Holiday Calendar

National Let’s Laugh Day

Next celebratedFriday, March 19, 2027

Of the 1,200 everyday laughs Robert Provine recorded, only eight ever interrupted a phrase mid-sentence, and every one came from the person talking. March 19 is a nudge to laugh on purpose anyway.

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Last updated September 6, 2026 · by the Holiday Calendar TeamHave an update or spot an error?
YEARLY DATEMarch 19
OBSERVED INUnited States
CATEGORYHealth
SUBCATEGORYSelf-Care
ORIGIN

Community Origin

FOUNDING ENTITY
Not documented
FIRST OBSERVED
Not documented
HOW THE HOLIDAY CAME TO BE

What it leaves behind is promotion, not a founding.

National Let's Laugh Day surfaced on online holiday calendars by around 2017, and what it leaves behind is later promotion, including a Laffy Taffy sponsorship and seasonal news pickup. No founding individual, organisation, congressional record or presidential proclamation has been documented.

+ Know the story? Submit a founder Help us complete this holiday
INTRO

Most of your laughs have nothing to do with jokes

Think about the last time you laughed. There is a good chance no one had told a joke.

When psychologist Robert Provine and three students eavesdropped on 1,200 everyday laughs in shopping malls and on sidewalks, only 10 to 20 percent followed anything joke-like. Most laughter trailed flat little lines such as "Where have you been?" and "It was nice meeting you, too."

His conclusion was blunt: the trigger for laughter is usually another person, not a punchline. Laughter turns out to be a social signal we send to one another, closer to a handshake than to comedy. Provine even found that the person doing the talking laughs more than the people listening, which is the reverse of what you would expect if laughter were a reaction to someone else's wit.

That is the quiet premise of National Let's Laugh Day, an unofficial observance held every March 19 in the United States. It is a fun, low-stakes nudge to laugh on purpose, and a good excuse to look at what gelotology, the science of laughter, has actually figured out. (Do not confuse it with World Laughter Day, a separate international event on the first Sunday in May tied to the Laughter Yoga movement.)

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ORIGINS

Let’s Laugh Day history

INTRODUCTION

Laughter is one of the most studied human sounds that almost nobody set out to study. For most of the twentieth century it sat at the edge of psychology, dismissed as too frivolous for serious science. The day we now spend laughing on March 19 sits on top of decades of researchers who took the giggle seriously.

The puzzle they kept circling was simple to ask and hard to answer: if laughter is not really about jokes, then what is it for?

CHAPTER 01

A psychiatrist who drew his own blood

One of the first to chase it was Stanford professor William F. Fry, credited as a founder of gelotology, the study of laughter and its effects on the body. In the early 1960s, lacking volunteers, he experimented on himself, drawing his own blood at intervals while he watched Laurel and Hardy films. He named a field that the rest of science had been too embarrassed to claim.

CHAPTER 02

The eavesdropping years

Decades later, psychologist Robert Provine took the work out of the lab and onto the street. Rather than show people cartoons, he simply followed real conversations and wrote down who laughed and when. His sharpest finding was the "punctuation effect": laughter almost never interrupts the grammar of speech.

People say "You are going where? Ha-ha," not "You are going, ha-ha, where?" Across his recorded laughs, only eight ever broke a phrase mid-stream, and every one of those came from the speaker, not the listener.

CHAPTER 03

The animals that laugh too

The science then reached well past our own species. Once researchers started listening for laughter rather than for jokes, they began hearing it in tickled rats and playing apes, recordings that pushed the behavior's roots back far beyond anything human. Laughter, it turned out, was something much older and stranger than comedy.

CHAPTER 04

The day with no author

Against all that documented science, the holiday's own paper trail is almost blank. No founder, congressional record, or presidential proclamation has been found for National Let's Laugh Day; it simply surfaced on online calendars by around 2017.

Its most visible booster has been the candy brand Laffy Taffy, which has sponsored the day and prints a joke on every wrapper. The day is undocumented; the laughter it celebrates is anything but.

TIMELINE

Timeline

Fry names the field

Stanford professor William F. Fry runs self-experiments on laughter's physiology and helps found gelotology, the science of laughter.

Provine maps real laughter

Robert Provine publishes his analysis of 1,200 naturally occurring laughs, reporting the punctuation effect and that speakers laugh more than their audiences.

Rats are caught laughing

Jaak Panksepp and Jeff Burgdorf report that tickled juvenile rats emit the same roughly 50-kilohertz calls they make during play.

Laughter's family tree

Marina Davila-Ross's study of tickled great apes and human infants reconstructs a tree of laughter dating the behavior back 10 to 16 million years.

Laughter and the pain threshold

Robin Dunbar's group reports that genuine social laughter raised participants' pain tolerance, an effect they linked to endorphins.

A candy brand adopts the day

Laffy Taffy promotes National Let's Laugh Day as a sponsor, one of the observance's few documented real-world footprints.
This suggests that the critical stimulus for laughter is another person, not a joke.
Robert ProvinePsychologist and laughter researcher

WHY THIS DAY MATTERS

Why We Love National Let's Laugh Day

Bonding

Laughter is closer to a handshake than to a joke.

Because most laughter answers a person rather than a punchline, it works as a bonding signal that says we are at ease together. That is why a day set aside for laughing is really a day for connecting, and why laughing alone at a screen never quite lands the same way.

Body

Researchers keep finding measurable effects

In six experiments published in 2012, Robin Dunbar's group found that genuine social laughter raised people's pain threshold, which they read as a sign of endorphin release tied to social bonding. They measured pain tolerance as a proxy, not endorphins directly, so it is a research finding about a mechanism, not a prescription.

Ancient

It predates language itself

Tickle studies in apes and human babies trace laughter back through millions of years of primate evolution, long before our ancestors had words or jokes. A day that asks you to laugh is really asking you to use one of the oldest social tools we have.

BY THE NUMBERS

National Let's Laugh Day by the Numbers

1,200
Real laughs Provine observed in public
10 to 20%
Everyday laughs that follow a joke
~50%
More laughing by speakers than listeners
50 kHz
Frequency of a tickled rat's laugh
10 to 16M yrs
Estimated age of primate laughter

GOOD TO KNOW

Surprising facts about National Let's Laugh Day

Rats laugh, you just cannot hear it

Tickled by a researcher's hand, young rats emit roughly 50-kilohertz chirps that Jaak Panksepp argued may be a positive-emotion cousin of human laughter. The rats even chase the hand for more, though scientists still debate how far the laughter label should stretch.

The laugh is older than the human race

An acoustic study of tickled orangutans, gorillas, chimpanzees, bonobos and human infants drew a family tree of laughter that matches the apes' known genetics. It places the behavior 10 to 16 million years back, long before jokes existed.

A laugh is a whole-body workout

A real laugh sets off rhythmic contractions of the abdominal and breathing muscles, forcing the staccato 'ha-ha' and sharp exhalations while the heart rate climbs. That is why a hard laugh can leave you breathless and sore.

Your brain has a laugh detector

Provine described an 'auditory laugh detector,' a brain response tuned to the sound of laughter itself. It is why a laugh track or a giggling friend can set you off before you have any idea what is funny, and why laughter spreads through a room.

MYTH VS FACT

Common Misconceptions

The myth

We mostly laugh because something is funny.

The truth

When Provine logged real laughter in public, only 10 to 20 percent of it followed anything joke-like. Most answered ordinary conversation, which is why he called laughter a social signal more than a response to humor.

The myth

Science has proven laughter is the best medicine.

The truth

A 2023 review of 8 studies and 315 people found laughter sessions linked to about a 31.9 percent drop in the stress hormone cortisol, but rated the evidence only moderate to low and called for stronger trials. The benefits are promising, not settled.

The myth

National Let's Laugh Day and World Laughter Day are the same thing.

The truth

They are two different days. National Let's Laugh Day is a US observance on March 19 about laughter itself, while World Laughter Day is an international event on the first Sunday in May tied to the Laughter Yoga movement.

GET INVOLVED

How to Celebrate National Let's Laugh Day

EDITOR'S PICK

Call someone, do not text them

Provine's work suggests laughter is sparked by a person, not a line of comedy. A phone or video call gives the back-and-forth that real laughter feeds on far better than a screen full of memes.

WATCH

Watch comedy with other people

Shared laughter is the kind researchers find most powerful. Put on a stand-up special or a sitcom with friends or family rather than scrolling clips alone.

KEEP

Keep a one-day laugh log

Jot down the line that came right before each time you laughed. By bedtime you will have your own small version of Provine's experiment, and most entries will not be jokes.

READ

Read a Laffy Taffy wrapper aloud

The candy that has sponsored the day prints a corny joke on every wrapper. Reading one to a friend tends to earn a groan and a laugh in equal measure, which is rather the point.

LISTEN

Listen to an animal laugh

Recordings exist of rat chirps slowed down into something like a giggle, and of apes laughing when tickled. Playing one is a quick way to show that laughter is far older and stranger than comedy.

Test your knowledge

How well do you know National Let’s Laugh Day?

1 / 8

According to Robert Provine's research, roughly what share of everyday laughter follows something joke-like?

Answer

No. It is an informal observance with no congressional record or presidential proclamation. It is not a public holiday, and nothing closes for it.

COLOPHON

Sources

How we know what’s on this page. References, not endorsements.

8sources
4primary records
7independently dated
Primary records
Royal Society (Philosophical Transactions B)2022
Who's laughing? Play, tickling and ultrasonic vocalizations in rats
Peer-reviewed review of Jaak Panksepp and Jeff Burgdorf's work showing tickled rats emit roughly 50-kilohertz calls, proposed as a possible analog of human laughter, with the scientific debate over that interpretation.
View source
Current Biology (via PubMed Central)2009
The evolution of laughter in great apes and humans
Marina Davila-Ross and colleagues' acoustic and phylogenetic analysis of tickle-induced laughter in human infants and four great-ape species, dating laughter back 10 to 16 million years.
View source
Proceedings of the Royal Society B (via PubMed Central)2012
Social laughter is correlated with an elevated pain threshold
Robin Dunbar and colleagues' six experiments using pain threshold as a proxy for endorphin release, finding that genuine social laughter raised pain tolerance.
View source
PLOS One (via PubMed Central)2023
Laughter as medicine: a systematic review and meta-analysis of spontaneous laughter on cortisol levels
Systematic review pooling 8 studies and 315 participants that found about a 31.9 percent reduction in cortisol after laughter, while rating the overall evidence moderate to low.
View source
Additional coverage
Psychology Today2000-11
The Science of Laughter
Robert Provine's own account of observing 1,200 spontaneous laughs, finding only 10 to 20 percent followed jokes, that speakers laugh more than audiences, the punctuation effect, and the auditory laugh detector.
View source
Scientific American2006
A Healthy Laugh
Profile of gelotology and Stanford professor William F. Fry, a founder of the field, including his early-1960s self-experiments and the physiology of laughter.
View source
FOX6 Milwaukee
National Let's Laugh Day is a 24-hour joke fest celebrating the uniting force of laughter
Local news coverage of the March 19 observance and its sponsorship by the candy brand Laffy Taffy.
View source
AOL2024
It's no joke: March 19 is National Let's Laugh Day
Coverage confirming the March 19 date and stating that the origins of National Let's Laugh Day are unclear, with no congressional or proclamation record.
View source
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