Valentine hearts are everywhere at this time of year as people celebrate the power of love. But forget about your heart: love doesn't happen there, it is a drama played out in your head.
You can put it down to romance, but it is the brain that gives you that feeling of euphoria, the butterflies in your stomach and the sweaty palms when you meet that special person. And it is your brain deciding if you are overwhelmed by love at first sight.
Brain chemistry goes haywire, and your release of hormones goes into overdrive when your eyes meet those of another across a crowded room, says Dr Stella Vlachou, director of the behavioural neuroscience laboratory at the school of nursing and human sciences in Dublin City University. She knows just how much of an impact love can have on the human brain.
My chemical romance
First it throws your brain-signalling chemicals, the neurotransmitters, off balance, she says. More dopamine is released, an important substance in the pleasure and reward systems of the brain. And serotonin is reduced, a neurotransmitter that is related to mood, appetite, and sleep.
Your body responds by rapidly changing the hormone mix, for example increasing the release of the hormone adrenalin. This immediately leaves you with damp palms, shortness of breath, light-headedness and dizziness, even before you have had a chance to walk across that room.
The hormone oxytocin is also released, which plays an important role in the neuroanatomy of intimacy, childbirth and lactation. It is sometimes called the “bonding hormone” because of its impact on relationships, says Dr Vlachou.
The brain itself also changes from its normal routine, she says. “There is an activation of specific areas of the brain and a reduction in others.”
Activity in the brain’s reward system – including the orbital frontal cortex, the nucleus accumbens and the hypothalamus – rises when couples first meet and fall in love, and together they provide feelings of pleasure and reward. A very similar brain response occurs when people take drugs such as cocaine.
Other important areas of the brain are down-regulated, including the amygdala, an area that controls emotional response to things such as fear. The prefrontal cortex also eases back in its role in overseeing cognitive function but also decision making and judgment. It becomes much harder to say no.
Heightened bonding and reduced judgment seem a recipe for a tryst that could lead to something else. “It would be a way to secure that there will be reproduction. Work at University College London by Dr Semir Zeki showed that the physiological response acts this way because it makes reproduction more likely,” says Dr Vlachou.
“That is probably why these responses are universal in the human population. Reactions are heightened and controls are reduced. It seems as if the brain is controlling us, rather than us controlling the brain.”
Ironically, many of the changes sparked off by that old black magic called love are often seen in another context. There are similarities between the symptoms of being in love and those associated with psychological disorders, she says.
“If you are in love it is almost like you have a psychosocial disorder.”
There are the mood swings, from euphoria to depression, the obsessive-compulsive checking for texts and the low when a love interest has not phoned in the past two minutes, she says.
Battle of the sexes
The fact these symptoms are repeated again and again across the human population confirms we have evolution to thank for all of this, suggests Dr John Mackrill, a lecturer in physiology at University College Cork.
“Some of this is beyond your control: it is the evolutionary battle of the sexes,” he says. “What is love, attachment or sexual gratification? It is difficult to define, but of the 167 human cultures surveyed across the world, 150-odd favoured monogamous relationships. ”
This does not mean men and women don’t have distinct agendas. “There are certainly gender differences,” says Dr Mackrill. Men respond to beauty because it equates to healthy genes, while women respond to success in terms of resources such as food and an ability to get it. Men want children as a way to spread their genes, while women want their children to survive, not just their genes.
There is a meeting of minds to a degree, however. “The concept you come across again and again is the fact that human children need lots of care and need to be protected in order to pass on genes.”
This is facilitated by monogamous relationships. It seems complex, but somehow the human species survives by doing what comes naturally when we fall in love.
LOVE AT FIRST SNIFF
Women who want to find the ideal mate should start paying less attention to what their eyes tell them and respond to what their noses have to say about a man.
Dr Rob King of University College Cork’s school of applied psychology leads a research group looking at fertility and wellbeing. In particular he is looking at how female sexual response varies from one partner to another and whether this in turn strengthens or weakens bonding between a couple.
Initially the researchers assumed that what women want in a male partner is plenty of muscles and a high degree of aggression, and this would in turn lead to a heightened sexual response. The women gave their verdict, but many kept suggesting that another attribute should be added – a man’s natural smell – and so this was added to the list of questions.
“Smell is interesting, because it is a signal of genetic compatibility,” says Dr King. Having an appealing smell is the “biggest single predictor” of sexual compatibility. Women also favour men who are dominant and confident but also considerate and competent, he says.
He warned, however, that applying scents and sprays to attract a woman could be counter-productive. “Masking odours with cheap stuff is not a good idea.”
He had another unorthodox suggestion for women: if you want confirmation that you have the right guy, then go off the pill for a time while making use of other precautions.
“Taking the pill changes a woman’s sense of smell. A significant number of people change their partner preference after coming off or going on to the pill,” he says.
