The Science of Kissing

Every romance reader (heck, every person) knows that the magic of any romantic relationship starts with a first kiss. I recently came across some fascinating information by Dr. Reese Halter on the “science” of kissing. This is part of his blog, reprinted with his permission:

“When the first kiss works, it’s powerful all right, as over 90 percent of lovers, irrespective of age, can remember exactly where and when it occurred. Moreover, that first kiss is a dealmaker or breaker because over 60 percent of first kisses, for both men and women, are a failure, terminating any chance for romance.
            Well before that first kiss occurs, the eyes are conveying important information to the brain, which in turn has a tremendous influence upon our feelings associated with love. Next time you get a chance watch how new lovers look at one another – it’s thrilling.
            After the eyes have helped set the mood in the brain, just prior to approaching that first kiss, the prospective lover involuntarily tilts his or her head, either to the right or left. It turns out that about two-thirds of us tilt to the right.
            It’s not right-handed related but rather correlated to head tilt direction while in utero as the fetus moves and tilts its head. Also, over 80 percent of nursing mothers cradle their babies to the left, thus the infant must turn its head to the right. Conditioning for feelings of love, affection and sustenance clearly begin very early in our lives.
            Assuming that first kiss feels just right, then five of the 12 brain nerves are now into overdrive including hearing, seeing, smelling and tasting. Individually and collectively, they affect the expression on the lover’s face.
            As the kiss heats up, blood vessels expand to allow more oxygen to the brain, breathing becomes deeper and irregular and pupils dilate (likely explaining why many lovers close their eyes).
            Invariably, there will be tongue contact, more often than not initiated by the male - but more about that later. The tongue allows us to sample our partner’s taste with the assistance of over 9,000 little bumps, or taste buds, spread across its surface.
            Now all five senses are sending messages to the brain; that is, tens of billions of nerves are firing rapidly throughout the body.
            Lips are very sensitive to pressure, warmth and cold; they contain the highest concentration of nerve cells on our body. There are over 100 billion complex nerve cells liberally spread throughout the lips. They are the gateway to tiny neurotransmitter molecules that help trigger hormones including dopamine, oxytocin, serotonin and adrenaline.
            That first passionate kiss causes dopamine to spike throughout the brain. It’s a give-me-more insatiable gene all about pleasure; when we first fall in love and have those over-the-moon thoughts, that’s dopamine. Incidentally, when we first fall in love it affects the same part of the brain – giving us a craving just like cocaine. It also causes energy to elevate, loss of appetite, sleeplessness and even intoxication.
            Oxytocin is a love hormone that is crucial in promoting affection and attachment so that when dopamine wanes, oxytocin surges. That’s why a kiss, hug or tender caress helps to maintain a strong sense of attachment for lovers.
            Serotonin controls our emotions and movement of information to the brain, and those obsessive feelings (like dopamine) and thoughts about our new lover. When that first passionate kiss brings love into our world, the high levels of serotonin mimic those associated with obsessive-compulsive disorder.
            That first passionate kiss can cause some people to experience a sensation of weakness-in-the-knees due to high levels of adrenaline, which are also spiking in the brain.
            Women intuitively use that first kiss to assess whether a male is healthy and possessing ‘good-genes.’ If that first kiss feels and tastes good, that’s an excellent start in a bonding relationship.
            The other important link in determining whether that first kiss makes the grade is body scent. Not surprisingly the highest concentration of scent or sebaceous glands are near the nose, face and neck. Each of us has a unique scent and the human nose is able to detect over 9,000 different molecules. When you press your nose over your prospective lover’s neck or jaw-line, instinctively only you’ll know if their scent is just right.
            Lastly, there’s a valid evolutionary reason why men slip women a wet, sloppy tongue kiss. Male saliva contains testosterone, a hormone in short supply in females. Just a few male testosterone molecules raise women’s libido, readying that passionate scene for intimacy.”

Thank you, Dr. Halter! As romance authors and readers here at Fierce Romance, we all know how important that first kiss can be, but you’ve opened our eyes to the fascinating science behind the emotion of kissing. You can read more about Dr. Halter at:

What about you? How important is a "perfect"first kiss to a relationship? I'd love to hear about your experiences!


Anonymous said...

Wow, this is fascinating stuff! And it really reminds romance authors of how they should pay attention to the five senses: touch, sight, smell, taste... even sound!

Great blog, Leigh!

Tanya W

Leigh Court said...

Thanks, Tanya. And yes, the five senses can add a lot of depth to any romantic scene.

Thanks for your comment!

Christine Ashworth said...

Wow, Leigh - what a bunch of excellent information! I can just see a female scientist start to clinically analyze that first kiss before her wits get swept away, lol...thanks so much for this!

Leigh Court said...

LOL Christine, it sounds like you have the start of a very funny & exciting scene!

Thanks for the comment!

Lynne Marshall said...

Fascinating! Thank you so much for sharing this information. I have bookmarked this blog and the good Dr.'s website. :)

Alyssa Kress said...

This is fascinating, even though I think it's a little silly when scientists try to analyze love. And that male testosterone on the tongue bit isn't going to do a thing for me if I didn't want it there in the first place. Maybe it would give a woman the oomph to push the guy away!

Kathy Bennett said...

Wow! Who knew all that was going on during a first kiss?

I wonder if it applies to a lesser extent for subsequent kisses? Guess I'll kiss my husband and try to find out!

Kate Willoughby said...

Very interesting reading. My first thoughts were actually what Alex, the hero in my WIP, would say to the woman he's about to pursue in earnest.

"You know what, Claire? You wanna know why that kiss we shared two years ago was so amazing?" He'd look at her with a boyish grin on his face. "It's because my spit has man stuff in it. Otherwise known as testosterone, baby. And your body can't help but respond to it."

"But don't all guys have testosterone spit?"

Alex would pause then. He doesn't always think before he speaks. "Well, if you want to get technical about it..."

Robena Grant said...

Wonderful! Thanks for sharing.

Martha O’Sullivan said...

So there IS a science to everything -- even love! I remember my first kiss with my husband and this is all so true. Amazing. Thanks for sharing.

Sam Beck said...

Well, shoot...first kiss should be mouth-on-mouth?! ;)

Kidding aside, the article was very educational!

Leigh Court said...

Thanks for your comments everyone! I can see this blog is sparking a few "kissing scene" ideas, LOL!