This paper looks at neural imaging responses of subjects who observe, in photographs, various kinds of kissing. The two main variables are who is kissing (by gender) and the nature of the kiss.

One of the authors is my friend and colleague, Sheril Kirshenbaum. She wrote the book on kissing. No, seriously, she wrote this book, which I’ve reviewed here.

From the abstract of the paper:

With a few exceptions, the literature on face recognition and its neural basis derives from the presentation of single faces. However, in many ecologically typical situations, we see more than one face, in different communicative contexts. … Although there is no obvious taxonomy of kissing, we kiss in various interpersonal situations (greeting, ceremony, sex), with different goals and partners. Here, we assess the visual cortical responses elicited by viewing different couples kissing with different intents. The study thus lies at the nexus of face recognition, action recognition, and social neuroscience. Magnetoencephalography data were recorded from nine participants in a passive viewing paradigm. We presented images of couples kissing, with the images differing along two dimensions, kiss type and couple type. We quantified event-related field amplitudes and latencies. In each participant, the canonical sequence of event-related fields was observed, including an M100, an M170, and a later M400 response. The earliest two responses were significantly modulated in latency (M100) or amplitude (M170) by the sex composition of the images (with male-male and female-female pairings yielding faster latency M100 and larger amplitude M170 responses). In contrast, kiss type showed no modulation of any brain response. The early cortical-evoked fields that we typically associate with the presentation and analysis of single faces are differentially sensitive to complex social and action information in face pairs that are kissing. The early responses, typically associated with perceptual analysis, exhibit a consistent grouping and suggest a high and rapid sensitivity to the composition of the kissing pairs.

Interesting research, part of the bigger picture of how human perception operates in an important social context. I asked Shiril Kirshenbaum for a quick comment and she told me that one of the most interesting parts of this work is “that usually we think of science writing as something that happens after research or discovery. But here we have a nice example demonstrating that the relationship can go both ways where new science has been driven by the storytelling.”

A kiss is not a kiss: visually evoked neuromagnetic fields reveal differential sensitivities to brief presentations of kissing couples. 2015. Cogan, Gregory, Sheril Kirshenbaum, Jeffry Walker, and David Poeppel. NeuroReport, August 18, 2015.

I went out with a friend. We were both between relationships, and we both knew somehow that this was a date though it was never called a date. And we had a perfectly good time: Good food, good conversation, good drinks. She drove.

When it came time to go home, she drove me to the urban neighborhood I lived in and parked on the street near my house. As we were saying our good-byes, she enigmatically unhooked her seat belt. I wondered why. Then, I discovered that she wanted the freedom of movement to lean across the console and give me a kiss. It was a good kiss. It was actually a series of good kisses, and it went on for a while.

And suddenly, there was a loud rapping on the window of the car. We stopped kissing and that’s when we noticed that we had steamed up the windows a bit. So I cracked the window on which the rapping had occurred and there was a policeman staring in with his flashlight.

Now, you have to understand, this is two adults in a car in the city, not teenagers at some remote lover’s lookout in the country side on prom night; this was in a neighborhood where the police never wander around on foot, and certainly never bother the local residents in this manner. Yet, there was the steamy window, the uniformed police officer, and the bright flashlight.

“What can I do for you, officer” I said, thinking, “what is this Joker doing?”

“Ah, sorry to bother you,” realizing he was shining the flashlight in my eyes, diverting it, “I was wondering if you saw anyone coming by here. We’re in pursuit of a burglar.”

I listened for a moment.

“I don’t hear the dog,” I said. “There is no way anyone has been by here, but if I see someone, I’ll call.”

It is said that you never forget your first kiss. I think I might have. But THAT kiss, I will never forget not only because it was a very warm expression of closeness with someone I love and all that stuff, but because of the over the top comic relief associated with it. I mean really: A cop, a flashlight, a rap on the window???? GMAB!

Anyway, that is one of my favorite personal kiss stories. The Science of Kissing: What Our Lips Are Telling Us, a new book by Sheril Kirshenbaum has a bunch more about kissing, and is a must read for anyone who wants to try out kissing (you may like it) and keep it scientific.

You would think that kissing is pretty basic. A few different animals seem to do it, and we’ve all seen the pictures of chimps kissing. So, humans have always kissed, and it’s a basic feature of our species and we all do it and it’s kind of wet and messy and what else can you really say about it? But if that is what you are thinking, then you need to do two things: a) get more curious and b) remove your Occidento-normative Western Unthinking Cap and learn yourself some perspective.

Kissing is almost a human universal, but not quite. Not all cultures do this. The history of kissing is complex and interesting, to the extent that we know about it. Kissing may or may not be a signal for quality or ability in relation to other activities such as sex. Men and women seem to “use” kissing for different purposes. Science has something to say about the efficacy of lip-enhancing behaviors such as gloss and colorizing. And did you know that men and women do not necessarily like the same kind of kissing, at least in some contexts?

Sheril’s book is a fun read and there is no way you will not find it informative. Gender issues and sexuality is an interest of mine (as an evolutionary biologist) so I know a lot of this stuff, but I learned a great deal reading her book. And, it made me think.

To me, the most interesting take-home message from Sheril’s book is that kissing is both a fundamental, primordial form of communication involving the deepest limbic and visceral functions and the most basic social negotiations foundational to human existence, and something that any one group of human can simply do entirely without. Sheril documents the heterogeneous nature of kissing historically (and by inference prehistorically) and ethnographically, while at the same time demonstrating the nature and mechanics of kissing as an ethological factor in the kind of social space where one might also find cringing or punching or swearing or yelling or fearing or other visceral activities.

At first, this seems highly enigmatic, but need not be so. What is needed is to draw kissing down to some of it’s more basic components. What is kissing made up of that could be done some other way that does not add up to actual kissing?

Bodily closeness, face-to-face closeness, exchange of scent and sebaceous substances and possibly more bodily fluids, and so on … some subset of what any Middle Schooler would call “Totally eeww factor” … is probably found in every human culture, much like fried bread is found in every culture.¹ There is this list of things humans may do to/with each other in the process of negotiating (or at least playing around with) sex, marriage, or some other reproductive activity or social contract, and one way to piece this all together is with the Inuit muzzle rub, or some other activity, or a kiss.

It is also interesting that the kiss has spread over recent time. I wonder if it was very common at times in the past, fell out of favor, and returned, over and over. I am not necessarily being ridiculous when I imagine that the various behavioral accouterments of closeness would be combined, recombined, spread, forgotten, preferred, prohibited, in a kind of Dawkinsonian River Out of Eden: A Darwinian View of Life

I recommend the book. I suggest you consider it as a gift for your mate on his or her birthday. Or, to your mate as a Valentine’s Day gift! Since Amanda was born on Valentine’s day, I get to do both at the same time!

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¹Not really. Fried bread is not really found in every culture. See: Every Culture Has a …