The world kiss day RIA Novosti says that science knows about his nature.
If you consider a kiss as a touch, its analogue have a variety of animals. For example, fish touch each other mouths and doves beaks, male fruit flies lick the female before mating, cats and dogs RUB against a partner.
Bonobo monkey kiss after fights, to comfort each other, and sometimes just for no reason. Of the primates, chimpanzees kiss more. However, to penetrate the tongue in the mouth of the partner, exchanging saliva, is peculiar only to people. And that is not all. Representatives of about ten percent of traditional cultures is kiss, RUB, lick or sniff partner.
Not to say that a kiss is enough studied. The so-called science of kissing, philematology, founded a few years ago, no specific results have yet been reached. Is that counted the number of muscles involved in kissing, and how much it burned calories. Easy kiss requires two or three muscles, on that the body spends two to three calories. In a passionate kiss involves up to 34 facial muscles and 112 muscles of the body. For this minute kiss burns 26 calories. While kissing is an exchange of fluids and microorganisms that might be unsafe. It is also known that the lips hundreds of times more sensitive than fingertips.
Scientists from Oxford University, Robin Dunbar and Raphael Wlodarski lead three hypotheses why we kiss: it helps to choose a «quality» partner, contributes to the establishment of an enduring attachment, serves as a prelude to sex. Their study confirmed the first hypothesis.
According to the authors of this work, in the moment of the kiss a person receives information about a potential sexual partner. Simply put, the taste and smell of saliva, body help with this. And this is especially true of women, so they appreciate the kiss more than men.
Nice and helpful
An important role kissing played when growing up and the transition to sexual activity, since they are associated with positive emotions. However, this issue is poorly studied. Perhaps, firmly established only among teenagers kissing is very common, with out the sex act.
Some works are devoted to communication and health. The increase in the level of pleasure hormones (endorphins and dopamine) and activation of catecholamines, the signal chemicals in the brain. Also kissing a little increase blood pressure and heart rate, increase the production of saliva. However, the researchers are unable to say what mechanism leads to this, and therefore avoid categorical conclusions.
As for the exchange of microbes — perhaps it could even serve as an evolutionary advantage.
British scientists from the University of Leeds and Central Lancashire has put forward a bold hypothesis that a kiss is something like a vaccination against CMV (herpes family). Primary infection during pregnancy this virus leads to blindness of the fetus or its death, the adult carries the disease quietly. Thus, people could send each other a little bit of the virus so as not to jeopardize offspring. By the way, this method works only with monogamous behavior.