Science of Kissing: What our Lips are Telling Us

Sheril Kirshenbaum, science journalist, asks a simple question: why do we kiss?  She finds lots of answers, and even more questions.

Did you know that the scientific word for smooching is osculation? It's derived from the Latin word osculum, defined as a "social or friendship kiss, or kiss out of respect."

Did you know that “kissing [i]s practiced by over 90 percent of cultures around the world”?

Did you realize that the chemical exchange of saliva and pheromones can help kissers subconsciously determine if this match is The One?

But why do we engage in this behaviour? There is no easy answer. Kissing is serious business. Okay, not too serious—Kirshenbaum’s truly scientific book is written with an abundantly affectionate humour.

To try to discern our reasons for kissing, Kirshenbaum looks at a variety of academic approaches; evolutionary biology, anthropology, neuroscience, classical history, and psychology. These approaches each have their turn, and some seem more plausible than others. Calling our lips a “genital echo” of the brightly coloured buttocks of the female bonobos, or defending Freud’s theory that kissing is a symptom of breast deprivation, both admittedly trip me up. But they are part of the fun to try to figure out our deep-lipped reasons for wanting to kiss each other.

It was Charles Darwin that brought it to our attention that not all cultures indulge in kissing. The “Malay-kiss” he described as follows:

“The women squatted with their faces upturned; my attendants stood leaning over them, laid the bridge of their noses at right angles over theirs and commenced rubbing. It lasted somewhat longer than a hearty handshake with us.”

Essentially, this exchange is in smelling instead of kissing. It’s very like the kunik, practiced by the Canadian Inuit and similar again to a custom practiced by the Maori, making an interesting Pacific triangle of sniffy influence.

For her neuroscience research, Kirshenbaum attempted to use magnetoencephalography (yes, really) or a MEG machine to scan the “brain on kissing”, but getting two people into said machine and having them kiss without moving proved to be an insurmountable challenge. Kirshenbaum then modified her approach but only to open new directions of questions that shift from the central “why?”

Kirshenbaum concedes that there’s more research to be done, and that for her, the fun in learning more has not diminished. Neither has it for the reader!  There’s a lot more to discover if you read the book, but I won't kiss ’n’ tell any more than I already have. Fewer vacillations and more osculation, I say!

Originally posted on the Nonfiction Book Club Blog