Humans assume what attracts them about someone is the obvious: nice eyes, physique, perhaps personality.
But smell also plays a big role – one written in your genes, according to one recent study.
“We know that humans release olfactory signals,” said Christine Drea, an associate professor of biological anthropology and anatomy at Duke University. The question, she said, is to what extent do we use those cues when selecting a mate?
Drea, who studies scent cues in primates, arranged for a group of women to smell shirts worn by a group of men, then asked each woman which scents they found most attractive.
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“There is evidence that women will pick the shirt worn by the man with the best genetic complement to her own genetics,” Drea said.
For example, if your genome protects you against a certain set of diseases, a good genetic complement will carry genes that protect against another set of diseases – providing your offspring with an immunity double whammy.
Scientists have not identified the array of chemicals that make up human scent, but are inching closer by studying other primates.
Last month, Drea and a team of Duke researchers announced they had mapped the scent chemistry of the ring-tailed lemur.
Male lemurs have glands on their shoulders that manufacture a musky scent. When they wish to mark their presence, they scratch a tree, then rub their scent into the wood.
Not only does the scent identify the lemur, it also contains information about that lemur's family tree.
“Diverse genetics are reflected in a diverse chemical signal,” Drea said. “In humans and in lemurs, in-breeding has genetic consequences, and diverse genetics are really advantageous.”
The question that remains is to what extent the lemurs use these smell indicators to make their mating decisions.