In 2001, Dr. Richard Wiseman asked a question: what is the world’s funniest
joke? He got people to submit and rate jokes on his website, LaughLab. After
40,000 submissions and one million ratings, he got his answer. Are you ready for the world’s funniest
joke, as determined by science? Here it is. Two hunters are out in the woods when one of
them collapses. He doesn’t seem to be breathing and his eyes are glazed. The other guy whips out
his phone and calls the emergency services. He gasps: “My friend is dead! What can I do?” The
operator says: “Calm down, I can help. First, let’s make sure he’s dead.” There is a silence,
then a gunshot is heard. Back on the phone, the guy says: “Okay, now what?”
Now whether or not you thought that joke was funny, it raises some interesting scientific
questions. Why did so many people find it amusing? What makes a good joke? What is
humor? Why do we laugh at all? These are actually complicated questions,
and there are multiple hypotheses as to what humor is and why we laugh. Let’s spend a little time
exploring what exactly tickles our funny bone. One strategy for studying humor is to start
by finding out what exactly makes us laugh. Laughter is ubiquitous. A good estimate says
that we laugh about 17 times a day. It’s a pleasurable activity that makes us feel
good. We even have entire industries built around making us laugh. If you’ve ever gone
to a stand-up comedy show or watched a comedy movie, you’ve participated in these industries.
Biologically, laughter is a human universal that starts around 3.5 to 4 months of age.
It’s an automatic reaction to amusing stimuli, or tickling. Mechanistically, it’s a series of
staccato segments that are each about 1/15 of a second, separated by about 1/5 of a second.
Laughter is usually full of vowels as well: hence the familiar “ha-ha” or “ho-ho.”
What about the physiological or neural components behind laughing? When you laugh, 15 different
facial muscles contract. Your zygomaticus major, the main muscle responsible for lifting your upper
lip, is also stimulated. In your respiratory system, the larynx, or top of your windpipe, is
half-closed by the epiglottis, a flap of cartilage that usually covers your windpipe when swallowing
to keep you from choking. This half-closure makes air intake happen irregularly, making you gasp. In
extreme circumstances when you are laughing a lot, your tear ducts are also activated.
Research from Peter Derks tells us what happens in your brain when you laugh at a joke. First,
the left side of your cortex, the side that is generally responsible for language and speech,
analyzes the words and structure of the joke. Your frontal lobe then becomes very active. The
right hemisphere of your cortex will also show activity, presumably the intellectual analysis
required to “get” the joke. Brainwave activity then spreads to the sensory processing area of
the occipital lobe, the area in the back of the brain that processes visual signals. If
the motor cortex is stimulated, there will also be physical responses to the joke.
Laughter itself appears to come from a specific area of the brain. One study in
1998 traced it to a small, 2 cm by 2 cm area on the left superior frontal gyrus. In this study,
electrical stimulation was applied to 85 different sites on the brain of a girl who had serious
seizures in an effort to figure out where the seizures were coming from. When this small area
was stimulated, the girl consistently produced laughter and felt a sensation of merriment or
mirth. At the very least, this area of the brain is extremely important for laughter.
Finally, laughter also appears to be rewarding physiologically. It seems to be regulated by
the same reward-circuit that makes us feel good when we perform activities. Endorphins,
the same chemicals that can give you a “runner’s high” are also released during laughter. In fact,
there is an ounce of truth to the saying “laughter is the best medicine”. It reduces stress hormones,
decreases muscle tension, and increases positive immune markers. In diabetics, laughter can lead to
less of an increase in blood sugar after a meal. And of course, laughter is incompatible with many
chronic negative emotional states that are bad for one’s health, like anger and depression.
It’s hard to be angry and laugh at the same time. All of this explains mechanistically how we laugh.
But when do we laugh and why? Laughter seems to be a social and communicative activity.
We rarely laugh alone. In fact, people are 30 times more likely to laugh in a social
setting. Laughter may actually aid in social bonding, helping bring us closer together.
Dr. Robert Provine conducted years of naturalistic studies that provide evidence for this. He and
his research assistants went to malls and city sidewalks to record what happened just before
people laughed. Over 10 years they studied over 2,000 cases of naturally occurring laughter. What
did they find? First, women tend to laugh more than men, unless men are listening to a woman.
They also found that the talker laughs 50% more than the listener in a conversation. Most laughter
also doesn’t follow jokes, or any real attempt at humor. 90% of pre-laugh comments were things like,
“I’ll see you guys later,” “Are you sure?”, “I know!”, and “Does anyone have a rubber band?”
These comments are obviously not funny. This suggests that laughter can instead serve as
a way to create social bonds between people. But what about humor itself? Why are things
funny? We actually don’t know for sure. Psychologists are still trying to figure
out what aspects of a joke or situation make us laugh. We do, however, have various theories. One
theory is that humor is due to incongruity. We laugh when there is a disconnect between
what we expect and what actually happens. Punchlines from incongruent jokes force us
to reconsider or reframe something. Take this joke. Police were called to a daycare center,
where a three-year-old was resisting a rest. When we hear the beginning of the joke about police,
we don’t expect the punchline to be about a child not wanting to take a nap. But incongruity isn’t
the best explanation for humor, especially since there are many cases when incongruity doesn’t
cause laughter at all. Would you laugh if you got an F on a test when you thought you got an A? No,
because that isn’t funny, even though there is a disconnect between our expectations and reality.
Another possible explanation for humor is the theory of superiority. We laugh at earlier
versions of ourselves and the misfortunes of others because we think we are better
than them. This type of humor is usually used to ridicule others. Think back to your childhood,
playing on the playground or being in school. Did you ever laugh when someone dropped their
lunch or passed gas? Your laughter could be explained by the realization that you
are superior to that poor person. Here’s another example: It’s pretty funny if the
Queen of England farts because it goes against the regality and majesty we expect from her.
Psychologists Thomas Veatch and Peter McGraw propose yet another theory: humor arises from
a benign violation of an accepted rule or moral. Emphasis on benign here; jokes with
this type of humor only work if the violation is non-threatening. In this case, an ethical,
social, or physical norm has been violated, but the violation isn’t very offensive or upsetting.
This theory helps explain slapstick humor. We know that being hit in the head with a frying pan
causes brain damage. But when the Three Stooges do it, we laugh because we know it’s just cartoon
violence and the characters aren’t actually hurt. Humor could also just be the result of a release
of tension. The philosopher John Morreall suggested that laughter may have its
biological origins as a kind of shared expression of relief at the passing of danger. We laugh when
something builds up tension and then relieves it. Sigmund Freud would agree. In his view,
laugher lets people release pent-up “nervous energy.” This explains why we laugh at poop
jokes and jokes about sex. When we reach the punchline, we don’t have to keep suppressing
supposedly inappropriate emotions like desire or disgust. This energy is released as laughter.
Finally, we may be able to explain parts of humor in an evolutionary context. Laughter
and humor occur in every human society. While we’re the only species to give out loud guffaws
in response to a joke, some animals seem to make laughter-like sounds when they play. Rats,
for example, will chirp while they play in a way that resembles our giggles. When rats are tickled,
they also chirp and socially bond with their human tickler. And rats seem to like being tickled;
they actively seek more tickling. Non-human primates also seem to laugh. When chimps play,
tickle, and chase each other, they produce a sound similar to human laughter. The universality of
laughter even outside of humans suggests that it could play an evolutionary role. For instance,
laughter could be important for animals and for our ancestors in signaling when mock aggression
and play fights are just that, a form of play. If you’re laughing as you wrestle with someone,
you make it clear that you’re just playing and not actively trying to harm them.
Humor is complicated. Although we have a lot of theories about why we laugh,
we honestly don’t really know precisely what makes
things funny. But maybe we don’t have to. Maybe some jokes are best left unanalyzed.