Why do we kiss ? [interesting facts]

Kissing is part of our daily lives. So much so that I think – not many – have stopped to ask themselves the question: Why do we kiss? “philematology” is the scientific study of kissing (philos in ancient Greek = earthly love).

The Biochemistry and Physiology of the Kiss

via GIPHY

During a kiss, couples exchange  9 mg of water, 0.7 mg of protein, 0.18 mg of organic compounds, 0.71 mg of fat, and 0.45 mg of sodium chloride, along with 10 million to 1 billion of bacteria according to estimates. When  kissing simply  we use only two muscles, burning only 2 to 3 calories, while in a  passionate kiss : we involve up to 34 facial muscles along with 112 postural muscles and burn around 26 calories per minute.

The Original Theory of Why We Kiss

via GIPHY

The primate mothers chewed food for their babies. However, as evolution continued, kissing began to be used to  transmit information about  a couple’s biological compatibility. This through chemical pheromone signals, as well as promote  social bonding  and  express love , with the ultimate goal of procreation.

With kissing, couples can get close enough to each other to  evaluate essential characteristics  of each other, none of which are consciously processed. Although the  vomeronasal organ  or Jacobson’s organ  is believed  to be responsible for detecting pheromones  and communicating the chemical environment to the brain of animals – research indicates that  it is a vestigial and inactive organ in humans .

Compatibility, Genetics and Hormones

One study  found that when  women were asked to smell different men’s T-shirts and choose their favorite,  the choice was not made at random, but was based on the man whose  Major Histocompatibility Complex  (MHC) (a series of genes involved in the immune system)  was different from one’s own. The importance of this is that different HSCs mean less immune overlap indicating  healthier offspring.

While men are not selective in terms of kissing, women are very picky.  This is because on an evolutionary level women were looking for a partner to raise their children. And kissing could be an unconscious but accurate way for them to assess a man’s immune compatibility. This before investing too much time and energy in him.

why do we kiss from men perspective

On the other hand, men would have sex with women without kissing them beforehand. Just as with women who are not good at kissing, most women will never have sex without kissing first. Men tend to initiate the French kiss , research suggests this is because their saliva  contains testosterone and  this  increases their partner’s sexual desire.  Additionally, men are able to detect a woman’s estrogen level, which is a predictor of her fertility.

The Healthy Consequences behind why do we kiss

Hormonal levels change after kissing. Specifically, cortisol (stress) levels decreased  in men and women after kissing. And the longer the couple spent together, the lower their stress hormones. Interestingly, oxytocin levels increase in men, however, they decreased in women. One theory is that  women need more than a kiss to stimulate attachment and bonding.  Kissing increases testosterone, which increases sexual desire, and also increases dopamine, promoting romantic love, and oxytocin (men only), which promotes bonding.

Other benefits include  a modest increase in blood pressure and heart rate which  helps our heart health . Will there be anything tangible of that universal symbolism of relating the heart to love? On the other hand, the increased saliva produced during active kissing  helps prevent tooth decay , and men who kiss their wives in the morning live 5 years longer on average and also earn more money.