We shake hands when we meet someone because the gesture evolved as a quick, wordless way to communicate peaceful intentions, establish trust, and size each other up. What feels like a simple social reflex actually layers together thousands of years of history, deep-rooted biology, and powerful psychological signaling that still shapes how we judge one another within seconds.
It Started as a Peace Signal
The oldest explanation is the most intuitive: extending an open right hand proved you weren’t holding a weapon. In ancient and medieval societies, where a concealed blade could end a conversation permanently, offering your empty dominant hand was a deliberate act of vulnerability. Some historians believe the up-and-down pumping motion served an additional purpose, dislodging any knife or dagger hidden up a sleeve.
The gesture appears in ancient Greek art as early as the fifth century B.C., where it was called “dexiosis,” meaning a joining of right hands. It showed up most often on funerary monuments, symbolizing a permanent bond between family members, even across the boundary of death. By the end of that century it had become one of the most common motifs in Greek memorial sculpture, representing loyalty, farewell, and the continuity of relationships.
Quakers Turned It Into an Equalizer
For most of European history, greetings were anything but equal. Lower-ranked men bowed and removed their hats before social superiors, who responded with a gracious nod. Women curtsied to their “betters.” These conventions, sometimes called “hat honour,” dominated etiquette books well into the 1700s.
The Quakers rejected all of it. Emerging in Britain in 1656 after the upheaval of the Civil War, they refused on religious principle to bow or curtsey to anyone. Instead, every Friend, man or woman, greeted every other person with a handshake regardless of rank. While they didn’t invent the gesture (that was a common misconception even at the time), they were its most visible and persistent champions. Their insistence on handshaking with “all comers, whether high or low” helped popularize it across British society between 1700 and 1850, gradually replacing the old hierarchical rituals. The handshake became, in essence, a statement: you and I meet as equals.
Your Brain Is Doing More Than You Realize
A handshake isn’t just symbolic. It’s a genuine sensory exchange. A 2015 study from the Weizmann Institute of Science found that people subconsciously sniff their own hands after shaking hands with someone, and they do it in a remarkably specific pattern. After shaking hands with someone of the same gender, subjects increased sniffing of their right (shaking) hand by more than 100%. After shaking hands with someone of the opposite gender, they increased sniffing of their left (non-shaking) hand by more than 100%. When researchers secretly applied odors to participants’ hands, the sniffing patterns shifted accordingly, confirming the behavior was driven by smell.
This suggests handshaking may function partly as chemical communication, similar to how many animals sniff each other when they meet. You’re not conscious of doing it. Over half the participants in the study touched their nose with their hand at least once even before any greeting took place. The handshake simply amplifies and directs a behavior your body already performs automatically.
Touch Triggers a Hormonal Response
Physical contact between people releases oxytocin, a hormone closely tied to trust and social bonding. Research using brain imaging found that even a touch on the palm from another person activates brain regions involved in pleasant feelings and social connection. When the touch comes from someone familiar, the oxytocin response is higher and stress hormones drop. When it comes from a stranger, cortisol (a stress hormone) rises instead, and the oxytocin effect is smaller.
This means a handshake with someone you’ve never met isn’t going to flood you with bonding chemicals the way a hug from a close friend would. But it does initiate a neurochemical process. It gives both brains a data point: this person made physical contact, it was brief and controlled, and nothing bad happened. That tiny exchange can lower the barrier to trust just enough to get a conversation started on warmer footing.
People Judge You by Your Grip
The psychological impact of a handshake is measurable and fast. Research published in the Journal of Personality and Social Psychology found that a firm handshake correlated positively with extraversion and emotional expressiveness, and negatively with shyness and anxiety. Trained observers who shook hands with study participants formed impressions that aligned with those personality traits. For women specifically, a firm handshake was also linked to openness to experience, and the researchers concluded it may function as an especially effective form of self-promotion in professional settings.
In practical terms, this means the few seconds of a handshake carry disproportionate weight in how people perceive you. The general consensus for a professional handshake is 2 to 5 seconds, with one to three vertical pumps, enough time to say your name and hear theirs.
The Same Handshake Means Different Things Globally
What counts as a “good” handshake varies enormously by culture. In Japan, the traditional handshake is light with minimal eye contact, and gripping too hard or pumping vigorously is considered rude. In Nigeria, a handshake should be firm and can last a long time, sometimes continuing through the entire opening exchange of a conversation. Pulling your hand away too soon signals disrespect. In Middle Eastern countries, handshakes tend to be softer and may be held longer than Westerners expect, which is a sign of welcome rather than awkwardness. In many Muslim communities, cross-gender handshakes are avoided entirely. A woman greeting a Muslim man she doesn’t know can place her hand over her heart and say hello instead.
These differences reflect the same underlying principle playing out through different cultural filters: the handshake communicates respect, and what “respect” looks like depends on where you are.
Hygiene Changed the Calculus
Handshakes are also remarkably efficient at transferring bacteria. A study highlighted by Harvard Health found that a standard handshake transmits twice as many bacteria as a high five and ten times more than a fist bump. The reason is simple: a handshake involves more skin-to-skin surface area and longer contact time.
The COVID-19 pandemic made this concern impossible to ignore. A 2024 study of 152 hospital doctors found that before the pandemic, 94% greeted outpatients with a handshake. After the pandemic, that number collapsed to 23%. Among the 86% of doctors who changed their greeting habits, nearly three-quarters cited infection control as the reason. While handshakes have returned in many social and business settings, the pandemic created a lasting shift in how some people, particularly in healthcare, weigh the social benefits of a handshake against the biological costs.
Why the Ritual Persists
The handshake endures because it solves several problems at once in a single, brief gesture. It signals peaceful intent. It establishes a baseline of equality between two people. It provides real sensory information, both chemical and tactile, that your brain processes below conscious awareness. And it gives both parties an instant, mutual read on personality and confidence. No other greeting packs that much information into three seconds of contact.