Once upon a time (all great love stories start this way), there was a beautiful prairie vole; the most beautiful prairie in all the research pens. Let’s call her Sally. Sally wanted love, the type that makes your tail curl up and sets off butterflies in your stomach, but none of the prairies in her pen had ‘it’. One day, a new prairie entered the pen, let’s call him Harry. Harry was everything that Sally had been looking for. The sex was unbelievable and they couldn’t keep their paws off each other in the first few days of meeting. Over the next few months, the raw, physical passion that they had felt upon meeting subsided, but it was replaced with a feeling of contentment, safety and love. Sally had found her soul mate.
In nature, few animals are capable of maintaining monogamous relationships. Unlike their close cousin, the montane vole, prairie voles, can mate for life and remain with their furry love until the very end. A research team led by Sue Carter explored this difference in vain hope of perhaps discovering some of the clues to long lasting love and relationship satisfaction. Little did they realise that what they’d find would be applicable not only to the voles, but all animals including humans.
Love is like snorting cocaine. It lights up our pleasure centres and makes us crave for more. It releases powerful “good feel” hormones and like cocaine, it can isolate us from other people, hobbies and things and keep us returning over and over to the same person. When Sally was ‘in love’, the “cuddle hormone” oxytocin was released. It’s this hormone that lowers anxiety, lets us trust people and steal babies from strangers. Merely being close to someone that you care about is enough to increase oxytocin levels. When the research team blocked female prairies’ oxytocin output, their relationships became fleeting like the montane voles. Upon injection of the hormone, however, bonding pairs were reformed and female prairies would bitch slap any hoe-bag prairies that tried to steal their men.
Male brains don’t have as many receptors for oxytocin as females do, perhaps explaining why they, like dogs, need excessive pampering, rubbing and touching to stay happy. Instead, partner preference seems to be reinforced through the actions of another chemical, vasopressin. Stimulated by testosterone and orgasms, this hormone provides men with a laser-like focus that keeps them tracking their mate. It was the length of this chemical’s gene that Sue Carter found different among the prairie and montane voles. Free lovin’ montane voles have a shorter gene variant than the love crazy prairie voles but this difference in gene length isn’t just restricted to voles. Frivolous and promiscuous chimpanzees have a short variant of the gene whilst their bonobo brothers, which use oral sex and genital rubbing to resolve group tensions, have one that’s longer.
Ladies care more about the size of your man’s vasopressin gene than anything else. Even among humans, there are 17 different vasopressin lengths. The partners of males with short vasopressin genes are more likely to experience greater relationship dissatisfaction, problems in the bedroom, bad communication and marriages are twice as likely to end in divorce.
With divorce rates climbing up to 40% and over in Australia, one has to ask, what are we doing wrong? It would be easy just to run down to the chemist, get a vasopressin test and figure out the length of your date’s vasopressin gene, but surely that’s not the only factor here. What helps us find the person, or prairie vole, that’s right for us?
Let me tell you ‘bout the birds and the bees and the flowers and the trees
Birds do it, cats do it, and ferrets do it. Most mammals have a gland on the top of their nasal cavity, called the vomeronasal organ that detects sex pheromones and gets the little creatures excited and rowdy. These chemicals can alert potential mates as to when females are most fertile. A single Bombay moth releases enough pheromones to attract one billion males into her warm cocoon whilst silkworms can detect pheromones up to 11km away. So far, the existence of this organ in humans has been disputed but recent research suggests that pheromones may play a role in human attraction.
Ovulating lap dancers earn almost two times more than when they’re on their periods. During a 5 hour shift, dancers earn, on average, US$335 if they’re at their most fertile (during ovulation), US$185 when menstruating and US$260 when in between ovulation and menstruation. By contrast, dancers on the pill show no such discrepancies. Perhaps not as obvious as the silkworm that slithered through dirt for 11km to get some suga, but evidence is now coming in to suggest that pheromones and scents do play a role in the human world of love and attraction.
Our sweat and bodily secretions contain proteins of the immune system which bacteria on the surface of the skin break down to produce a perfume that is uniquely our own. This signature scent may play a role in helping us find ‘the one’. Late last year on his ABC program, Race Relations, John Safran panty sniffed for the sake of science. In his quest to determine whether he had a biologic predisposition towards Eurasian women, Safran collected ten dirty underwear samples and smelled each pair whilst blindfolded. The experiment showed that John Safran did indeed favour the Eurasian knickers over those that were Jewish.
The test performed by Safran was a modification of the Undergarment Test which showed that we tend to prefer the scents of others that are genetically dissimilar to ourselves. In terms of reproduction and evolution, this makes sense. If you do the dirty with someone who is more genetically different than yourself, your offspring will have a wider range of resistances since immune system genes are co-expressed. The kids get immune system genes from both the mother and the father. If you impregnate your sister, your children and future generations, are more likely to be mentally retarded and have genetic disorders.
The Human Leukocyte Antigen system (HLA) contains a large number of genes related to immunity and has been linked to relationship success and attraction. Cheating increases with the more HLA genes that you have in common with your partner. Couples with similar HLA genes are also more likely to have unsuccessful embryo transfers and in vitro fertilisations. It’s almost as though the body is trying to tell you that the person you’re with isn’t your prairie vole.
The Science behind homosexuality
Pheromones play a role in homosexuality as well as heterosexuality. Evidence for homosexuality has been provided through undergarment studies. It has been shown that homosexual males prefer the undergarment smells of other homosexuals and the smells of heterosexual women over heterosexual males. Lesbians also rather the smell of other lesbians, and heterosexual males over homosexual males. We seem to be more attracted to the smells of one sex over another and these attractions can increase the fitness of a population.
Evolutionists have been puzzled by the fact that homosexuality hasn’t yet been wiped out by natural selection since there is no way that the human race can propagate through same sex relationships. Two theories for this conundrum have been proposed.
If you look around you homosexuality is everywhere in the animal kingdom. Even on our beautiful Swan River, realise that one in every four black swan couples that you see is a homosexual one. In fact, homosexual black swan couples are infamous for stealing eggs or sometimes even being part of threesomes only to drive their female egg incubator away to raise the children themselves. Surprisingly, the children taken under wing by the homosexual couples have a great chance of surviving, perhaps revealing the importance of homosexual relationships to the survival of the fittest.
A strong correlation has also been recently found between homosexuality, bisexuality and increased fertility in female relatives. One study suggested that there may be a gene on the X chromosome which when expressed in women, allows for greater reproductive success but, when expressed in men, manifests itself in homosexuality. So, despite taking one male out of the mating field, the increased fecundity of the aunts, sisters and cousins of this homosexual male acts as a sort of reproductive compensation.
Am I with a prairie vole or a montane vole?
Our attraction and ability to form loving relationships to certain people makes sure that future generations are viable and healthy. In the case of Sally and Harry, the loving, monogamous bond between the voles ensured that their babies were brought into a caring and nurturing environment thus allowing for greater fitness. In humans, as in voles, children raised up by a single parent tend to have higher rates of mortality. In Australia, 83% of psychiatric hospitalisations and 75% of teens that commit suicide come from single parent backgrounds.
