Love has inspired painters, songwriters and artists for centuries. Singers have cried that love will tear us apart and that love will lead us back together, that love can be tainted, and that the look of love is something to be desired. Some cultures have more than 10 words for love. But now scientists are starting to get interested in this fundamental human emotion, and this week on Mr Science, we will start a series of shows looking into this crazy little thing called Love.
The scientific understanding of love is still in its early stages, however when it comes to those warm tingly feelings inside us, it seems that our biochemistry is to blame. Right from the moment we are born, chemicals in our brain effect how much we bond with those around us. The love of a mother for a child is perhaps the most fundamental of loves, and scientists are now starting to understand that this love is cemented by a hormone called oxytocin. Late in pregnancy, the number of oxytocin receptors in the brain increases because of heightened levels of oestrogen. During childbirth, the hypothalamus gland releases high levels of oxytocin that then bonds to the many receptors, thus making the mother effectively “addicted” to her child. This makes evolutionary sense, as a strong bond between mother and child is essential for the child to survive.
Oxytocin is also thought to be associated with long lasting intimate relationships between adults. Oxytocin is released during intimate physical contact between partners, and boosts trust between partners whilst also helping people overcome “social fear” when getting to know each other. A study of “investors” and “trustees” at the University of Zurich suggested that with just a sniff of oxytocin, those playing the role of investors would hand over all their money to phoney anonymous trustees without any guarantee of its return. Those in love would recognise the thought that your partner can do no wrong.
But whilst oxytocin cements close relationships, other chemicals get us to that stage. Lust is driven by testosterone and oestrogen. These hormones encourage us to get out there and meet people, and cause the initial attractions. After lust comes attraction, and this is the stage that most people regard as being love-struck. You are unable to think about anything else and you spend hours daydreaming about that special person. Sometimes you don’t even need to eat or sleep. A group of neuro-transmitters called monoamines are to blame here. You are the victim of dopamine, which is also activated by smoking, adrenaline, which makes you sweat and your heart race, and serotonin, which has been shown to be associated with mental disorders. It would seem that you would have to be mad to be in love. Indeed, studies in Italy have shown that some people recently in love suffer some symptoms of Obsessive Compulsive Disorder. Some even suffered depression!
Another interesting chemical in the brain associated with long-term commitment is called vasopressin. The amount of vasopressin in the brain seems to determine whether or not a couple will remain monogamous. Monogamy, or having only one partner, is not as common among mammals as one may think. Although having monogamous parents could help in child raring, less than 5% of mammals have only one partner. Nature provides a good example of how vasopressin can determine monogamy. The Prairie vole bonds very closely to its mate, whilst its relative, the meadow vole, is promiscuous. It seems that the difference between these species is the amount of vasopressin receptors in the brain. In the prairie vole, when the hormone is released during physical intimacy, there are many receptors with which it can bond, and the deep monogamous relationship is cemented. In the meadow vole, there are very few receptors, and so the feelings of love are not generated and the meadow vole moves on to its next partner.
So it would seem that we are at the mercy of our biochemistry, and that love may indeed give us a mental disorder. In the next few weeks on Mr Science, we’ll have a closer look at what we look for in our perfect partners, and also how to best scientifically woo your lover. We’ll also take a look at internet dating.
Listen to this show here