When can kids tell that a mistake is a joke?
It’s related to when they can tell that you are lying. I knew that kids could start lying around two years old – or even 18 months. ("Is your diaper dirty?" – "No!") A new study shows that:
Toddlers as young as 19 months are able to distinguish jokes from mistakes
Before this, mistakes are just as funny as jokes. About 19 months they’ll start trying to correct the mistakes and only laugh at the jokes. And about 25 months they can start to realize you might be able to lie, and they can tell if you are making a mistake on purpose to be funny. "Oops – I put my shoe on my ear!"