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Love in the time of neuroscience

Love in the time of neuroscience
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First Published: Fri, Feb 13 2009. 09 52 PM IST

Decoding the molecules: We know very little about why and how we fall in love. Illustration: Jayachandran / Mint
Decoding the molecules: We know very little about why and how we fall in love. Illustration: Jayachandran / Mint
Updated: Fri, Feb 13 2009. 09 52 PM IST
Is falling in love a poetic fancy or is it nature’s way of perpetuating our species?
Is it illusory, as common sense would suggest, or is it a chain of biochemical events in the brain that is now visible as blips in brain scans?
Decoding the molecules: We know very little about why and how we fall in love. Illustration: Jayachandran / Mint
Cynics would say go fall in love and figure it out. Philosophers, swinging to extremes in their definition of love, from animal passion to the ultimate conqueror, at least agree on one point—it’s of paramount importance to mankind.
But scientists, known for their reductionism, would say let’s break it down to its components and see how molecules relate to mushy behaviour. In doing so, they are discovering, for the first time, that the complex human emotion we call love is a mesh of neural circuitry, hormones and genes. It turns out the chemistry between couples is due to the release of chemicals in the brain at different stages of romance—attraction, lust and attachment.
So, when Hasse Walum at the Karolinska Institute in Stockholm and his colleagues said in September that they had found an association between variations in a gene and human pair-bonding among men, it made a splash. People were quick to dub the gene, which modulates the production of the hormone vasopressin, an indicator of “husband material”.
Walum’s study on people who spent at least five years in heterosexual relationships showed how men with variations in this gene reported corresponding variations in the quality of the relationship. Those with one particular variant—let’s call it the “poor-bonding” gene—have twice the odds of being a bachelor or having a marital crisis than men who lack it. They also reported low scores on the Partner Bonding Scale, a standard psychological test, and their spouses confirmed dissatisfaction in their relationships.
Similar studies on women are on the anvil. Walum tells Lounge he has planned several studies for the spring and summer, which include investigating if variations in a gene that codes for oxytocin—a hormone known to influence female pair-bonding—are associated with how closely women bond with their partners.
Spray and cuddle
Walum’s forthcoming study will be closely watched since oxytocin, the so-called “love hormone” released in the brain during orgasm and childbirth, is already under test. Last year, Adam Guastella at the Brain and Mind Research Institute, University of Sydney, ran a unique trial to test if sniffing oxytocin during counselling sessions could help incompatible couples resolve their differences.
A nasal spray for couples to let Cupid strike one more time?
“I haven’t looked at the data yet, but the trial ran very smoothly,” says Guastella, whose argument is to use oxytocin to improve the way in which couples read each other’s emotions and respond to them. “We hope that this approach may improve communication so that couples can resolve disputes more effectively,” he says. This, he believes, even holds for couples wanting to separate.
With such a potent chemical around, how can entrepreneurs not feel the pull? A Florida-based online company, Vero Labs Llc., is already shipping bottles of a body spray called Enhanced Liquid Trust that largely contains oxytocin. Its claim: “It’s the world’s first trust-enhancing body spray, specially formulated to increase trust in you.”
Scientists dismiss it as a marketing gimmick. At present, nasal spray is the only way of administering it, though Guastella says options such as a capsule are being explored. He adds that administering a small dose of oxytocin, even nasally, on a small number of occasions will not make people fall in love or have a long-term influence on their bonds.
That brings genetic determinism back in focus. Maybe humans are hard-wired for love or a lack of it. Veteran singles agree that genes could play a role, even if only a wee bit.
A networking engineer with a multinational company in Bangalore and a bachelor, S.N., 41, thinks it is partly genes that govern romance, bonding and commitment for familial responsibilities—and partly the institution of marriage itself which leads people like him to shun love (and marriage).
“We may be reading too much if we connect all this to a single gene. Marriage is a relatively recent practice, perhaps less than 20,000 years old, and possibly people remaining single started only after marriage rules were put into place,” he argues.
But N.M., a senior journalist in New Delhi who got married in his mid 40s and was divorced within a year, thinks some people are “hard-wired for a bad marriage”.
With three siblings having “normal”, happy married lives, N.M. thinks Walum has hit the nail on the head. “In such people (singles), the degree of craving for marriage or physical gratification is less; a lot of men can’t help but give up a lot for a relationship.”
Evolution of love
As scientists bare the mystique of love, an emotion traditionally thought to be uniquely human, it’s becoming apparent that once again, animals are coming to their aid in understanding humans. For much as science wishes to unravel scientific and psychological mysteries, it is bound by ethics to restrict certain experiments in humans.
Experts say that just as animal models helped demystify evolutionarily conserved emotions such as fear and anxiety, they are now throwing light on love.
“It is true that most of what we know about social bonding and molecules like oxytocin and vasopressin comes from prairie voles,” says Larry J. Young, a social neurobiologist at the National Primate Research Centre, Emory University, in Atlanta. Prairie voles are mouse-like rodents which belong to the exclusive club of mammals that are engaged in monogamous relationships, and hence are now being extensively studied for understanding human relationships.
Young’s wide-ranging work in prairie voles shows a fascinating overlap between the brain regions of voles and humans when they are engaged in pair-bonding and love. He has shown how introducing oxytocin in female prairie voles’ brains gets them quickly attached to the nearest male. This happens because the hormone turns on parts of the brain that are involved in the reward system, acting on the same neural circuitry that gives pleasure and provides a high during the intake of nicotine, drugs such as cocaine, and others (this might explain, to some extent at least, why love is addictive).
Similar brain activity is seen in humans when they see their lovers’ photographs or when mothers view their children’s images. But there are the usual caveats: “We cannot be sure that these molecules (oxytocin, vasopressin) are also involved in human bonding, or even in other monogamous species. Hopefully, other investigators will examine this,” says Young. He, however, agrees oxytocin “seems to tune our brain into the social world” and enhances the ability to infer the emotions of others.
Young and Walum represent the two ends of the spectrum, pushing the boundaries in animals and humans, respectively, says Sumantra Chattarji, a neurobiologist at the National Centre for Biological Sciences in Bangalore, who studies memory, anxiety and stress disorders in animal models.
“Young’s work is stunning, and with Walum’s research, it provides a wonderful convergence (of animal and human data),” says Chattarji. According to him, this is the rare “golden case” where studies at the cellular level in animals and at the behavioural level in humans are together advancing the neurobehavioural understanding of love and bonding.
Love in a pill
Megabucks are waiting to be made once science is on firmer ground. As imaginations run wild, so can human desire. A drug to increase or decrease love; a diagnostic to test how happy people will be in future relationships, or even a test of compatibility for likely suitors?
“I doubt that the development of drugs to enhance or diminish love will ever become the focus of bona fide drug companies,” Young says. As a scientist, he doesn’t think it right to pursue the development of such drugs. “But I would not be surprised if companies do exploit the science of social bonding to sell drugs that promise to increase or decrease love,” he concedes.
As definitive as the chemistry of love is getting, it will be a slippery slope for science in terms of holding on to ethics. Helen E. Fisher, a biological anthropologist and human behaviour researcher at Rutgers University in New Jersey, has proposed three stages of love—lust, attraction or romantic love, and long-term attachment (Fisher is also the chief scientific adviser to Chemistry.com, an Internet dating and relationship site which is a subsidiary of Match.com).
Incidentally, each stage of love triggers a set of chemicals in the brain. Lust is related to steroid hormones such as oestrogen and testosterone. Attraction sparks off the reward system (remember the intake of addictive drugs?) and is related to the hormone dopamine that impacts our emotional response and the ability to experience pleasure and pain. Attachment is shown to release hormones such as oxytocin and vasopressin, facilitating those feelings of security and social comfort that go beyond sexual attraction.
Surely these chemicals have some overlap in the brain, just as there is in emotional life. After all, people do sometimes fail to decipher their own feelings. Author Douglas Yates says, “People who are sensible about love are incapable of it.” We can even find evidence next door when sometimes, even after being courted by the best suitors, people are unable to fall in love, much to their bewilderment.
However, neuroscience does seem to have an answer to the fabled question of why love is blind or why fools fall for love. Functional magnetic resonance imaging shows that when in love, humans’ pre-frontal cortex, the part of the brain usually involved in making decisions and social judgements, is shut off (what this means evolutionarily is another story altogether).
Love-in-a-pill, trust-in-a-bottle and match-making-in-a-kit may eventually be pursued by scientists. One can even imagine—something very much in the realm of science fiction now—that couples whose relationships have failed will go to court saying “I goofed up because I forgot my love-pill”.
In reality, ethics and morality will have a larger role. “We have plenty of examples where science has opened the can of worms; physics is full of them,” says Chattarji.
People at the forefront of this discipline are pretty cautious. “We really know very little about (the) neurobiology of love,” Young adds. It’s much more complex than the few molecules and circuitry discussed above—we don’t know the brain circuits that are involved, nor do we understand what molecules are active in which circuits. “In fact, we may never figure this out because it is unethical to do the kind of experiments in humans that would be necessary to figure it out.”
The social payouts, though, would be immense for disorders such as autism, where drugs could enhance social relationships. In fact, Guastella’s group is already studying the effects of oxytocin nasal spray on social communication in young autistic people.
But we do know enough to improve our love lives. No new-age drugs involved here, just old-fashioned behaviour such as companionship, generosity, affection or even spending time together. Reason: These acts naturally trigger oxytocin release in the brain.
Flowers, kisses and hugs are more potent than pharmacology.
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First Published: Fri, Feb 13 2009. 09 52 PM IST