The Library


2 Min Read

Have you heard of osculation? No? Perhaps you’re familiar with kissing?

Actually, the two words mean the same thing: Osculation is the scientific word for kissing. And there’s a lot of science at play when it comes to kissing, from why we do it to what constitutes a good kiss.

Why kiss at all?

Kissing has become so normalized — and in many ways, romanticized — in mainstream western culture that the question “why kiss?” isn’t something you probably ask yourself often. However, when you stop to think about it, the concept of kissing is pretty strange, and even potentially unhygienic.

The answer may lie in evolutionary biology. Scientists believe that women kiss to pick up information: male saliva contains testosterone, and higher levels can increase a female partner’s sex drive, John and Julia Gottman note in their book, “The Man's Guide to Women: Scientifically Proven Secrets from the ‘Love Lab’ About What Women Really Want.

Men, on the other hand, use kissing more as a seduction technique, sociologist Helen Fisher notes in “Why Him? Why Her?: How to Find and Keep Lasting Love.” There are tons of examples of some male animals performing “wooing” techniques, including dances, colorful displays, or shows of violence and dominance. Kissing might fall under that category — as weird as it may be to think of it in that way.

Researchers also posit that some men like wetter kisses because they can transmit more testosterone to their partner. (The Gottmans refer to heterosexual relationships in their research, but don’t let that stop you from consensually kissing whomever you want!)

From a scientific perspective, what is a "good kiss"? 

It’s easy to know what a good kiss feels like compared to a bad one. But is there an objective criteria?

The answer is yes, although it’s far from comprehensive. Scientists have found that the best kisses last six seconds or longer. That is approximately how long it takes for the hormone oxytocin to kick in. Why is the “love hormone” necessary? The Gottmans note it ultimately helps increase the level of intimacy you feel with a partner, and helps decrease feelings of fear and pre-kiss nervousness. In other words, it soothes any potential for rejection you may have felt before going in for the kiss.

Why does kissing feel so good? 

The answer lies mostly in the body’s hormonal response to a good kiss.

Kissing stimulates the body in many ways: The kisser’s pulse and blood pressure increases, similar to what happens during a good workout. At the same time, kissing causes a person’s pupils to dilate and their breath to deepen. Then come the warm, “fuzzy” feelings: oxytocin spikes, cortisol rises, and stress levels go way down, Fisher explains. These physiological responses lead people to feel secure and connected, all while deepening desire for their partner.

All in all, kissing is deeply ingrained in human biology, and clearly serves a multitude of functions. Best of all, kissing doesn’t even have to lead anywhere — it has benefits all on its own. To feel better connected to your partner, we’d recommend working some “osculation” into your daily routine.


  1. Fisher, Helen. Why Him? Why Her?: How to Find and Keep Lasting Love. Henry Holt and Company, 2009.
  2. Gottman, John, et al. The Man's Guide to Women: Scientifically Proven Secrets from the" love Lab" about what Women Really Want. Rodale, 2016.