My ex-boyfriend and his new girlfriend were coming to Dublin for a few days.

“You can stay with me”, I offered, and since they were trying to travel as much of the world as they could, for as little as possible, they accepted.
“Will that be weird for you?” my friend Sarah wanted to know. I didn’t think it would be, and as it turned out I was right. But according to the tenets of sociobiology and evolutionary psychology, my lack of possessiveness was unnatural, perhaps even pathological.
Sociobiology and evolutionary psychology both apply the idea of evolution to human behaviour and both can be traced back to the publication of EO Wilson’s book Sociobiology in 1975. After Wilson’s next book On Human Nature was released in 1978, theorists began to investigate the idea that evolution had shaped our sex lives.
While they are not exactly the same, sociobiological and evolutionary psychology theories of heterosexual behaviour and relationships are pretty similar. The standard explanation is this: because of the amount of time, energy and commitment it takes to complete a pregnancy and raise a child, women are much choosier than men about their sexual partners. Women want men to be good providers and need to be convinced or seduced into thinking that sex with Man A is a better option than sex with Man B or no sex at all. Men, on the other hand, are apparently programmed to spread their seed as far and as wide as possible, but prefer attractive women to ensure that these multiple potential children have the best genetic start in life.
These theories tell us that men and women approach sex in divergent ways – women want stable relationships, men want multiple partners. Because we have opposing evolutionary approaches to sex, jealousy is inherent to human nature. Following this logic, women supposedly get jealous because we fear a rival will take away our partner’s material support. Men suffer from jealousy too. Since all men are theoretically trying to impregnate as many women as possible, fathers want to know that the child they are supporting is actually their own. Sociobiology and evolutionary psychology posit that these feelings are hardwired into us whether or not we have, or want to have, children with our current sexual partner.
The interesting thing about sociobiological and evolutionary psychology theories of sex and jealousy is that they seem to make sense, but only if you discount reams and reams of life experiences that don’t accord with them. Yes, men who have money generally do better with the ladies than men who don’t, but struggling musicians, average industrial wage slaves and lads on the dole still manage to get laid, and frequently too.
If women prefer rich men it is unlikely to be because of evolutionary reasons but because of social ones. On average, women still earn less than men and raising children is an expensive business. Despite this supposed need for good providers, any Saturday night out in most of the country’s clubs and pubs will show you that plenty of women are not particularly fussy about who they have sex with at all. The same can be said for men – any girl can pull, not only pretty ones. If only the rich or the beautiful were acceptable sexual partners, we wouldn’t be edging towards a global population of nearly seven billion.
Sociobiology and evolutionary psychology are popular in magazines and newspapers because anything that purports to explain sexual behaviour is deemed newsworthy. But for some strange reason we find it easier to accept that people behave in certain ways because of evolutionary reasons rather than social ones. Perhaps this is because evolution is beyond our control; if behaviour is formed by society then changing behaviour by remaking society is our responsibility – and frankly, who has the time for that?
So whether or not we approve of sexual infidelity, we accept the explanation that men cheat on women because they have an evolutionary need to sow their seed and women cheat on men because we are trying to get the best deal, either genetic or material, for our children. But actually, sociobiology and evolutionary psychology theories of human sexuality are much disputed and are regarded as deterministic, ethnocentric and universalising. What’s more, proving them according to acceptable and objective scientific standards is very difficult, if not impossible.
There is a much simpler explanation for modern human sexual behaviour, say psychologist Christopher Ryan and psychiatrist Cacilda Jethá. After years of collecting evidence from physiology, anthropology, archaeology and primate biology, Ryan and Jethá published their findings in 2010. Their book, Sex at Dawn: The Prehistoric Origins of Modern Sexuality makes an interesting and controversial claim – monogamy is unnatural, an evolutionary blip that arose out of the advent of agriculture. If you’ve ever had your heart broken, been through a divorce or felt the poignant sting of jealousy, well, the farmers are to blame.
Ryan and Jethá believe that agriculture introduced the notion of property into sexuality. When people lived in nomadic groups, personal property wasn’t important. Children were raised communally and although couples may have formed long-lasting loving relationships, sexual fidelity wasn’t part of the deal. Once people started settling in a particular spot to farm, humans began to acquire property and men became more concerned about paternity as they wanted to leave whatever wealth or land they had accumulated to their own children.
Until the advent of DNA testing, there was only one way for a man to ensure that his partner’s children were also his – by making sure she didn’t have sex with anyone else. Controlling female sexuality and fertility gave rise to all manner of charming things – the chastity belt, female genital mutilation, the chador and of course the demonisation of sexually active women as promiscuous sluts.
In the end I suppose it doesn’t matter if jealousy is evolutionary or an unforeseen and unfortunate consequence of agriculture, according to these theories at least, it comes down to the same thing – men get jealous because they don’t want to support another man’s child and women get jealous because we don’t want our children to go without. When I thought about that I realised that perhaps that was the very reason I wasn’t jealous – I’ve no children and he has no money, so we’re quits.
Theories aside, there was another more pertinent reason why I should have been jealous – he’d dumped me, and for her too! Granted we were involved in a somewhat ridiculous long-distance relationship and had agreed that, given the circumstances, monogamy was not an achievable goal, but still! At the time I was pretty annoyed and upset, but also rather relieved because the chances of us being able to live in the same country were almost close to zero. Besides which, since we had been friends and lovers on and off for over ten years, moving back into a friendship phase of the cycle didn’t seem like a huge loss.
I wish I could say that my lack of jealousy was because I am above these petty emotions, but that wouldn’t be true. Evolution may have given me breasts and fleshy buttocks and all manner of physical characteristics supposed to appeal to men, but it didn’t give me legs quick enough to outrun the green-eyed monster – more’s the pity!