Humor is a funny thing. We know it when we see it, but identifying why something is humorous is another thing entirely.
In fact, explaining why a joke is funny is a pretty reliable way to sap it of all humor.
Yet, psychologists have taken on a more ambitious task: the task of explaining what differentiates the humorous from the unhumorous — the funny from the not-so-much.
In a paper published last month in the Journal of Personality and Social Psychology, psychologists Caleb Warren and Peter McGraw find support for what they call the "benign violation" theory of humor. According to this theory, humorous events share two critical characteristics: They involve a violation (something that seems threatening, wrong or negative), but the violation is experienced as benign (inconsequential or good, such that there's nothing to worry about).
As an informal test and illustration, consider how the theory fares in explaining the world's funniest YouTube videos. With more than 2 million views, here's one candidate:
The video illustrates a violation in that the lizard jump is a deviation from the script and a potential threat. But at the same time, we can appreciate that it's benign: The attacking reptile is a harmless lizard, not a snake, and no real harm occurs. According to the theory, it's this combination of features that leads to humor. Without the violation, the video would have been boring. And if the lizard attack had caused real harm, concern would have been a more appropriate response than laughter.
The benign violation theory contrasts with alternative approaches to humor — such as the "superiority theory" — and builds on a family of related approaches called incongruity theories. Other incongruity theories focus on surprise, atypicality or the juxtaposition of incompatible elements as the basis for humor. These theories run into problems, though, in explaining why some surprising or atypical events aren't funny. For example, an event that's surprisingly bad can be tragic rather than funny, while something atypically positive might be joyous without making you laugh. Warren and McGraw argue that the benign violation theory dominates these alternatives because it not only identifies conditions that are necessary for a joke or event to be humorous, but those that are typically sufficient, as well.
In their paper, Warren and McGraw report six studies with a total of over 1,200 participants (mostly undergraduate students), each designed to test the benign violation theory against one or more alternative theories. For instance, in their final experiment, the benign violation theory is tested against the idea that the crucial ingredient for humor is surprise.
In the experiment, participants were seated across from another person to complete a language exercise. The other person looked like another participant, but was, in fact, an actor hired for the study. Once participants began the language exercise, the actor tossed some candy at them, either without an explanation or after stating the following: "I'm sorry for interrupting, but in a few seconds I need to toss this candy at you." The experimenters recorded how participants responded (e.g., whether they laughed), and how humorous they found the episode after it was over.
If more surprising events are more humorous, then the unanticipated candy-toss should have been more humorous than the candy-toss that was explained in advance. On the other hand, if the crucial ingredient for humor isn't surprise, but a benign violation, then the explained candy-toss should have been more humorous (even though it was less surprising): It was still a violation — in the sense that it departed from expected or "good" behavior — but it was easier to experience as benign in light of the explanation.
And that's what the experimenters found: Participants expressed more humor when the candy-toss was explained in advance than when it came as a surprise.
The findings from other experiments also supported the benign violation theory over tested alternatives, though it's hard to imagine a single theory of humor successfully encompassing all cases — from slapstick to knock-knock jokes. And can the theory explain the funniest joke in the world? I'll leave that as an exercise for the reader.
Tania Lombrozo is a psychology professor at the University of California, Berkeley. She writes about psychology, cognitive science and philosophy, with occasional forays into parenting and veganism. You can keep up with more of what she is thinking on Twitter: @TaniaLombrozo