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Sunday, November 26, 2017

What is humor?

After years of intensive research, science still has no idea why some jokes are funny and others aren't.


H ere are two typical jokes.

The French existentialist Jean-Paul Sartre was sitting in a cafe when a waitress approached him: “Can I get you something to drink, Monsieur Sartre?” Sartre replied, “Yes, I'd like a cup of coffee with sugar, but no cream.” The waitress walked off to fill the order. A few minutes later, the waitress returned and said, “I'm sorry, Monsieur Sartre, we are all out of cream. How about with no milk?”

Two gold fish are sitting in a tank. One gold fish looks at the other and says: “Hey man, how the hell do you drive this thing?”

In one episode of the old sitcom Get Smart, two agents decide to break into an enemy hideout from two different doors. The enemy agents hear them and open the doors. At that exact moment, the two agents rush through the open doors, pass each other, and run out the other door. The bad guys try to shoot them, but shoot each other instead.

The first joke is an example of a logical absurdity. The second is a play on words. The last one is classic slapstick: the brain is set up to expect a standard gun battle, but silliness ensues instead. But what do these three types of jokes have in common? Why were Monty Python skits so amusing, but comedians on our late-night TV channels so dull and predictable? Science has studied this burning question for centuries without finding a definitive answer.

Humor theory 101

Here's my theory about why things are funny:

The brain keeps a running narrative of what's happening in its environ­ment. It uses the same mechanism to follow the story of a joke. When a joke gets to the punch line, it abruptly changes the frame of reference of the narrative and the brain has to recalculate. A good joke forces the brain to revise its narrative of what happened earlier in the story. This causes a moment of disorientation that is interpreted as humor. Jokes change the frame of reference “Time flies like an arrow. Fruit flies like a banana.”
This classic joke tricks the listener into parsing the second sentence incorrectly. After realizing it doesn't make sense, you're forced to go back and re-calculate its meaning. This sort of mental processing is essential for a joke to be funny.

Chang, Ku, and Chen[1] studied humor using EEG, and found sex differences in how men and women processed the jokes. Being scientists, they didn't know any good jokes themselves, so they were forced to download examples from the Internet. Indeed, the Internet is a rich source of jokes like the following:

A neutron walks into a bar and asks how much for a beer. The bartender replies “For you, no charge.”

A photon checks into a hotel and is asked if he needs any help with his luggage. He says, “No, I'm traveling light.”

Either of these would be good as controls, but the authors selected this gem for their experiments:

I was at the customer-service desk, returning a pair of jeans that was too tight.
Was anything wrong with them? the clerk asked.
Yes, I said. They hurt my feelings.

The authors say there are two models of humor. Wyer and Collins's three-stage model[2] says humor has three stages: incongruity detection, incongruity resolution, and elaboration. Suls's incongruity theory[3] is that humor involves the resolution of incongruity. The thigh-slapper above is humorous, say Chang et al., because the brain detects incongruity between prediction and reality, and provides a physiological reward for resolving the incongruity by comprehending it. Thus, insight is the key to a good joke.

I'm skeptical. When Archimedes had his Eureka moment, or when Einstein had his insight about gravity being the deformation of the space-time continuum, did they keel over in paroxysms of laughter? We don't know for sure, but I suspect there is more to a joke than insight.

EEG of males and females listening to a joke
Electroencephalograms (EEGs) of people listening to jokes. Red=female joke. Pink=female no joke control. Blue=male joke. Green=male no joke control. Black line=[insert political adversary here]. (From Ref.[1]).

Chang et al. found differences in the EEG in how men and women processed jokes. The more men comprehended the jokes, the funnier they felt them to be. Conversely, the extent to which women felt that a joke is amusing had no connection to their understanding of them. They conclude:

Women recruited more mental resources to integrate cognitive and emotional components at this late stage. In contrast, men recruited more automated processes during the transition from the cognitive operations of the incongruity resolution stage to the emotional response of the humor elaboration stage.

The authors speculate that men have evolved to be joke creators, while women are passive joke recipients whose social role is to evaluate the male's attempts at being amusing in terms of his social skill and desirability as a mate.

Bekinschtein's theory

Here's an example of an amusing German joke:

A child is mute until he is five, to the extent that his parents wonder if he might be developmentally impaired. Then over dinner one night, quite suddenly, the boy says “This soup is tepid!“ in perfect High German. His astonished mother asks him why he has never spoken before. The boy shrugs and says, “Because until now everything has been satisfactory.”

Here again, we see how the listener is forced to re-evaluate the story in a new frame of reference. Tristan Bekinschtein et al. [5] noted that a funny situation requires awareness. They took the joke “Why don't cannibals eat clowns? Because they taste funny!” and compared it to a collection of jokes that they correctly deduced were not funny, despite containing semantic ambiguities like the clown joke. Examples:

What was the problem with the other coat? It was difficult to put on with the paint roller!

Why did Cleopatra bathe in milk? Because she couldn't find a cow tall enough for a shower!

Using this collection of devastating comedy gold (23 jokes in four categories: ambiguous vs unambiguous sentences × funny vs unfunny jokes), 18 volunteers verified to have good hearing, and an fMRI machine, these researchers concluded:

The left inferior temporal gyrus and left inferior frontal gyrus are involved in processing the semantic aspects of language comprehension, while a more widespread network that includes both of these regions and the temporoparietal junction bilaterally is involved in processing humorous verbal jokes when compared with matched nonhumorous material.

What this tells us, besides confirming the stereotype of the scientist as a somber, humorless fellow looking for the nature of humor by dissecting the brain, is that our understanding of how the brain perceives reality is still shockingly limited.

Yet they may have been on to something when they say “The cognitive processes underlying the resolution of verbal humor seem to be part of executive functions (set shifting, reestablishment of context)”, which they say involves the frontoparietal network.

The social status theory

I found this old but still amusing joke on the Internet:

Pat and Mike were walking through the graveyard one night on their way home, when they came across a tombstone that read: Here lies a politician and an honest man. “Faith now!” exclaimed Pat to Mike, “I wonder how they got the two of them in the one grave?”

It's sometimes claimed, from the abundance of jokes like this one (some of which are more amusing than others), that jokes are power-motivated and that humor arises from the listener receiving a reward from believing they've received an increase in relative social status. But this is not really true. Humor arises because the listener follows the story, but at the punch line the entire frame of reference changes. The motivation of the characters, or their inner nature, is revealed to have been something baser and unexpected the whole time, and the brain is forced to reconstruct the story with the new interpretation in mind.

Update Of course for this kind of joke to be funny, the new motivation has to be (a) plausible in the mind of the listener and (b) different from what's expected. So the punchline of the Pat & Mike joke above wouldn't be amusing if it suggested that the politician was actually a saint. Likewise it wouldn't be funny, at least to Mike, if the politician was Mike's brother.

A related category is the joke that's merely a way of ridiculing and belittling the other person. Much if not most political humor is of this variety. Example:

Maybe he should ease into this ... by running for a lower office first, like President of the Hair Club for Men.

We could be charitable and say that's an attempt at humor, but any laughter it evokes would be entirely fake. Objectively it's not funny because it's just a way of expressing hatred. Any laughter this type of joke evokes sounds forced and insincere.

That's also why hearing the joke a second time is rarely funny. If the change in the frame of reference is known in advance and expected, the brain has time to reconstruct the narrative, and the joke falls flat. Explaining the joke has the same effect. Maybe that's why it's been so hard to come up with a good theory. Humor may be like quantum mechanical phenomena: as soon as you start to analyze it, it disappears.


1. Chang YT, Ku LC, Chen HC. (2017). Sex differences in humor processing: An event-related potential study. Brain Cogn. Nov 15. doi: 10.1016/j.bandc.2017.11.002. [Epub ahead of print] Abstract

2. Wyer, RS, Collins JE (1992). A theory of humor elicitation. Psychological Review, 99(4), 663–688.

3. Suls, J. M. (1972). A two-stage model for the appreciation of jokes and cartoons. In P. E. Goldstein, & J. H. McGhee (Eds.). The psychology of humour. Theoretical perspectives and empirical issues. New York: Academic Press, pp. 81–100.

4. Tian F, Hou Y, Zhu W, Dietrich A, Zhang Q, Yang W, Chen Q, Sun J, Jiang Q, Cao G. (2017). Getting the Joke: Insight during Humor Comprehension - Evidence from an fMRI Study. Front Psychol. Oct 18;8:1835. doi: 10.3389/fpsyg.2017.01835.

5. Bekinschtein TA, Davis MH, Rodd JM, Owen AM. (2011) Why clowns taste funny: the relationship between humor and semantic ambiguity. J Neurosci. Jun 29;31(26):9665–9671.


nov 26, 2017, 6:15 am; updated dec 03, 2017 6:43 pm

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