Falling in love and staying that way is no doubt a great feeling. And here’s some good news for those who’ve been wondering how long their relationship is going to last. By simply peering into the brain maps of a couple in love, scientists can find out whether an early intense passion will end in a lifelong affair.

For those hoping to mark Valentine’s Day with a degree of certainty this year, science is there to help. It tells you everything — from what makes a couple tick to what to wear to impress a date. Scientists, a slew of research papers shows, are seeking to understand the underpinnings of the complex neurobiological phenomenon called love.

“Science has just started to skim the surface of this fascinating subject,” says Semir Zeki of the University College London, one of the early neurobiologists to enter this unchartered territory.

Scientists today know which regions in the brain brighten up when people fall in love, thanks to advances in brain mapping techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET).

“What research (in the last decade or two) has shown is that a state as subjective as that of romantic love can be studied scientifically in terms of brain areas engaged, and it has also been able to measure the strength of activity in these areas in relation to the declared intensity of the experience,” says Zeki.

While studying the neurobiology of love, both romantic and maternal, remains a passion for Zeki, his counterparts at Stony Brook University in New York are beginning to unravel brain mechanisms that can tell whether a budding love affair is destined to be shortlived or lifelong.

In a paper published in Neuroscience Letters last September, together with their collaborators from China, the Stony Brook researchers showed that the fate of a relationship can be determined by studying the brain activity of the two partners.

But all in-love brains aren’t similar. Some years ago, a team led by Xiaomeng Xu — an author of the Stony Brook study and now a postdoctoral fellow at the Brown University School of Medicine — conducted fMRI scans on 18 young Chinese adults, both men and women, who were in the early stages of love.

All participants displayed clear signs of love — when they looked at the face of their beloved, a flurry of activity was triggered in the areas of the brain involved in reward and motivation. But the researchers identified subtle differences in the individual brain scans.

So they followed up with 12 of the 18 original participants 40 months later to see how the then budding relationships had panned out for them. Out of 12, six had continued in the same relationships, while the other six had fallen out with their partners.

Even though the sample size was very small, the scientists found a surprisingly strong correlation between characteristics in the original brain scans and the status of the relationship, offering an idea of the indicators of lasting love. They also picked up signatures in the brain maps to substantiate what scientists thought for long — that, over time, passionate or romantic love evolves into a companionable love whose hallmarks are deep friendship, easy companionship and sharing of common interests, not necessarily sexual desire and attraction.

“Mainly we found that people in longer-term committed relationships showed more activation of the brain than those newly in love,” says Bianca Acevedo, a psychologist and co-author of the study.

People’s mating preferences have long been a subject of enquiry. It’s widely believed that men, being the less investing sex (they don’t bear or nurture children), are less selective and hence seek short-term relationships with multiple partners. Women are more selective. In addition to physical attributes, they look for parental abilities in their long-term partners.

For his doctoral degree, Ohad Szepsenwol of Bar Ilan University, Israel, wanted to test whether this “one-size-fits-all” strategy works for everybody. The study, to be published in the June issue of the Journal of Research in Personality, offers fascinating insights.

The study divides people into two categories: sexually hyperactivated people and less hyperactivated ones. Sexually hyperactivated people experience a high desire for sexual encounters but at the same time feel inadequate in the sexual domain, which makes them anxious in sexual situations, says Szepsenwol.

But by keeping the sexual system in a constant state of activation, they pay an emotional price — high anxiety and fear of failure. “Every sexual failure has severe consequences for their sense of self-worth, and exacerbates their anxiety,” he says. They also tend to go in for more short-term relationships than the less sexually hyperactivated people, he adds.

Scientists even have advice to give on what one should wear on Valentine’s Day. If you are a young woman and want to increase your sexual attractiveness when you are out with your date, you should wear red, says Sascha Schwarz, a social psychologist with the University of Wuppertal in Germany.

A recent study by Schwarz and colleagues showed that men of all ages love to see young women in red clothes. However, tough luck for middle-aged women: the colour doesn’t really help, Schwarz says.

The scientists asked 120 participants (half of them young) to rate both young and middle-aged women in red as well as in white backgrounds. The participants found the young women in red more attractive. The scientists also found that the effect the colour has on them works at a sub-conscious level and the beholder is often not aware of it.

Over the years, scientists have been able to understand the chemical changes that happen in the brain when one is in love. The brain areas that get activated in response to romantic feelings are largely those that contain large concentrations of a neuro-modulator — dopamine — that is associated with reward, desire, addiction and euphoric states, says Zeki. The fact that romantic love can help release copious amounts of dopamine is even prompting scientists to explore whether it can be used to treat addictions such as smoking.

“The release of dopamine puts one in a ‘feel-good’ state,” he says. A lover’s brain releases two other neuro-modulators — oxytocin and vasopressin.

Oxytocin, the brain chemical which works as a trigger for love and affection in females, is stored in the pituitary gland to be discharged into the blood. Interestingly, it is produced not only in maternal love, but also in romantic love. Oxytocin, quite like vasopressin in males, is released in the blood during sexual orgasm.

According to Zeki, a lover’s brain works less in the area that is used for judgement. “This makes us understand better why we tend to be less judgmental about those we love,” says Zeki.

And you thought science was all fusty?

To look sexy, wear red

If you are a young woman and want to increase your sexual attractiveness when you are out with your date, you should wear red

Tough luck for middle-aged women: red doesn’t really help