Chemical Communication by Humans: Beyond Pheromones

The concept of being able to communicate emotions & conditions through body smell signals (i.e. signals of a chemical nature, same as other animals), has been at the bottom of lots of research into how humans interact. Pheromones haven't been proven to be a conclusive given yet (though theories abound), but other signals seem to have been at the focus of new research.

via simplovore.com

"To find out, researchers had male subjects watch two movies. One was scary, and the other made viewers feel disgusted. The researchers then collected the participants’ sweat. Female subjects then smelled the sweat, while the scientists recorded their facial expressions. And the women who smelled “fear sweat” actually produced fearful facial expressions. While those who smelled the “disgust sweat” made disgusted faces. The inference is that the chemical compounds impelled the female subjects to remotely experience the same emotions felt by the sweaty males. The study is in the journal Psychological Science." [Jasper H. B. de Groot et al, Chemosignals Communicate Human Emotions]

snippet via Chris Bartelett

The Cat Factor: Toxoplasma Infection Changing our Smell Perception

How does brain chemistry affect our sense of smell? Does your fluffy pussycat have anything to do with it? And what about infections by parasites making our sense of smell and our overall behavior different? 

"In a recent study, Czech scientists gave men and women towels scented with the urine of various animals—horses, lions, hyenas, cats, dogs—which they rated for “pleasantness.” Turns out, men who tested positive for Toxo [i.e.Toxoplasma gondii parasite] found the smell of cat urine more pleasant than men without Toxo[...] French chemists discovered something unexpected in a 1995 sauvignon blanc from Bordeaux: 3-mercapto-3-methylbutan-1-ol, a grape breakdown product that doubles as a fragrant pheromone in cat pee.[...]
Maybe, like with the rats, Toxo is changing something about the way the brain processes cat smells, making the men with Toxo find it more pleasant. Could it be that Toxo is the perfumer par excellance [sic], with privileged access to the very seat of smell itself? Is it a coincidence that “le monstre” of the perfume industry [i.e. Chanel No.5] and the Bordeaux sauvignon blanc both come from France, a country with one of the highest rates of Toxo in the world? "

Thus theorizes a most interesting article on Slate.com writen by Patrick House. One can take issue with the fact that "musk" is used indiscriminately throughout the article for all animalic scents as per perfumery jargon, though we know different; that civet doesn't smell of cat urine per se (rather blackcurrant buds absolute does, as highlighted in our own article the other day); and that Chanel No.5 is really musky but not cat-urinous like, even if "catty" in its attitude. Still, it makes a most interesting case for the way brain chemistry and circuiting is playing a major role in our perception of smells and our reaction to them through minute details we don't take into account day in day out! 

There is also linking to other interesting previously published articles, stating that about 40% of the general population carries the parasite (once you have it, usually asymptomatically, you develop antibodies to it and carry it on for life) and I quote from one of them:

"Infected men [with Toxoplasma gondii] have lower IQs, achieve a lower level of education and have shorter attention spans. They are also more likely to break rules and take risks, be more independent, more anti-social, suspicious, jealous and morose, and are deemed less attractive to women."

"On the other hand, infected women tend to bemore outgoing, friendly, more promiscuous, and are considered more attractive to men compared with non-infected controls.

"In short, it can make men behave like alley cats and women behave like sex kittens".

"Another study showed people who were infected but not showing symptoms were 2.7 times more likely than uninfected people to be involved in a car accident as a driver or pedestrian, while other research has linked the parasite to higher incidences of schizophrenia." [from same source]

Interesting, don't you think? 

Now, I happen to know I have been infected with this particular parasite in the past (probably from eating rare meat, a habit that French people also take to with a vengeance making them one of the people with the highest rates of Toxo in the world) and I can attest these things:
I have always liked cats, though never owning one, and always found their urine sharply ammoniac and very intense (i.e. not exactly pleasant). I have not  developed a more outgoing nature compared to previously. Nor have I noticed a sharper interest in male attention that is irresponsive to other accouterments of my appearance. Can't say I have ever being involved in a car accident, which is rather miraculous for living where I live (where car accidents are frequent and driving is aggressive) and my risk-taking is just about level to what it used to be. 
I may have become a little bit more aloof though, being crankier compared to my puppy fat years, i.e. cattier. 

What do you think? 

pic via wired.com