It’s a question that has kept 13-year-olds awake at night for centuries: Which way should you lean when you’re going in for a kiss?
Thankfully, scientists have not ignored this pressing dilemma. To put it in the parlance of a paper published earlier this year:
To share a mouth-to-mouth kiss with a romantic partner is one of the most intimate forms of physical affection. Though this action tends to be performed intuitively, a decision must be made for which direction one should turn to kiss the recipient.
The researchers observed “a consistent lateral turning bias,” with the vast majority of people leaning right when going in for a romantic kiss. One study found that 80% of people lean right when kissing romantic partners.
But why? In their paper, psychology researchers from the University of Saskatchewan in Canada point to the theory that this habit could be learned in infancy, as babies tend to make more rightward head turns.
But there are some cultural variations, as studies show significantly more left turns for those for those who read languages from right to left, such as Hebrew and Arabic. (Beware, cross-border lovers.)
The researchers compared images of romantic kisses and parental kisses. All kisses featured lip-to-lip contact, and the researchers coded the turning direction for 529 images of parent-child kissing and 161 images of romantic kissing.
Consistent with earlier research, they found a right-turn bias among images of romantic kissing. However, there was a significant left-turn bias for parental kissing.
The researchers posit that the parental tendency could be linked to how parents cradle an infant, which predominantly uses the left arm. But they admit more research is needed to test this theory and figure out, once and for all, why we lean in certain directions for certain kisses.
For now, if you’re gathering courage for a romantic kiss and want to avoid any awkwardness, science has your back: It’s best to lean right.