14 DAY TRIAL // Sexual attractiveness is much more than a look. Even if 80 % of the information we receive about our partner is visual, there is more.
Researches have shown that women who look more attractive also smell better. At least at certain periods of the month, while symmetrical men, found very attractive by women, do smell better.
Evolutionary biologist Randy Thornhill of the University of New Mexico put female subjects to rate their impressions of the scents of male pitarms. The scent of a symmetrical man was more attractive, especially if the woman was during the menstruation. Of course, this was subconscious.
Women did not report smelling anything sometimes, yet they were attracted to that shirt or scent.
A 2002 research discovered that women choose the scent of men with closer genes to theirs than of genetically dissimilar men. This could be linked to pheromones, molecules signaling the reproductive quality of the individual.
The sex brain area of gay men has been found to react similarly to women's at men's scent.
In the end, humans possess 1,000 genes linked to olfaction and only about 300 genes for sight and this could explain the importance of perfumes and perhaps pheromones, in our sexuality.
Most mammals use pheromones during courtship. But evolutionary biologist Jianzhi Zhang of the University of Michigan believes we have lost the pheromone's use.
He thinks we lost the pheromone perceiving the gene's function about 23 million years ago when monkeys in Africa and Asia started to use color for sexual signaling: a reddened female's bottom signals readiness for mating.
"With the development of a sexual color scheme, you don't need the pheromone sensitivity to sense whether a female monkey is ready to mate. It's advantageous to use visual cues rather than pheromones because they can be seen from a distance." Zhang said.
Pheromones are detected by a special organ called the volmeronasal organ, located on the roof of the mouth, which humans now lack. That's why from lions to bulls, mammals have to make a grimace called flehmen to sniff pheromone-loaded air with the roof of their mouth.
"After our ancestors began to see color, a gene important in the pheromone-signaling pathway suffered a deleterious mutation, making it impossible for the scent signals to reach the brain. Imagine a train, leaving from Los Angeles to New York, discovers that the tracks in St. Louis are destroyed." said Zhang.
The classical pheromone pathway in African-Asian monkeys, apes and humans is non-functional, but pheromones seem to be still produced and some researchers say we are still influenced by them.