Sorry I was unfaithful, my brain chemicals made me do it
THERE'S this evolutionary myth that's been round for years - that men are polygamous and biologically programmed to run around spreading their genes with as many people as possible in order to ensure the survival of the species. We women, on the other hand, are only looking for romance and a stable partner, and are genetically monogamous. Nice try, lads.
In reality, we females are just as sluttish as you men - and it's genetic. Biology and anthropology now explain how brain chemicals and hormones control everything from our lusting, our mating, our bonding and our capacity to stray. And here's news for the myth-makers - both men and women are programmed to cheat.
In their book The Myths of Monogamy, David Barash, Professor of Psychology and Judy Lipton, psychiatrist, explain it very simply. "Well, in a nutshell, the myth would have it that some animals mate for life, and that therefore it's natural for humans to do the same thing, but DNA fingerprinting has enabled scientists for the first time, to see that so called monogamous species - mostly birds such as ducks, geese and albatrosses - actually have affairs, and that anything between 10 per cent and 70 per cent of their offspring turn out to be fathered by males other then their partners.
"Add to this that mammals in the wild enjoy promiscuous sex lives and that 85 per cent of human societies are non-monogamous, and suddenly you have yourself wondering how the idea of one life-long partner ever got off the ground in the first place."
The authors concede that people might aspire to monogamy but, in reality, it's quite rare. But, to understand the chemistry of love, sex, bonding and straying we have to look at the chemical process. Let's start with looks. We are attracted to face symmetry, while features that remind us of our parents give us a chemical rush of phenylethylamine (PEA), the euphoric chemical which causes that head-over-heels feeling when you can't stop thinking about a person.
Oxytocin is the bonding chemical. It causes contractions in childbirth, orgasm and menstruation, but it is also responsible for affection, parent/child bonding, deep friendships, even loving your dog. We could not fall in love without this chemical, which fuels the selfless desire to nurture and be close to each other.
Lust, on the other hand, is caused by the hormones testosterone and oestrogen which prompt us to mate. That's when pheromones come in to play, chemicals that interpret by smell a mate's potential genetic make-up.
In 1995, a study in the university of Berne in Switzerland asked a group of women to smell some unwashed T-shirts worn by different men. What they found was that women consistently preferred the smell of men whose immune systems were different than their own, which acted to enhance the chances of survival of theiroffspring.
Psychologists have shown it takes between 90 seconds and four minutes to decide if you fancy someone, and it has little to do with what is said - it has more to do with body language and tone and speed of voice. During the attraction stage, you're being flooded with adrenaline, dopamine andserotonin.
The adrenaline causes palpitations and blood rushes - hence the flushed face or heart flutters. Serotonin causes mood fluctuations and is responsible for those thoughts that keep popping in to your mind.
You know that feeling of being insanely in love? It is, in reality, exactly that - insanity. Studies show that the reasons you constantly think about your new lover are akin to the mechanisms of Obsessive Compulsive DisorderSyndrome.
Blood samples from the newly-in-love show that serotonin levels were the same as those in patients suffering from Obsessive Compulsive Disorder. Newly smitten partners often idolise their partner, magnifying their virtues whileignoring their flaws.
After all this lusting and mutual attraction, the time for sex comes. Sex has many characteristics which are the very same as addictive behaviours. Sex is regulated by the brain's limbic system and is driven by the region known as the reward centre. The highs and lows of dopamine explain the one-night stand, the sexless marriage, high rates of infidelity and pornaddiction.
In humans, brain scans of people having orgasms resemble the brain scans of people having a heroin rush. Dopamine soars during sex and orgasm and then drops dramatically.
To the addictive personality, this is a problem. When dopamine is normal we display feelings of well-being and make healthy decisions. We are optimistic and feel good about ourselves.
When levels of dopamine are too high - which also happens when taking nicotine, cocaine or heroin - we become single-minded and demanding. This can be powerful and is vital for survival, driving us to eat, drink, take risks and not least, engage in sex.
And in today's modern culture we have ample opportunity to over-stimulate dopamine: alcohol, compulsive shopping, recreational drugs, and junk food. We don't even need to leave our computers to feed our addictions - high levels of dopamine are associated with gambling, fetishes, anxiety, and so on.
Nature tries to help us along after orgasm by zapping us with prolactin, which has many functions in the body but here it seems to act as a sexual satiation mechanism, bringing on that "roll over and snore" feeling . . . well in men anyway. Women get it too, but it takes a bit longer to set in.
The chemical androgen is also released after orgasm. In male rats that lessened the effects of testosterone and changed their behaviour. The rats lost their libidofor up to seven days. But, no matter how uninterested in sex the ratwas while going through itsandrogen phase, when a new female was introduced in the cage, up he popped and was at it again. This process can be repeated again and again until the poor rat nearly dies.
Now don't think the female rat just sat there not caring. When given a chance, she was just as eager to seduce a new mate, and it was only when oxitocyn was injected into key areas of herbrain that she stayed loyal to her first mate.
So the answer to keeping us all faithful would be large oxitocyn injections all round. The only snag is that the hormone only works on those who produce it themselves. Yet there are ways of stimulating our brains to produce oxitocyn - touch, stroking, massage and non-orgasmic sex.
All in all, though, we humans have morality and we have a conscience. We have free will. And the decision to cheat although compelled by our genes and our chemicals is, at the end of the day, exactly that: a decision.
Many believe having free will is what sets us apart from the animal kingdom. Religion tells us that that's what aligns us to God and that our purpose on Earth is to overcome these primal urges - so, we are a glorious dichotomy of deep genetic programming, which is very hard to override, and philosophical pondering and exercised control.
Just because something is natural doesn't make it good for us. Earthquakes and hurricanes are natural and not very much use to humans, so I'll leave you with the words of comedian Chris Rock: "It's true that both men and woman are as faithful as theiroptions."