The Science Behind Kissing

The Science Behind Kissing

Let’s see what psychological research has to say about how people use kissing to build and maintain connections.

At its simplest, we can define kissing as when there is direct contact between one person’s lips and another person’s body (Floyd, 2006). Amongst romantic partners, this usually means contact between the lips of one partner and the lips of the other partner. Our lips are particularly sensitive body parts, full of nerve endings and touch receptors, and our lips activate a large part of the somatosensory cortex of the brain, suggesting that they are an especially important source of tactile (touch) information for our brains (Floyd, 2006). Therefore, it is unsurprising that romantic kissing is a powerful sensory and emotional experience for most of us, and that it often ends up involving other forms of romantic or sexual touch.

Why We Like Kissing

One theory as to why we like to kiss and continue to do so throughout our lives – apart from the pleasurable sensations associated with it – is that it may be a form of biological communication (Nicholson, 1984). When you kiss another person, whether on the lips or elsewhere on their bodies, you come into contact with their sebum, an oily substance secreted by our skin to help keep one’s hair and skin from drying out. Sebum may be a semiochemical – a chemical that delivers important information about the person you are kissing, such as the pheromones excreted by their body. Pheromones, whether sensed through kissing or by smell, are an important component of attachment and feelings of sexual attraction (Grammer et al., 2005).

It is through this sebum that we also may get valuable information about how complementary our immune systems are; parents having complementary immune systems should result in more resilient offspring (Wedekind et al., 1995), which may explain why people with complementary immune systems are more sexually attracted to each other. Of course, we are generally not conscious of this; instead, we just know that it felt good to kiss this person or that they smelled and tasted good to us.

“Never close your lips to those whom you have already opened your heart.”
― Charles Dickens

Kissing Functions

In romantic relationships, kissing seems to play an important function in both developing and maintaining a love connection (Wlodarski & Dunbar, 2013). Partners use kissing to demonstrate interest, build passion, and continue to show love and investment. People also kiss their partners to encourage their partners to behave in certain ways and to feel better about themselves (Thompson et al., 2019). In these ways, we can see that kissing between romantic partners is also a form of using the relationship to regulate oneself and the other person. For example, a kiss when both partners are finally home at the end of the workday can signal, “I’m here with you now – you are the focus of my attention.”

At the same time, as we noted above, kissing as a form of expressing affection and care is present in nearly every human culture (Eibl-Eibesfeldt, 1970). All the same motives we have already discussed can be present in non-romantic kissing, too. It is a fundamental component of how people who care about each other, whether friends or family, and in some cultures, it is a firmly established component of greetings, even between two people who are meeting for the first time (Chapelain et al., 2015).

Tips on Kissing

Believe it or not, there is very little scientific research on what makes a good kisser! So here are my therapist-thinking tips for being a good kisser:

1. Be curious about how you’re doing and open to feedback. You cannot read your partner’s mind, but you can learn about it by asking. Do they like what you’re doing? One good way to put it would be, “Is there anything I could do to make you like this even more?” It may not sound sexy, but it shows that you care and want to make the experience as pleasurable as possible for them.

2. Kiss when it feels right. Sometimes we give or receive kisses when we aren’t actually in the mood. Good kissing is consensual and contextual: it arises naturally out of a desire to connect, and it is not forced.

In Sum

It seems like scientific research has confirmed what we probably already knew: that kissing is a behavior that brings us together and keeps us close, one that is natural and pretty much universal. May we all have as much of this feel-good experience as we want!


● Chapelain, A., Pimbert, P., Aube, L., Perrocheau, O., Debunne, G., Bellido, A., & Blois-Heulin, C. (2015). Can population-level laterality stem from social pressures? Evidence from cheek kissing in humans. PloS One, 10(8), e0124477.

● Eibl-Eibesfeldt, I. (1970). Love and hate: On the natural history of behavior patterns. New York: Methuen.

● Floyd, K. (2006). Communicating affection: Interpersonal behavior and social context. Cambridge, England: Cambridge University Press.

● Grammer, K., Fink, B., & Neave, N. (2005). Human pheromones and sexual attraction. European Journal of Obstetrics & Gynecology and Reproductive Biology, 118(2), 135-142.

● Nicholson, B. (1984). Does kissing aid human bonding by semiochemical addiction? British Journal of Dermatology, 111, 623–627.

● Thompson, A. E., Anisimowicz, Y., & Kulibert, D. (2019). A kiss is worth a thousand words: The development and validation of a scale measuring motives for romantic kissing. Sexual and Relationship Therapy, 34(1), 54-74.

● Wedekind, C., Seebeck, T., Bettens, F., & Paepke, A. J. (1995). MHC-dependent mate preferences in humans. Proceedings: Biological Sciences, 260, 245–249.

● Wlodarski, R., & Dunbar, R. I. M. (2013). Examining the possible functions of kissing in romantic relationships. Archives of Sexual Behavior, 42, 1415–1423