Do Toddlers Understand Sarcasm? Yeah, Totally.

A “smooth move” is never smooth. And if you’re told to convey your sorrows to “someone who cares”, it’s safe to assume that you should not find a caring person to talk to. Indeed, sarcasm is such a crucial part of the English language that a handful of otherwise benign expressions have all but lost their non-sarcastic meanings.

But when, as children, did we become so darn sarcastic? When did we first discover that adults who responded to our obnoxious behavior with a measured “aren’t you special” actually meant that we were not special at all? And what happens in our brains when we’re firing off snark?

Scientists have been studying sarcasm for at least two decades. We now know that exposure to sarcasm enhances our abilities to solve problems—courtesy of a fascinating study involving a complaints department that discovered that volunteers were better at solving merchandising issues when patrons complained sarcastically. Subsequent studies have confirmed that being on the receiving end of a sarcastic jab sharpens our creative powers. Perhaps it prepares us for mental exercise. After we’ve used our problem-solving skills to suss out whether that “thanks so much” was sincere, our brains are primed to solve other puzzles.

As for why we dole out snark in the first place, John Haiman of Macalester College in Minnesota told Smithsonian Magazine back in 2011 that sarcasm is all about establishing dominance. “You’re distancing yourself, you’re making yourself superior,” he said. “If you’re sincere all the time, you seem naive.”

Indeed, misunderstanding sarcasm—or being incapable of producing it—are signs of traumatic brain injury and other neurological disabilities. One study found that victims of closed head injuries have a difficult time telling the difference between sincerity and snark. Another found that patients with lesions in their prefrontal or posterior cortexes lacked both empathy and an understanding of sarcasm, suggesting a link between putting yourself in someone else’s shoes and then running off with them while muttering sarcastic witticisms under your breath.

In healthy brains, however, sarcasm appears to develop between ages four and six, depending on the study (and, interestingly given some of the neurological studies, on the amount of empathy they exhibit). Five-year-olds have been shown to identify sarcasm in sardonic puppet shows, but it’s unclear whether they find snark funny or witty at such a tender age. “Sarcasm is something that we don’t ‘get’ until a certain point in our childhood stage of development,” Melanie Glenwright of the University of Manitoba, coauthor on one puppet study, said in a press statement. “Kids detect sarcasm at about age six, but don’t begin to see the intended humor until around age 10.”

“Younger kids think slapstick is funny, and plays on words,” she says. “But not sarcasm.”

Even as kids mature, studies suggest that they rely heavily on the pronunciation of a sarcastic line rather than context clues. For instance, the word “sure” takes its literal meaning only when there’s no tone attached to it. “Sure,” on the other hand, means “definitely not”. But even without a snide lilt, if I asked you whether you’d like to swallow a cactus and you responded “sure”, I’d probably use context clues to determine that your “sure” was sarcastic. Not so with third graders and even sixth graders who “appeared largely oblivious to contextually implied sarcasm,” according to the authors of a 1990 study on the subject. “Children initially depend more heavily on intonation than on context in recognizing sarcasm.”

Which means that when you give your preschooler, third grader, and teenager sarcastic approvals of their “nice work“, you’re really telling them three different things. Your teen will get the message and your third grader will try to read your tone. But your preschooler? He’ll be one proud kid.