The Way We Kiss Is Programmed Into Our Brains

Researchers say the brain is hard-wired to ensure kisses go as smoothly as they possibly can. Emotions studio/Shutterstock

It wouldn’t seem that we put a whole lot of thought into how we kiss. After all, imagine if we agonized over every painstaking step of a single smooch.

BRAIN: Extend neck slowly. SLOOOOWLY. Raise chin. TOO MUCH! Purse lips. No, that’s too early. ABORT! ABORT!

Thankfully, as a new international study suggests, the whole process is mostly automated.

That moment — the outward flash of grace, and all the fluttery feelings that accompany it — may actually be the end result of an elaborate and cerebral ballet between the kisser and the kissed.

For one thing, according to the study published in Scientific Reports, our brains typically tell our heads to tilt to the right when leaning in. That goes for both parties, ensuring that, for the most part, mouths park comfortably where they should be. In fact, the study — an international collaboration between the universities of Dhaka, Bath and Bath Spa — found that two-thirds of kissers tilted to the right.

Furthermore, researchers noted that 79 percent of kisses involved men making the first move.

“We as humans make lots of behaviours while interacting with others everyday, but almost all the time, we are not aware of the biases we have in those behaviours, such as in turning the head to one side during lip kissing,” Rezaul Karim, lead author from the Department of Psychology at the University of Dhaka, noted in the study.

The first study of its kind

The research focused on 48 married couples, all living in Bangladesh, where public displays of affection are typically frowned upon. Each couple was asked to do the deed in private and then immediately spend some time apart to answer a series of questions.

“This is the first study to show sex differences in the initiation of kissing, with males more likely being the initiator, and also that the kiss initiators’ head-turning direction tends to modulate the headturning direction in the kiss recipients,” Karim said.

Researchers see the country as an ideal testing ground for the mechanics of kissing. Since the country censors the act from media, most residents don’t take their kissing cues from film and television. Instead, they're just doing what comes naturally.

“This study is unique in giving us a look into a private behavior in a private culture with implications for all people,” co-author Michael Proulx of the University of Bath noted in the study “Prior works could not rule out cultural learning due to having western samples. It turns out, we as humans are similar even if our social values differ.”

Handedness also played a pivotal part in the research results. If the person initiating the kiss was left-handed, their head would likely tilt in that direction. The person being kissed, regardless of handedness, responded by leaning their head to the left as well.

All of these tiny, seamless negotiations ensure that kisses don’t become collisions. If, for examples, partners mirrored each other’s head tilts instead, kissing would frequently end up in awkward fender-benders.

young couple kisses outside
The study found men are 15 times more likely to initiate kissing than women. Shutterstock

But the cerebral side of smooching leads to another question: Why does the brain favor the right tilt in the first place? Aside from handedness, the researchers suggest the mind splits tasks between hemispheres. When hormones like testosterone surge, it may create an imbalance on one particular side of the brain — and result in a tilt to the right.

Hormones have a way of throwing us off balance. And they likely wash over us in the single, sweet moment that we decide to lock lips with someone.

Thankfully, when it comes to kissing, they always seem to lead us in the right direction.