If you've ever watched a toddler descend into hysterical giggles because you put a shoe on your head, you know that children have a profound, if somewhat baffling, sense of humor.
What an adult finds funny and what a three-year-old finds funny are separated by a vast cognitive canyon. Yet, tracking what makes a child laugh at different stages of their early life is like watching a live-action roadmap of their brain development.
Humor isn’t just about being silly; it requires immense cognitive and social leaps. Here is how a child’s sense of humor evolves from birth to age seven, and what those laughs tell us about their growing minds.
0-6 Months: The Pre-Humor Stage (Joy vs. Funny)
Infants smile and laugh as early as a few weeks old, but gelotologists (scientists who study laughter) don't consider this true humor yet.
At this stage, laughter is a physiological response to physical stimuli or a general expression of joy. They laugh when they are tickled, bounced, or when they see a familiar, beloved face. This is social bonding and sensory pleasure, not cognitive humor. They aren't "getting a joke"; they are just feeling good.
6-15 Months: Peek-a-Boo and "Object Permanence"
Around six to eight months, a monumental shift occurs. This is the era of the greatest game ever invented for a baby: Peek-a-Boo.
Why is hiding your face and revealing it suddenly hilarious? Because the child is developing object permanence—the understanding that objects continue to exist even when they cannot be seen.
To a newborn, when you cover your face, you cease to exist. To a 10-month-old, when you cover your face, they know you are still there. The humor comes from the incongruity of the expectation (you are hidden) and the sudden, safe resolution (you reappear!). The baby is laughing at their own successful prediction of the world.
During this stage, infants also begin to laugh at unexpected sounds or exaggerated facial expressions that break the normal patterns they are learning to recognize.
1.5 - 3 Years: Incongruity and the Absurd
This is the golden age of physical slapstick and conceptual absurdity for children. At this age, toddlers have spent their short lives painstakingly learning the "rules" of the world: shoes go on feet, dogs say woof, soup goes in a bowl.
Therefore, the funniest thing in the universe is breaking those rules.
If you put a bowl on your head and say "Woof," a two-year-old will likely find it hysterical. They are experiencing "incongruity humor." The joke relies entirely on their newfound cognitive mastery. They must know the rule (bowls are for food) to find the violation of the rule (bowl as a hat) funny. Their laughter is essentially them celebrating, "I know you're doing that wrong!"
3 - 5 Years: The Rise of Verbal Humor (and Toilet Talk)
As language skills explode, so does a child's comedic arsenal. This is when kids transition from purely physical humor to verbal humor.
- Puns and Wordplay (The beginnings): They start playing with sounds. Calling a "banana" a "fanana" might be the height of comedy because they recognize they are subverting the phonetic rules of the language.
- The Conceptual Absurd: "What if an elephant rode a bicycle?" They can now hold two conflicting abstract ideas in their head and find the clash amusing.
- Toilet Humor: This is unavoidable. Around age three to four, children begin toilet training and learning societal taboos. Because words like "poop" and "fart" elicit huge, often shocked reactions from adults, the child realizes these words hold immense power. Saying them and laughing is a safe way to test boundaries and exert control.
5 - 7 Years: Riddles, Rules, and Social Humor
By the time a child enters early elementary school, their humor begins to look much more like adult humor, though the execution can still be a bit... rough.
- The Knock-Knock Joke Phase: Five- and six-year-olds become obsessed with riddles and structured jokes. However, they often grasp the format of the joke before they understand the logic. It is common for a five-year-old to tell a joke like: "Knock knock. Who's there? Banana. Banana who? I threw a rock at a car! [Hysterical laughter]." They know jokes require a setup and a punchline, but they haven't quite mastered the semantic double-meaning required to make it actually funny.
- Social Humor: At this age, children start using humor for adult reasons: to make friends, to deflect embarrassment, or, unfortunately, to tease others. They are learning the social rules of humor—who it is okay to joke with, and what is considered mean versus funny.
Why We Should Encourage the Silliness
When a toddler laughs at a shoe on their head, or a six-year-old tells a nonsensical knock-knock joke, they aren't just being goofy. They are actively exercising their working memory, testing their understanding of societal rules, deploying empathy, and mastering language.
Humor is a profound sign of cognitive health and development. So, laugh at the terrible knock-knock jokes. It's the sound of a brain growing.