The Science of Laughter

Laugh (verb): to make the spontaneous sounds and movements of the face and body that are the instinctive expressions of lively amusement and sometimes also of contempt or derision. 

We all have one. It’s unique to us, like a fingerprint. Some laughs are contagious. Some are frankly annoying. Some are quiet. Some are booming. Some people laugh at everything (I’m looking at you, Angie). For some, it’s like pulling teeth. What I love about laughter, though, is no matter what language you speak, we all can understand its sound.

Look at the definition again: “instinctive.” Humans laugh because sometimes, we can’t help it. It’s fun, sure, but it’s natural. We all have different senses of humor which leads to our brains deciding what warrants the act of laughter. And then sometimes you’re in the dentist chair, just having received nitrous oxide, and you think the wall’s paint color is hilarious. Anyway, moving on. 

WHY and, specifically, HOW, do we laugh? Let’s take a dive into the brain. There is not one specific area of the brain called “The Laugh Center.” Trust me, though, neurobiologists are ON IT. Many areas of the brain are both known to be and suspected to be involved in laughter. First you have to find something funny.  Then you have to actually make the sound of laughter with your vocal chords (larynx) and utilize air flow with the help of the diaphragm, and you have to move your facial muscles into a smile. Limbic system structures called the amygdala and the hippocampus, as well as the premotor and frontal cortex, and the brainstem are known to be involved. Lost in neurology jargon? OKAY. First your brain has to find something funny, then your body physically shows it. The brain is the control panel for all of it. Instinct leads to physical and outward reaction. Sometimes something is so funny, you feel like you achieved six pack abs in 30 seconds. If only it was that easy. 

The study of humor and laughter is called gelotology. Darwin (yes, Charles) even wrote about laughter in animals (primates particularly), suggesting that it functions to provide a cohesive survival advantage to the group. Laughter can literally save your life and advance a species, according to Chuck. We begin to show happiness physically with a smile within the first few weeks of life and normally begin to laugh around the fourth month. One twin study in particular showed that twins separated at birth (Daphne and Barbara, reunited at 40) due to adoption by two different sets of parents had a similar laugh and a similar sense of humor. This and many other twin studies suggest that humor, perception, and laughter is in one’s genetic code. Super neat.

You may not have known this, but laughter can also be a sign of neurologic damage, lesions in the brain, or presence of certain mental health disorders. We call this pathologic laughter. For example, gelastic epilepsy is a condition of seizures in which the main expression is laughter, rather than the classic sign of convulsions. The laughter seems mechanical and odd, but can at times be contagious to witnesses. Sufferers of this rare disorder have varying reports of how they feel during one of these seizures. Some feel a sense of exhilaration and sudden joy, while others feel no emotional connection to the laughter emerging from their mouths. Inappropriate laughter or laughter that seems particularly odd for the person showing it could be signs of either a tumor or an impending ischemic stroke. If the tumor lies in specific parts of the brain, neurons will act inappropriately and misfire, leading to uncharacteristic behavior shown by Uncle Billy Bob. When the brain suffers from lack of adequate blood flow to a specific region, neurons associated with this area can let off a sudden burst of signals (like a stress signal) leading to sudden uncontrollable laughter. AKA this person randomly and helplessly cracking up could be having a stroke in the next few minutes. People with specific kinds of strokes also have been found to exhibit pathologic laughter from the point they have the stroke and on, for the rest of their lives. Interestingly, pathologic laughter has been reported in 10% of folks with MS (with worsening episodes as the disease progresses) and in those with ALS. A four year, 1,145-person study in Europe found that in ALS patients, those with a sooner onset of emotional lability declined faster overall, with this lability considered to be an independent risk factor in disease progression (Barc et al, 2020). 

Now, back to good ole-fashioned laughter. To laugh, one must find something funny. We all have a different idea of what is laughable, and even what we find funny changes as we mature, learn, and experience life itself. For instance, there is great debate in the pop-culture universe as to whether or not “Seinfeld” or, my favorite sitcom of all time, “Friends,” is funny. Some people (and they’re wrong) just don’t see what’s amusing about these shows. Humorous events causes laughter, right? Okay, so what is humor? 

Humor evolves over time and within cultures. Jokes have contexts that are lost sometimes weeks to years after their inception. Original “slapstick humor” of the late 1800s was absolutely hilarious in its day, but a teenager now may stare blankly at the screen while watching the even more modern slap comedians, the Three Stooges. As you can imagine, several theories on humor exist. Even the dictionary blandly defines humor as “the quality of being amusing; a mood or state of mind.” Ok thanks, Webster; super helpful… When scientists attempt to define humor and understand its complexities, they kind of regret putting themselves up to the task. What people find humorous is constantly changing and is incredibly subjective. We all intuitively know what humor is, but only to us personally. Thus, designing studies on humor leaves lots of room for interpretation and criticism. Just what you want as a scientist devoting years of work to a theory: criticism. 

Anywho, in the 1980s, a few studies utilizing folks with various levels of brain damage and/or brain lesions found that the right hemisphere of the brain is important in perceiving that something is indeed funny. Then in 1999, Shammi and Stuss found that people with lesions in the right frontal lobe of the brain (behind and above your right eye) had the most trouble distinguishing between funny and boring cartoons, and also had trouble reacting appropriately. In studies of normal brains, other findings arose. For instance if you find puns enjoyable, your left temporal lobe (the brain tissue near your left ear) shows an increase in activity, evidenced by the brains of folks who listened to puns during a functional MRI. (Are you reading this, Dad? Your left temporal lobe game is strong.)  

Laughter is the best medicine. Where did this phrase come from, you may ask? If you find out let me know. But seriously, there is a well-known study conducted by UCLA biochemist Norman Cousins. Norman was diagnosed with a painful condition called ankylosing spondylitis in the 1960s. He was already studying human emotion and health measures, so he decided to use himself as a subject. He found that watching ten minutes of comedic shows leading to consistent laughter allowed him 2 hours of painless sleep. Laughter literally became his medicine (ok so maybe Norman coined the phrase? I don’t know.) Norman lived 25 years longer than his doctors predicted given his diagnosis. Twenty. Five. Laughter got him there. Humor and its medicinal effects go way back in documentation and written accounts. It’s even in Proverbs, y’all: “A cheerful heart is good medicine, but a crushed spirit dries up the bones,” (Proverbs 17:22). 

Laughter raises serotonin levels in the brain, which improves mood and relieves stress levels, even if it’s only for a minute. Recently, scientists have indicated that endorphins are indeed released in the brain when we laugh. In one particular study, test subjects allowed the research team to wrap their arms in a tightened blood pressure cuff. When all the test subjects were placed together in a room and allowed to laugh socially to clips of “Friends” and “Mr. Bean,” they could tolerate more pain from the arm cuff. When they were placed in a room alone, laughing solo only allowed them to tolerate slightly more pain than with no laughter at all. Moral of the study: social laughter raises endorphins, alters pain tolerance, and laughing together seems better than laughing alone. 

Now, keep in mind that we do laugh for reasons other than humorous jokes or movies. We laugh in social situations to break award silences, to act like we think our coworker’s story is hilarious (cue the fake “work laugh”), or we laugh along because everyone else is doing it. We can also laugh due to stimulation, like from tickling. Those with certain mental health conditions laugh derisively and with contempt, or they find things funny that aren’t considered socially normal. Regardless, laughter is a natural reaction to life situations that we’ve grown to find enjoyable. Laughter as a social construct began with our primal ancestors; it has evolved into a type of language tool, a way to relate to others, and a therapeutic regimen to endure life’s hardships. 

So what I’m saying is, laughter is important. Learn to laugh through life. I sound like a cliché canvas wall hanging from Bed, Bath, and Beyond. But seriously, learning to laugh through stress and find humor in your daily life will seriously pay off. Your quality of life will improve and your total body will benefit. 

References: 

Barc et al. Emotional Lability at Disease Onset Is an Independent Prognostic Factor of Faster Disease Progression in Amyotrophic Lateral Sclerosis. Aging and Disease. 2020 Oct 1; 11(5): 1021-1028. 

Sabato G. What’s So Funny? The Science of Why We Laugh. 2019 June 26. Retrieved from https://www.scientificamerican.com/article/whats-so-funny-the-science-of-why-we-laugh/. 

Savage B et al. Humor, Laughter, Learning, and Health: A Brief Review. 2017 July 5. Advances in Physiology Education: 41(3).  https://journals.physiology.org/doi/full/10.1152/advan.00030.2017?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org 

Welsh J. Why Laughter May Be The Best Pain Medicine. 2011 September 14. Retrieved from: https://www.scientificamerican.com/article/why-laughter-may-be-the-best-pain-medicine/. 

Wild et al. Neural correlates of laughter and humor. Brain, Volume 126, Issue 10, October 2003, Pages 2121–2138, https://academic.oup.com/brain/article/126/10/2121/314497