The Science Behind Smooching

by Curt Kovener

Next Tuesday is Valentine’s Day. Note the singular possessive case though some of my friends may have to spell it Valentines’ Day. And while flowers, chocolates, jewelry and gushy talk might be the expected gifting du jour, some of that may lead to kissing. And after you read this you may reconsider it all.
Made just for kissing: Human lips are different from those of all other animals because they are everted, meaning that they purse outward. But we are not the only species to engage in kissing-like behaviors. Great apes (and I am not referring to the plural possessive friends in the first paragraph) press their lips together to express excitement, affection, or reconciliation.
Scientists are not sure why humans kiss, but some think the answer lies in early feeding experiences. Through nursing and (in some cultures) receiving pre-chewed food from a parent’s mouth, infants may learn to associate lip pressure with a loving act. I wonder if that is where nursing a bottle of beer came from?
Another possibility is smelling a loved one’s cheek has long served as a means of recognition in cultures around the world, from New Zealand to Alaska. Over time, a brush of the lips may have become a traditional accompaniment.
Being close enough to kiss helps our noses assess compatibility.
The earliest literary evidence for kissing comes from northern India’s Vedic Sanskrit texts, written about 2,000 years ago. In those ancients texts it is mentioned lovers setting mouth to mouth. Rather sounds like CPR, doesn’t it?
There is a science of love. But some may say leave it to science to strip romance to its basic common denominator. Dopamine, a neurotransmitter associated with feelings of desire and reward, spikes in response to novel experiences, which explains why a kiss with someone new can feel so special. In some people, a jolt of dopamine can cause a loss of appetite and an inability to sleep, symptoms commonly associated with falling in love. Dopamine is produced in the ventral tegmental area of the brain, the same region affected by addictive drugs like cocaine. But maybe you would have been better off not knowing all of that.
Perhaps Valentine’s Day can help promote good health. Some physicians claim holding hands and kissing reduces levels of the stress hormone cortisol, thereby lowering blood pressure and optimizing immune response.
And in case the dinner conversation lags next Tuesday evening, point out to your significant other that 2/3 of all people turn their head to the right when kissing. If you are with one of those 1/3 left head turners, be careful not to bloody a nose.
Always brush and floss, boys. Evolutionary psychologist Gordon Gallup of the State University of New found that when deciding whether to kiss someone, women pay much closer attention than men do to the breath and teeth of their partner. You mean cavities and garlic breath aren’t a turn-on for the ladies?
And if your smooching gets too passionate, remember: one milliliter of saliva contains about 100,000,000 bacteria.
Now armed with all of these scientific facts, ya’ll have a great day with your valentine.