Do I Kiss You Right? Exploring Side Preferences in Kissing

When we kiss someone on the lips, we usually turn our heads either to the left side or to the right side in order to prevent bumping noses with our partner. Interestingly, the side to which we turn our heads is anything but random. Most people turn their heads to the same side every time they kiss.

Try to remember the last time you kissed someone: Did you turn your head to the left or the right side?

The chances are high that you always turn your head to that side when kissing. So the next time you kiss, try a little experiment: Instead of turning your head to the usual side, try turning it to your non-favored side. How does it feel? The experience is of course highly individual, but most people would say it felt “awkward," “weird,” or even “simply wrong.”

The head-turning preference during kissing has been investigated in a number of scientific studies. The first was a 2003 study from Germany, in which the researcher observed kissing couples in public places such as international airports, large railway stations, beaches, and parks in the United States, Germany, and Turkey (Güntürkün, 2003). The result? Most of us are right-kissers.

Overall, 64.5 percent of couples turned their heads to the right and 35.5 percent turned their heads to the left. This roughly 2:1 ratio was also observed in subsequent kissing studies in different cultures (Karim et al., 2017; Ocklenburg and Güntürkün, 2009; van der Kamp and Canal-Bruland, 2011).

Importantly, it takes two people to kiss. So what happens when two people want to kiss who have opposing head-turning preferences? It has been shown that social pressure can lead to an alignment of head-turning preferences during kissing in such situations. A French study (Chapelain et al., 2016) tested whether social pressure could affect the head-turning preference by observing kissing on the cheek as a greeting in 10 French cities. For their observations, the researchers chose locations where people frequently met and greeted each other such as entrances of university restaurants at lunchtime and the fountain of the main square in the evening. They observed more than 5,000 kisses with individuals using one to three kisses as a greeting.

The researchers found an interesting result: In each city, the large majority of individuals started to kiss on the same side – but this side was not the same for all cities. In seven cities — Montpellier, Toulouse, Aix en Provence, Rouen, Besançon, Strasbourg, and Lyon — people started with kissing the left cheek of the other person, turning their own head to the right. However, in three cities — Rennes, Lille, and Bordeaux — they started to kiss the right cheek, turning their own head to the left. This shows that people tend to align their kissing preference with the majority of the people with whom they interact, presumably to avoid awkward situations like nose bumping. While this has not been empirically investigated for romantic kisses between couples, it is conceivable that one partner might align their kissing preference based on social pressure to avoid awkward situations with a partner.

So why do we prefer to turn our heads to one side during kissing? The answer might be somewhat surprising, because the head-turning asymmetry during kissing is not the only one that we show. In fact, head-turning asymmetries can already be observed very early in life, right after birth. When a baby is placed on his or her mother’s belly, most show a consistent preference to turn their head to one side. In a recent study, it was shown that about 77 percent of babies have a right-turn preference, 18 percent have a left-turn preference, and 4 percent show no preference (Dunsirn et al., 2016). The head-turning preference during kissing might be an evolutionary remnant of this very early head-turning preference.

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