There’s a lot that can be conveyed in a handshake, a kiss, or a hug. Throughout history, such a greeting was used to signal friendship, finalize a business transaction, or indicate religious devotion. But touching strangers can also transmit other, less beneficial shared outcomes—like disease outbreaks.
As fears about COVID-19, or coronavirus, mount, France has warned its citizens to pause their famous cheek kisses, and across the world business deals are being sealed with an elbow bump. But with histories tracing back thousands of years, both greetings are likely too entrenched to be so easily halted.
A popular theory on the handshake’s origin is that it began as a gesture of peace. Grasping hands proved you were not holding a weapon—and shaking them was a way to ensure your partner had nothing hiding up their sleeve. Throughout the ancient world, the handshake appears on vases, gravestones, and stone slabs in scenes of weddings, gods making deals, young warriors departing for war, and the newly dead’s arrival to the afterlife. In the literary canon, it stretches to the Iliad and the Odyssey.
The handshake’s catchall utility, used in friendship, romance, and business alike, makes interpretation difficult. “The handshake continues to be a popular image today because we too see it as a complex and ambiguous motif,” writes art historian Glenys Davies in an analysis of its use in classical art.
In America, it’s likely that the handshake’s popularity was propelled by 18th century Quakers. In their efforts to eschew the hierarchy and social rank, they found the handshake a more democratic form of greeting to the then-common bow, curtsy, or hat doffing. “In their place, Friends put the practice of the handshake, extended to everyone regardless of station, as we do still,” writes historian Michael Zuckerman.
There may be a scientific explanation for its lasting power. In a 2015 study, researchers in Israel filmed handshakes between hundreds of strangers and found nearly a quarter of participants sniffed their hands afterwards. They theorized that a handshake may be unconsciously used to detect chemical signals, and possibly as a means of communication—just as other animals do by smelling each other.
The kiss-as-greeting has a similarly rich history. It was incorporated into early Christianity and used in religious ceremonies. “In his Epistle to the Romans, St. Paul instructed followers to ‘salute one another with a holy kiss,’” writes Andy Scott in the book One Kiss or Two: In Search of the Perfect Greeting. In the Middle Ages, a kiss was used as a sign of fidelity and to seal agreements like property transfers.
Today, a swift kiss on the cheek known in French as “la bise,” is a standard greeting in much of the world. The word may have originated with the Romans, who had different term for each type of kiss and called the polite version “basium.” In Paris, two kisses is common. In Provence expect three, and four is the norm in the Loire Valley. The cheek kiss also common in countries like Egypt, where three kisses is customary, Latin America, and the Philippines.
It’s thought that during the plague in the 14th century, la bise may have stopped and wasn’t revived again until 400 years later, after the French Revolution. In 2009, la bise was temporarily paused as swine flu became a concern. At the end of February the French Health Minister advised against it as the coronavirus cases increased. “The reduction in social contacts of a physical nature is advised,” he said. “That includes the practice of the bise.”
In her book Don’t Look, Don’t Touch, behavioral scientist Val Curtis of the London School of Hygiene and Tropical Medicine, says that one possible reason for the kiss and handshake as greeting is to signify that the other person is trusted enough to share germs with. Because of this, the practice can go in and out of style depending on public health concerns.
In a 1929 study, a nurse named Leila Given wrote an article in the American Journal of Nursing lamenting the loss of the last generation’s “finger-tipping and the high hand-shake” customs in favor of a handshake. She warned that hands “are agents of bacterial transfer” and cited early studies showing that a handshake could easily spread germs. In conclusion, she recommended that Americans adapt the Chinese custom at the time of shaking one’s own hands together when greeting a friend. “At least our bacteria would then stay at home,” she wrote.