Why Do We Lean to the Right When We Kiss?

When you kiss someone, you probably try to match the way their head tilts to avoid an awkward moment. So does the rest of the world, according to a new study from the universities of Dhaka, Bath and Bath Spa in Bangladesh and England.

Most people lean to the right when kissing their partners, and there’s evidence that a preference to the right starts at birth — the scientists mentioned a study where newborn infants prefer to lie with their heads to the right instead of the left. In the new study, researchers included 48 married couples in Bangladesh.

Since public romantic kissing isn’t common in Bangladesh, the couples participated in the study by kissing in their own homes. They then separated, went into different rooms and reported on their experience.

The researchers were curious to know if sex and handedness (whether a person is left or right handed) influenced how the participants kissed. The data from the kissing couples suggested that a person’s handedness could predict how they were going to lean their head during a kiss.

How the initiator of the kiss leaned his/her head also influenced how the recipient would lean their head as well, suggesting that couples instinctively try to avoid discomfort. The data can explain most societal norms, the researchers wrote.

Related: Are Men With Beards More Attractive to Women?

“Societal learning or cultural norms can account for the findings reported here,” the researchers wrote. “In most traditional societies, males are expected to take on the more dominant role in sexual interactions while females are typically expected to be responsive to males’ desires and wait for them to initiate and orchestrate sexual activities.”

Bangladesh is a conservative Muslim society, where religious norms restrict females to be less sexually active and submissive compared to males. This aspect of the culture could be reflected in the study, the authors said.

Related: Holding Hands Reduces Pain, Syncs Lovers’ Heartbeats

The researchers said other influences on the study could include the way people in Bangladesh read from left to right as well as a majority of the population that is right handed. Michael Proulx, a Reader in the Psychology Department at the University of Bath, said the study provides insight into a culture that doesn’t display public affection.

“This study is unique in giving us a look into a private behaviour in a private culture, with implications for all people,” Proulx said. “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.”