a different topic.)

             But we all know that good intentions are not enough. Infidelity happens. We have all seen it, heard about it, felt its sting or even done it ourselves. We love to pat ourselves on the back for our technological achievements, sing the praises of our sophisticated culture, erect monuments to our own glory and put flags on the moon. So it is sometimes useful to take a close look at sparrows, because if we look with open eyes, we see ourselves.

              Fortunately, we do have a tool which is unavailable to sparrows or chimps. Culture. Yes, we can decide that we are better off if we find a mate and remain true to that person for life, or at least a good long while. We can learn these behaviors, we can teach them to our children. But it isn't like learning to eat or breath. When we do this, we are making a decision that goes against some parts of our nature.

              Know thine enemy.

          (This post got a bit long. So the discussion of Peterson's book will be in the following post, along with a conclusion.)

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