ScienceOnly Human

What Makes a Pun Funny?

My name is Ginny and I’m an adult pun-lover. When I hear a good one — Photons have mass? I didn’t even know they were Catholic! — I don’t roll my eyes or smirk. I double over laughing, like a 7-year-old.

What is it exactly that makes a pun funny (at least to those of us who humbly accept the power of the pun)?

That’s the underlying question of a brain imaging study I came across last week. Its pretty pictures don’t answer the question, really, but they’re interesting all the same. And provocative: the data could have way-down-the-road relevance for communicating with people in vegetative states.

The researchers, led by Adrian Owen at the University of Western Ontario, focused on three types of jokes:

Regular joke: Why did Cleopatra bathe in milk? Because she couldn’t find a cow tall enough for a shower.

Funny pun: Why were the teacher’s eyes crossed? Because she couldn’t control her pupils.

Unfunny pun: What was the problem with the other coat? It was difficult to put on with the paint-roller.

The regular joke and the funny pun are both amusing, but for different reasons: in the decidedly unfunny parlance of humor theorists, the pun has “semantic ambiguity” and the joke does not. Part of the fun in the funny pun, in other words, is thinking through the two meanings of pupil.

But now compare the funny pun and the unfunny pun. Both have semantic ambiguity. So why is the funny one funny? The researchers say it’s because both meanings of the ambiguous word (pupil) are true at the same time, whereas in the unfunny pun, only one of the meanings of the ambiguous word (coat) is true.

Reading each joke produces a distinct cognitive experience, at least for me. So I’d guess that my brain is doing a different kind of processing for each. The study investigated this using a functional magnetic resonance imaging (fMRI) machine, which measures blood flow (and therefore, indirectly, neuron activity) in the brain. A dozen adult volunteers rolled on their backs into the scanner and listened to recordings of jokes and sentences read out loud as the machine recorded their brain activity.

Humor is complicated, apparently. Many, many areas of the brain light up more during jokes (regular or puns) than non-jokes, the study found. These include the amygdala, which processes emotions, the hypothalamus, which is responsible for a lot of automatic processes, like temperature and hormone control, and the ventral striatum, which is involved in the reward system. The jokes, as Neuroskeptic put it, “sent the brain into overdrive.”

But the most interesting data concerns a little-known brain region called the inferior frontal gyrus (IFG), a ridge on the bottom half of the frontal lobe. The left IFG lights up more during funny puns than regular jokes, and shows more activity during funny puns than unfunny puns, the study found. So this tiny little area, it seems, is the part of our brain that distinguishes between funny and unfunny, at least in these participants and for these kinds of jokes.

Of course, pinpointing the regions of the brain that process humor doesn’t tell us why we experience jokes as funny, as the researchers readily admit. But it could be useful for something far more important, in my opinion.

The reason I found the study, which was published back in June, is because I’ve been thinking a lot about what brain imaging can and cannot tell us. The lead investigator, Adrian Owen, made headlines several years ago for demonstrating an incredible application of fMRI: using brain activity to communicate with people whose active minds are trapped inside of inactive bodies.

In 2006, Owen reported in Science that when a woman in a vegetative state was put in a brain scanner and asked to think about playing tennis or walking around her house, these thoughts lit up predictable areas of her brain. Then last year, in the New England Journal of Medicine, Owen showed that a seemingly unconscious man could answer yes or no questions by mentally acting out the tennis scene for ‘yes’ or the house-walking for ‘no’.

In news stories about this research, the question that came up over and over again was whether a doctor could use this method to ask patients whether they wanted to be taken off life support. An ethical minefield, right?

In order for that to be permissible, you’d have to show (among many, many other things, I’d hope) that the person can not only answer relatively simple, objective questions, but can grapple with much more complex thinking, such as the consequences of their decision and their feelings about it.

That’s where the jokes come in: humor is not simple. If researchers could figure out a way to tap into various humor circuits with jokes, could they gauge the emotional capacity of an unconscious patient?

“That’s actually the sole reason for doing this study,” Owen told a reporter in July. “We need a way to try to access emotions in comatose and vegetative states.”

The study came out back in June, and of course Neuroskeptic was all over it. The post is worth reading: one of the study’s authors, Matthew Davis, left an interesting comment.

Photo depicts comedian Jessica Kirson, as captured by the inimitable Brian Friedmancartoon brain from Wikipedia

This post was originally published on The Last Word on Nothing