Schadenfreude, a German word for the joy derived from others' misfortunes, is probably something you've felt. It's that little smirk you get when an arrogant co-worker gets in trouble; or a beautiful celebrity gets a divorce; or when a millionaire non-fiction author is caught making stuff up. Keeping up the appearances of a sympathetic and nice person, you might outwardly grimace. But ultimately, you feel great. It's a childish thing to feel—literally.

A new study, entitled "There is no joy like malicious joy," found that human beings are ushered into this world of sinister happiness at the tender age of 24 months. Children feel schadenfreude, and they're not subtle about it, says Science News:

[T]oddlers don’t hide their feelings. The children showed happiness by doing anything from saying “good” to jumping up and down and clapping. Girls and boys behaved the same way.

To test whether or not kids can feel schadenfruede they had children listen to their mother read a story. In some cases, the mother held another child while she read, and her own child listened. Then mom spilled a glass of water on the book, interrupting her reading. When mom was cuddling another kid, the test children were delighted at their peers' misfortune. The test children, jealous about the mom's diverted affections, were happy when that diversion was interrupted by the spilt water.

It's not just a case of the terrible twos. Humans are born to be little green-eyed monsters. A 2008 study from researchers at York University found that when babies were purposefully excluded from a conversation they kicked, yelled and wiggled.

The researchers think that schadenfreude may have "evolved as a response to unfairness." (Though "[i]t’s hard to speculate," cautions Science News.) However it came to be part of our world, jealousy has a powerful grip on us. As the researchers explain in the new paper:

Human emotions are strongly shaped by the tendency to compare the relative state of oneself to others.

Indeed, jealous babies will grow up to be regular, jealous adults. Though somewhere along the line they'll learn to keep the jumping and clapping hidden inside themselves, like we all do.