When challenging the preferential status of marriage, I am often countered with “but marriage is natural!” No, it is not. Reading about the history of marriage in general and in the US in particular, it is clear that marriage is an institution created with specific civic purposes, which changed over time but were always there. In the US, it is steeped in the Christian tradition of monogamy, which the founding fathers imposed on the new nation.

Of course, this is avoiding the real question: Is coupling natural? I suspected that it is for reproduction and possibly for child-rearing but not for personal fulfillment seeking and happiness achievement. Certainly, the idea of a soul mate can’t be natural, I figured. Fortunately, there are people who have done the research for me. Elizabeth Pillsworth and Martie Haselton have written a commentary in response to a paper by Bella DePaulo and Wendy Morris. In their commentary, Pillsworth and Haselton summarize the evidence from evolutionary psychology. Their answer? Yes, coupling has evolved to facilitate reproduction and, to some extend, child rearing. Evidence from a variety of disciplines indicates “a species-typical pattern in which individuals generally seek long-term cooperative reproductive relationships.” Longer-term coupling also helps decrease the risks of pregnancy. And “the formation of pairbonds may be an adaptation for caring for offspring.” The desire to couple also seems to be universal and rather resistant to ideologies:

Men and women are more likely to form lasting, semi-exclusive pairs than to pursue a lifelong strategy of casual, fluid relationships.

However, before the Religious Wrong celebrates (willfully ignoring that they would have to accept evolution to accept this argument but that’s another story), let’s read on. It is important to distinguish between the evolutionary reasons for coupling – reproduction and child rearing – and the cultural overtones, especially those included in the more recent idea of a romantic partner. Pillsworth and Haselton stress this distinction:

Evolutionary approaches suggest that humans will possess a strong desire to form conjugal pairs, but nowhere in evolutionary theory do we see the prediction that one’s romantic partner will serve all social functions.

Matrimania is neither natural nor a direct consequence of the evolutionary grounding of coupling. This is because coupling serves specific evolutionary purposes: reproduction and caring for the offspring. So, someone can have excellent reproductive potential but might be a lousy partner (and sometimes reproductive ability and parenting doesn’t even co-exist in the same person, which has lead some species to split even those roles).

There is, therefore, nothing from an evolutionary perspective that would suggest that all relationship roles can be collapsed into a single partner. Each type of relationship serves its own unique set of purposes, guided by specialized adaptations.

Yet, modern marriage, and to a large extend intimate relationships, seem to presuppose this role collapse. We are not looking simply for a father or a mother for our children when we’re looking for a partner. No, that person has to be our best friend, be interested in almost everything we’re interested in, must be good to talk to, fun to be with, laugh at the same points in the movie, oh, and be good looking, of course, terrific in bed etc etc etc. This modern ideal, then, is almost unnatural – it goes against the evolutionary adaptation mechanisms that helped specialize certain roles.

Aside from the role collapse, Pillsworth and Haselton also point out that “the fact that humans have adaptations for coupling does not imply the moral superiority of coupled individuals.” A couple who can reproduce and rear children is necessary for the survival of the species. They don’t have to be happy. In fact, they really only need to be alive long enough to raise the offspring, who tend to be self-sufficient around 15 years of age (well, used to at least…). The other, very important caveat, is that

the psychological adaptations underlying coupling evolved in an environment that differed in many ways from the one in which we live now.

In other words, just because something was necessary thousands of years ago on the savana doesn’t mean that we can’t move beyond it nowadays. Thus, coupling might make just as much (or little) sense as the gendered-division of labor. In today’s world, men and women can pretty much do most jobs equally well. So, we should be able to seek fulfillment without the traditionally prescribed panacea: marriage.

Finally, Pillsworth and Haselton examine the bias against singles, which they suggests “exists because relationship status conveys information with reproductive relevance.” If someone has always been single, this might be an indicator that they are “exceptionally low mate material.” However, just like coupling in general, this evolved reason may no longer be very relevant in modern society. Remaining single can be a reasonable choice and, thus, does not reflect at all on one’s reproductive ability. The information conveyed by the single status, which was crucial to our ancestors, has lost its value in today’s society.

Why, then, does the argument that marriage is naturally meeting our needs so pervasive? Pillsworth and Haselton offer this observation:

Coupling is so pervasive, and thinking differently about singles so natural, that singlism has virtually escaped notice until now.

Just like racism, sexism, and heterosexism might have developed around some biases in our evolutionary past, singlism exists because we are not counteracting what we, as a species, have learned. This is especially the case in the US:

In American society, we appear to have merged several social roles into a single relationship. […] In most cultures around the globe, your spouse is not your best friend, or even your primary social partner.

It seems that we are counteracting some evolved forces – those that gave specialized purposes to other relationships – by focusing our attention on only one force: coupling. The idea that a partner is a soul mate is not only historically very recent but also might be an evolutionary counter-productive social adaptation. By putting all our relationship-eggs into one basket – marriage, whether the legal kind or the look-alikes – we are ignoring lessons from evolutionary psychology.

(Hat tip to Bella DePaulo for pointing me to this commentary.)