The Science of Love:
* There are three phases to falling in love and different hormones are involved at each stage.
* Events occurring in the brain when we are in love have similarities with mental illness.
* When we are attracted to somebody, it could be because subconsciously we like their genes.
* Smell could be as important as looks when it comes to the fanciability factor. We like the look and smell of people who are most like our parents.
* Science can help determine whether a relationship will last.
Flushed cheeks, a racing heart beat and clammy hands are some of the outward signs of being in love. But inside the body there are definite chemical signs that cupid has fired his arrow.
When it comes to love it seems we are at the mercy of our biochemistry. One of the best known researchers in this area is Helen Fisher of Rutgers University in New Jersey. She has proposed that we fall in love in three stages. Each involving a different set of chemicals.
Three Stages of Falling in Love
Stage 1: Lust
Lust is driven by the sex hormones testosterone and oestrogen. Testosterone is not confined only to men. It has also been shown to play a major role in the sex drive of women. These hormones as Helen Fisher says "get you out looking for anything".
Stage 2: Attraction
This is the truly love-struck phase. When people fall in love they can think of nothing else. They might even lose their appetite and need less sleep, preferring to spend hours at a time daydreaming about their new lover.
In the attraction stage, a group of neuro-transmitters called 'monoamines' play an important role:
* Dopamine - Also activated by cocaine and nicotine.
* Norepinephrine - Otherwise known as adrenalin. Starts us sweating and gets the heart racing.
* Serotonin - One of love's most important chemicals and one that may actually send us temporarily insane.
Discover which type of partner you're attracted to by taking our face perception test.
Stage 3: Attachment
This is what takes over after the attraction stage, if a relationship is going to last. People couldn't possibly stay in the attraction stage forever, otherwise they'd never get any work done!
Attachment is a longer lasting commitment and is the bond that keeps couples together when they go on to have children. Important in this stage are two hormones released by the nervous system, which are thought to play a role in social attachments:
* Oxytocin - This is released by the hypothalamus gland during child birth and also helps the breast express milk. It helps cement the strong bond between mother and child. It is also released by both sexes during orgasm and it is thought that it promotes bonding when adults are intimate. The theory goes that the more sex a couple has, the deeper their bond becomes
* Vasopressin - Another important chemical in the long-term commitment stage. It is an important controller of the kidney and its role in long-term relationships was discovered when scientists looked at the prairie vole
Find out how the three stages can feel even stronger for teenagers in love, experiencing first love and first sex.
The frisky Prairie Vole: In prairie vole society, sex is the prelude to a long-term pair bonding of a male and female. Prairie voles indulge in far more sex than is strictly necessary for the purposes of reproduction.
It was thought that the two hormones, vasopressin and oxytocin, released after mating, could forge this bond. In an experiment, male prairie voles were given a drug that suppresses the effect of vasopressin. The bond with their partner deteriorated immediately as they lost their devotion and failed to protect their partner from new suitors.
Looking in their genes
When it comes to choosing a partner, are we at the mercy of our subconscious? Researchers studying the science of attraction draw on evolutionary theory to explain the way humans pick partners.
It is to our advantage to mate with somebody with the best possible genes. These will then be passed on to our children, ensuring that we have healthy kids, who will pass our own genes on for generations to come.
When we look at a potential mate, we are assessing whether we would like our children to have their genes. There are two ways of doing this that are currently being studied, pheromones and appearance.
Sniffing out Mr or Mrs Right
Human pheromones are a hot topic in research. They are odourless chemicals detected by an organ in the nose. Some scientists believe they could be the key to choosing a suitable lover.
Love rats Pheromones are already well understood in other mammals, especially rodents. These animals possess something called a 'vomeronasal organ' (or VNO) inside their noses. They use it to detect pheromones in the urine of other rats and use this extra sense to understand social relationships, identify the sex of fellow rats and find a mate.
In 1985, researchers at the University of Colorado found evidence that this organ also exists in most adult humans. So humans could also respond to pheromones.
Rats have different pheromones in their urine, depending on the make-up of their immune system. When rats choose a mate, they must avoid partners with an immune system too similar to their own, so that their babies can fight off a wider range of infections. As well as lurking in urine, pheromones are also found in sweat.
Love is...a sweaty T-shirt competition:
In 1995, Claus Wedekind of the University of Bern in Switzerland, asked a group of women to smell some unwashed T-shirts worn by different men. What he discovered was that women consistently preferred the smell of men whose immune systems were different from their own. This parallels what happens with rodents, who check-out how resistant their partners are to disease by sniffing their pheromones. So it seems we are also at the mercy of our lover's pheromones, just like rats.
At the University of Chicago, Dr Martha McClintock has shown in her own sweaty T-shirt study that what women want most is a man who smells similar to her father. Scientists suggest that a woman being attracted to her father's genes makes sense. A man with these genes would be similar enough that her offspring would get a tried and tested immune system. On the other hand, he would be different enough to ensure a wide range of genes for immunity. There seems to be a drive to reach a balance between reckless out-breeding and dangerous inbreeding.
What Makes You Fancy Someone?
Appearance could be another indicator of the quality of a person's genes. Research suggests that there are certain things we all look for - even if we don't know it.
It is thought that asymmetrical features are a sign of underlying genetic problems. Numerous studies in humans have shown that men in particular go for women with symmetrical faces.
The preference in women for symmetry is not quite so pronounced. Women are also looking for a man's ability to offer food and protection. This might not be indicated in their genes, but in their rank and status, for example.
The hour-glass figure
Studies have shown that men prefer women with a waist to hip ratio of 0.7. You can calculate your own using this formula:
Waist Measurement ÷ Hip Measurement = Ratio.
This seems to apply whatever the woman's overall weight. A group of researchers even compared this ratio with the average ratio of Miss America winners over the years. It was exactly the same. This ratio would seem to make sense as an indicator of a woman's reproductive health. When women age their waist tends to become less pronounced as they put on fat around the stomach. This coincides with them becoming less fertile.
Learn to Love yourself
Have you noticed how many married couples look quite similar? Studies have shown that more than anything we prefer somebody who looks just like we do. From a batch of individual photographs people can spot who are the couples with unnerving reliability.
Try our match-making quiz and give it a go!
Research has uncovered that there is a correlation in couples between their:
* Lung volumes
* Middle finger lengths
* Ear lobe lengths
* Overall ear size
* Neck and wrist circumferences
* Metabolic rates
Mummy's boys and Daddy's girls?
The latest studies indicate that what people really, really want is a mate that looks like their parents. Women are after a man who is like their father and men want to be able to see their own mother in the woman of their dreams.
At the University of St Andrews in Scotland, cognitive psychologist David Perrett studies what makes faces attractive. He has developed a computerised morphing system that can endlessly adjust faces to suit his needs.
Students in his experiments are left to decide which face they fancy the most. Perrett has taken images of students' own faces and morphed them into the opposite sex. Of all the faces on offer, this seems to be the face that subject will always prefer. They can't recognize it as their own, they just know they like it.
Perrett suggests that we find our own faces attractive because they remind us of the faces we looked at constantly in our early childhood years - Mum and Dad. Even the pheromone studies are now showing a preference for our parents' characteristics.
Examine your ability to read faces and to find your perfect mate by taking our face perception test, developed by Professor David Perrett.
Will it last?
Unfortunately there's no way of telling for certain if a relationship will last. But there might be some clues in your partner's family!
In studies of behavioral genetics it has been shown that a person's tendency to divorce is written in their genes. When scientists studied identical twins, they found that whatever their degree of marriage success was, they shared it with their sibling. Men who went through multiple marriages were highly likely to have a twin brother who did the same.
The numbers game
Perhaps the best indication as to whether your love will last come from statistical studies. Researchers have come up with several predictors for success. This is based on how you met and when, how you resolve conflict and how similar you and your expectations are.