My Girlfriend's Boyfriend?

Subscribers of the paleo-lifestyle use the "we are adapted to caveman life, therefore we should live more like cavemen" argument to advocate more than just eating like cavemen; they think that our sexual habits should follow "caveman sexuality" as well. As fun as caveman sex sounds, Zuk again uses an educated evolutionary argument to show that there has never been one single manifestation of human sexuality. Following the logic that people have evolved to eat different things at different times (yes, in the time since the paleolithic), Zuk argues that humans have evolved to enjoy a spectrum of sexuality, ranging from stoic monogamy to swinging polygamy. Generally, the form of sexuality present in a particular culture is dependent on the environmental factors that influence how reproductive success is maximized.

The paleo-lifestyle argues that cavemen were polygamous and that our modern divorce rate and marital conflict comes from our instance that monogamy is the only option. Paleo-lifers argue that in mammoth-hunting and loin-cloth-wearing times, many people would act as parents to many offspring whether they were the actual biological parents or not. Babies, they argue, are raised by a community, not by a pair, and our insistence on monogamy also disrupts healthy infant development. This makes sense: we could have only evolved one way, and must still be that way, right?

If you've been following this blog, you'd know that that argument reeks of partially digested mammoth, and Zuk carefully demonstrates why. She describes anthropological studies on human sexuality in various cultures and shows that different human societies, living at the same time--but in different places--have different ways of doing things, so to speak. For example, children of the polygamous Gusii people of Kenya are "better adjusted, more empathetic, and more independent if they had strong attachments to at least one other person besides a parents while they were growing up". Tertiary helpers  might help children learn skills their parents may not know very well, and can help watch children if the parents need to do some other task. 

However, in the partially polygamous Dogon society of Mali, polygamy is associated with decreased survival and health of the children of second wives. In this context, the children of a man's first wife are prioritized over the children of second wives, likely due to increased resource competition. In this society, children of monogamous parents are better off than many of the children of polygamous parents. 

So it seems that in some environments polygamy is best, while in others monogamy confers the highest fitness. (I do acknowledge that both cultures I described have some degree of polygamy). The point is that there is no single "best" form of human sexuality. Thousands of years of evolution and adaption to different environments has given rise to the complex and seemingly contradictory face of human sexuality. Is the high divorce rate really a problem? Or are we living in a world of serial monogamy? What does our modern conception of sex have to do with horny cavemen? Well, one thing, to be sure: be it during the paleolithic or the anthropocene, when the gears of human sexuality get crankin', who doesn't want to don a loin cloth, run through the wild, and let loose the most primal of all yells?