Sexual orientation and love vs sex

I was reading a paper called "What does Sexual Orientation Orient?" by Lisa Diamond, and it blew my mind. In it, Diamond presents a model of romantic love and sexual desire. She argues that the two are functionally independent, and that people can have one without the other.

Love and sex, after all, evolved for different reasons at different times. Sexual desire primarily evolved for the purpose of reproduction (not to say that sexual behavior didn't further evolve for other purposes). Romantic love, on the other hand, evolved so that parents stay together long enough to care for their offspring. There are two separate mechanisms, so perhaps they don't always come together.

And in fact they don't always come together. People generally accept the idea of sexual desire without romantic love, but it goes the other way too. A high number of people report experiencing infatuation without the sexual attraction. But of course, many other people do experience the two together. This is because, most of the time, sexual desire for a person is soon followed by romantic feelings for the person. Diamond argues that this link can go in the other direction too. In other words, romantic feelings can lead to sexual desire. Interestingly, the link between romantic love and sexual desire appears much stronger among women than among men.

There are, by the way, two stages of love. Diamond states this not as a new idea, but as one which comes from the scientific literature (not that I had ever heard of it before). The first stage, known as passionate love, or infatuation, is characterized by a desire to be close to the person, a fascination with their appearance and behavior, and so forth. The second stage, known as companionate love is characterized by "feelings of calm, security, mutual comfort seeking, and deep affection." Note that both stages of love can possibly without sexual desire.

Diamond suggested one rationale for these two stages, which I thought rather enlightening. Companionate love requires sustained proximity between the two people. Passionate love motivates people to be close together, allowing for the development of companionate love.

Diamond goes on to explain a surprising evolutionary path for love (Warning: evolutionary psychology ahead!). Before the evolution of adult romantic love, there was the love between the infant and the caregiver. Rather than creating a whole new mechanism of love from scratch, evolution took the mechanism for infant-caregiver love and made what is now romantic love between adults. You might compare it to how feathers originally evolved as insulation, but were later adapted for flight.

I'm not sure I buy this evolutionary mechanism for love. With evolutionary psychology, it can be hard to tell the difference between a well-supported theory and a just-so story. It's especially difficult for me, because Diamond talks about about all this oxytocin and stuff and I don't understand any of it. It seems to be well-supported, so I will accept it for the moment.

Diamond goes on to say that infant-caregiver love does not have an orientation! Infants don't prefer one gender over the other, that would be maladaptive. She uses this fact to argue that romantic love is not intrinsically oriented towards either gender either. And so Diamond's model comes together. Heterosexual people can fall in love with the same gender, and homosexual people can fall in love with the opposite gender. And since romantic love can lead to sexual desire (especially among women), people can end up having sexual desire for a gender which is contrary to their orientation. This goes a long way to explaining why heterosexuals sometimes unexpectedly fall in love with a single specific person of the same gender, and why homosexuals sometimes unexpectedly fall in love with a single specific person of the opposite gender.

However, I must voice a small disagreement I have with Lisa Diamond's model. If romantic love had no intrinsic orientation towards either gender, then why do the majority of people fall in love only with the opposite gender? Diamond argues that this is because of other influences, such as cultural influences. For example, people tend to hang out more with people of the opposite gender, so they fall in love with the opposite gender more often. But... I'm not sure that's really true in all cultures.

I also find the evidence for this assertion to be rather weak. Even if I accept that romantic love evolved from infant-caregiver love, that doesn't mean that they are identical in every respect. Perhaps romantic love later evolved to be oriented towards one gender or the other. Outside of the evolutionary argument, Diamond admits that there are only a few pieces of direct evidence for her claim. Her main piece of direct evidence revolves around prairie voles, and simply isn't convincing to me.

It seems to me more reasonable to say that there are two orientations: sexual orientation and romantic orientation. For most people, these two orientations are the same. But occasionally they differ, and who knows, biromantics might be more common than bisexuals, or maybe everyone is weakly biromantic. This adds another intriguing layer of complexity to the idea of sexual orientation.

Also see "Emerging Perspectives on Distinctions Between Romantic Love and Sexual Desire", a shorter article with the same thrust. Or see Sexual fluidity, a whole book by Lisa Diamond.