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The science of love

It won’t be roses that some Irish girls will be smelling this Valentine’s Day in Dublin but sweaty T-shirts — and that might turn out to be a more guaranteed way to a lover’s heart.

In the interest of science, a group of men have volunteered to peel off their T-shirts for a sniff test by young women visiting a "love laboratory" at Trinity College Dublin (TCD) on Feb. 14. Aoife McLysaght, a curator of the exhibition, bubbles with enthusiasm when describing how the sense of smell can indicate whether a person is a suitable reproductive match. As an experiment to show that lovers prefer mates with different genes, she and her colleagues persuaded 30 male volunteers to wear T-shirts washed in odorless detergent for two straight days so they leave their unique “scent.”

“By smelling a T-shirt a woman can establish if the wearer is the right man for them,” said McLysaght, a lecturer in the School of Genetics and Microbiology at TCD. “Women will tend to prefer the T-shirts of men with a more diverse immune system. If we try to rationalize why, it is because the offspring would be more robust.”

Scientists in white coats at the love lab in the Science Gallery in central Dublin Wednesday were busy taking DNA samples to show a correlation between those of sniffers who find the T-shirt odor attractive and those who have different immune genes. In scientific terms they will be seeking with their noses traces of the pheromone androstenone, which in male testosterone is a strong indicator of certain immune genes.

It doesn't sound very romantic, but then the whole point of the exhibition is to show that romantic love is actually the result of a scientific interaction. A person’s genetic makeup has an influence on whether you fancy them or not. The heart goes boom-be-de-boomp not because of stars getting in your eyes but because of something in the nasal cavity. The female who likes the smell of a T-shirt is more likely to hit it off with the wearer than another who finds it neutral or repulsive.

In fact, said McLysaght, there is a lot of unconscious smelling going on when boy meets girl. There is a function in the nasal cavity that recognizes diverse genes. “It’s amazing,” she exclaimed. “How can you smell somebody else’s genes, what’s going on here?”

She pointed out with amusement that in this respect we are not much different from mice, which attract mates the least like them in terms of their immune system genes. So don’t bring flowers to woo a lover, bring a copy of your DNA. Teenagers at a disco might not know it, indeed it might be the last thing on their mind, but what drives them to fancy someone is a gene-driven desire to have healthy children.

The love lab is also experimenting with the effect of whispering sweet nothings, gazing into one’s eyes, walking in a sexy way and speed dating. On Valentine's Day it will provide a blindfold Valentine’s dinner with the four aphrodisiac courses served in complete darkness — which might only prove that love really is blind.

In one corner of the exhibition there is a bed behind transparent curtains. Physics graduate Gary Murphy demonstrates how partners separated by distance can communicate by using a custom computer projection system to draw on each other’s bodies with light “allowing a new kind of synchronous communication.” Well, whatever turns you on — which is, of course, what the exhibition is all about.

Trinity College Dublin

Aoife McLysaght (front) with her team of researchers in the School of Genetics and Microbiology at Trinity College Dublin,  David Gonzalez Knowles, Takashi Makino, Daniel Murphy, Kirsten Bratke and Asa Perez-Bercoff. (Trinity College Dublin)