We’ve all had a moment where we’ve missed sarcasm, which is usually more or less the exact moment we learn to hate sarcastic people. But it seems that understanding sarcasm is a lot of work for the human brain.
Neatorama has a quick breakdown of the scientific work surrounding sarcasm and the brain, and you’ve got to jump through a lot of mental hoops to get there. In one paper, researchers at the Rambam Medical Center found that first, the brain has to process language in the left hemisphere to figure out the literal meaning of the words you’ve just heard. Then, to grasp sarcasm, the frontal lobes and right hemisphere kick in, looking at the speaker’s intention and the context of the words. Then everything is run by the right ventromedial prefrontal cortex, which is — among other things — our built-in sarcasm detector. Of course, there’s complete and total scientific consensus on this, because scientists totally agree on everything.
So why did we, as a species, decide to start mocking each other? It turns out sarcasm is a workout for the brain and allows us to communicate more effectively in certain ways, like calling someone out for being a slob or acting like a jackass without being completely blunt about it. Interestingly, we tend to be the most sarcastic with two groups of people: Close friends and total strangers on the Internet. So essentially we’re sarcastic only to the people who we either know will get it or can’t hit us with a pipe wrench.
It’s also useful in spotting brain disease and damage; since so much of the brain goes into processing it, if people lose the ability to grasp sarcasm, they might actually have a problem. Although those are some wonderful friends those people have, who only notice potentially serious cognitive problems because they start missing sarcastic remarks.
In other words, sarcasm is a useful tool we’ve evolved to keep our brains limber, and to better communicate with each other. Just remember, when using it, that if somebody doesn’t get it, you should be concerned for their mental health. Because that’s totally what’s wrong with them.