What’s in a kiss? Nothing less than the very essence of what it is to be human

It is impossible to know when and why lip kissing began. Photograph: Adrianna Williams/Getty Images

Sheril Kirshenbaum
One of my favourite historical accounts of kissing comes from the 1864 book Savage Africa. The British explorer William Winwood Reade described falling in love with the beautiful daughter of an African king.

After pursuing her for many months, he dared to steal a kiss. Unfortunately things didn’t go so well. The girl, having never encountered this before, screamed before running away in tears. Only later did Reade find out that this princess had interpreted his kiss as an intention to eat her.

Not all people express love and adoration through their lips. In fact, new research published in American Anthropologist reports that only 46% of cultures kiss mouth-to-mouth as most of us would recognise a romantic kiss today.

The study contradicts previous anthropologists who claimed the behaviour was near universal. Still, while it’s clear we’re not all connecting this way, it’s important to consider how we define a kiss before jumping to any broad conclusions.

Charles Darwin, the father of evolutionary biology, described kissing in his 1872 book The Expression of the Emotions in Man and Animals. He made an important distinction between kissing with the lips and various “kissing-like behaviours”, noting that rubbing noses and other related practices often serve a similar purpose and might be a precursor to modern romantic mouth-to-mouth kissing.

Darwin’s list of “kissing-like behaviours” included a series of exchanges between individuals that focused on the use of the lips, face and sometimes other body parts. He grouped kisses with similar activities that included “the rubbing or patting of the arms, breasts, or stomachs” and even an instance of “one man striking his own face with the hands or feet of another”.
After collecting so many accounts of similar exchanges all over the world, Darwin assumed that they must reflect an instinctual desire to receive “pleasure from close contact with a beloved person”. He concluded that the drive for humans to “kiss” is innate and, by broadening the definition of kissing to include related behaviours, it can be considered truly universal.

Some anthropologists disagree, maintaining that the kiss is simply a cultural phenomenon – something we learn in our own communities or see in the media and copy. And, of course, a European-style kiss is certainly not a required intimate activity from a reproductive standpoint.

The anthropologist Donald Marshall memorably described the people living on the Pacific island of Mangaia as the most sexually active culture on record. Men spent their late teens and 20s having an average of 21 orgasms a week (more than 1,000 times a year) without a single mouth-to-mouth kiss before Europeans arrived. Clearly human beings do fine with or without locking lips.

However, after an exhaustive exploration of the scientific literature and research, I am convinced the kiss is a wonderful example of a human behaviour where “nature” complements “nurture”. We seem to have an inborn drive to connect with another individual this way, but the shape it takes is influenced by our cultural mores and social norms. Just as Darwin observed nearly 150 years ago, kissing-like behaviours appear to be part of our evolutionary heritage, but the way we express them at any given time and place is heavily influenced by what’s familiar in our own societies.

As the anthropologist Helen Fisher points out, even in societies in which kissing wasn’t done, people “patted, licked, rubbed, sucked, nipped, or blew on each other’s faces prior to copulation”.

The most unusual kissing-like custom I’ve come across was described by the anthropologist Bronisław Malinowski in 1929. Lovers in the Trobriand Islands near New Guinea would bite off one another’s eyelashes during intimacy and at orgasm. “I was never quite able to grasp either the mechanism or the sensuous value of this caress,” he wrote.

Unfortunately, many historical accounts of kissing behaviours assume European kissing had been a mark of “civilised” culture, while not using the lips implied people were “savages”, “primitive” or “barbaric”.

In 1898 the Danish scholar Christopher Nyrop wrote that kissing was unknown in Polynesia, Madagascar, and among some tribes in Africa. He described the European mouth kiss as “a way of salutation vastly superior to the one in vogue among those savage tribes who salute with the nose”. Similarly, in 1929, the anthropologist Ernest Crawley reported that lip kissing was not found in much of the world, outside the “higher civilisations” such as Europe and Greece. Fortunately, a century later, scientists now know better than to make these kind of racist assumptions about behaviours they do not understand.

So when and why did lip kissing begin? It’s impossible to know. And, in reality, locking lips is likely to have arisen and disappeared all over the world for a variety of social reasons, including the discouragement of female sexuality.

The first literary evidence for kissing dates back 3,500 years to India’s Vedic Sanskrit texts. No word exists for “kiss” but there’s a reference to lovers “setting mouth to mouth” and a man “drinking the moisture of the lips” of a slave woman. From there we can follow historical accounts of social kisses in ancient Greece by Homer and Herodotus to the avid and passionate kissing practices in the Roman empire. Over millennia, the behaviour flourished in some parts of the world and nearly disappeared elsewhere because of religious doctrine and, at times, disease.

Romantic kissing as we recognise it may not have been as common in the past, but it’s certainly only one means of expressing a universal sentiment. And, when you think about it, mouth-to-mouth kissing probably seemed very odd and unpleasant to many ancient peoples, especially before the advent of toothbrushes and mouthwash.

The European-style kiss was spread through globalisation by way of military conquests, the arrival of ships in new lands, and the works of writers including Shakespeare and Dickens. Today it’s a social expectation for many of us because we have inherited a legacy of kissing celebrated through art and literature and amplified over time.

By 2015, kisses continue to look different depending on where you are. In places such as Mexico, France, Spain, the Netherlands, Argentina, Belgium, Switzerland, Lebanon, Haiti and beyond, both genders greet each other with a kiss on the cheek one to three times to express warmth and respect. The number and direction can vary by country, community or individual.

Elsewhere, for example in Finland and Britain, a handshake or nod is more common. Many Germans save kisses for those they are closest to, while it’s a private matter in India, Bangladesh and Thailand. The Maori of New Zealand and the Canadian Inuits practise a kind of nuzzle-sniff. And in Japan and China public kissing was formerly taboo, but is now increasingly common among young people. All of these examples are generalisations, of course, but it’s clear that we can see tremendous differences in how people express themselves through kissing customs.

While we vary in language, skin tone and social mores, the kiss has become a kind of universal language. It takes many shapes and forms, but remains the single most humanising practice that we share. And when we define the kiss broadly as a means to connect with another individual in this big wide world, I’m with Darwin.

Sheril Kirshenbaum is an academic at the University of Texas, Austin, working to enhance the understanding of science and energy issues