The Three Stooges have, yet again, gotten themselves into a shenanigan that ended in exaggerated physical tumult and clumsiness. Everyone in the movie theater expected this, but the audience laughs anyway. On a screen at the other end of the building, people listen intently to the back-and-forth repartee of two witty love interests, laughing as they understand the innuendos and irony.

These situations may seem nothing alike at first glance, and yet they’ve both made people chuckle, and could both be considered comedic entertainment. Exactly what signals our brain to cause laughter, or even just to appreciate a clever joke, is yet to be understood. However, neuroscientists, psychologists, and comedians have all offered up some interesting theories on what sparks humor in the brain.

How To Measure Humor

Long before brain imaging technologies like MRI, psychologists and other scientists wondered what makes things funny, why we laugh, and why some people seem to have a better sense of humor than others. But where to begin? Many philosophers tried their hand at explaining laughter: Friedrich Nietsche said laughter was a reaction to existential loneliness, Freud supposed it was the release of pent up psychic energy. The problem, notes author and neuroscientist Dr. Scott Weems, is that there is no way to measure existential loneliness or psychic energy.

Even laughter, which provides a measurable consequence of humor, still does not provide a foolproof measure of humor itself — we’ve all appreciated a joke but not laughed, and everyone’s faked a giggle when they felt social pressure to do so. Without a concrete scale against which to measure comedy, scientists were left to logic it out.

“When the brain is given conflicting goals or information, it uses that conflict to generate novel solutions, sometimes producing ideas that have never been thought of before,” Weems writes in Ha!: The Science of When We Laugh and Why. “Humor succeeds because we take joy in this process, which is why a bored mind is a humorless mind.”

Ultimately, the way the mind processes incoming information and comes to conclusions can be blamed for humor. That’s obviously a broad process, but it was a start for many theories on the topic.

Theoretically Funny

There are several popular ideas about what humor is, and what causes it. We know none of them are totally accurate — after all, there is not a single joke that aligns with every theory, and no single joke everyone will find funny. However, these theories provided a springboard for scientists once we did develop the technology to take a look inside the brain and really see what was going on when a person laughed.

For example, the incongruity theory suggests humor rises out of contrast or surprise. When you hear the beginning of a joke, you’re anticipating where it’s going to go, even if you don’t realize you’re doing so. When what we logically expect is replaced by something else, our minds are forced to switch gears and adjust. Emotions — surprise, for one — come into play, and we experience incongruity between the concept of the joke (what we thought would happen) and the reality. We perceive this experience as humor.

Other popular ideas are more simple: Superiority theory traces back to ancient Greece and states that a person laughs at the misfortunes of others. Acting in a ridiculous manner capable of causing laughter is associated with self-ignorance, so anyone observing that person would laugh, feeling superior to them. Anyone who has watched a suspenseful movie will recognize relief theory — characters will crack jokes during intense scenes as comic relief, breaking psychological tension. Relief theory maintains that humor is a homeostatic mechanism, meant to ease anxiety caused by fear.

These theories are too simple to explain the intricacies of humor on their own, but when better technology came into the picture, scientists could see which parts of the ideas held water.


Humor can be a frustrating topic for scientists, particularly those studying hard sciences involving chemistry and biology. In an attempt to understand why we find some things funny, neuroscientists did what they do best — looked at the brain.

In 2001, York University psychology professor Dr. Vinod Goel conducted the first study using fMRI to explore humor. He imaged the brains of college students while they listened to two different types of jokes. One was a pun such as “Why did the golfer wear two sets of pants? He got a hole in one,” The other a more abstract joke along the lines of “What do engineers use for birth control? Their personalities.”

Goel noticed activation of the left interior prefrontal cortex, a brain area involved in phonological processing, when study participants heard the puns. These semantic jokes increased blood flow in the bilateral posterior temporal lobes — a brain region involved in language processing. Still, he didn’t actually know if the participants found those particular jokes funny or not. To see if there were any universal humor zones in the brain, he asked exactly this, then compared the jokes participants ranked as funny with the ones they thought fell flat. All of the funny jokes, whether phonetic or semantic, activated the medial ventral prefrontal cortex, a part of the brain’s reward system.

Following this research, more studies have not only suggested this same association between humor and the reward system, they’ve shed light on older theories as well. A 2004 study asked participants to watch episodes of Seinfeld and The Simpsons while hooked up to an fMRI machine. Researchers matched up the imaging readings with the shows’ laugh tracks, and were able to identify what was happening at the funniest moments, and in the moments right beforehand.

The researchers saw that in the miniscule moments leading up to laughter, when participants were just understanding the joke, their posterior temporal lobes, an area of the brain linked to resolution of incongruities, lit up. Once the participants were enjoying the joke and laughing, their amygdalas were more active, signaling another link between humor and the reward pathway.

Joseph Moran, the PhD student who led the Seinfeld experiment, said imaging research is beginning to point to parts of the brain used to understand and appreciate humor. But still, the results aren’t definite.

“These studies are still very exploratory,” he told the American Psychological Association. “So while the results broadly agree with each other, there’s no standard set of regions that we know are involved in humor, the way we know about Broca’s area and language.”

In other words, we still don’t get the joke.