Between Ages 1 and 3
It's typically at this stage that kids start to comprehend the correct order of things, and the absurd or incongruous becomes funny: "Once babies figure out how the world is supposed to be, anything that turns the familiar on its head just a little -- Daddy pretending to drink from a bottle, Mommy trying to put on baby's shoes -- will get the laugh," notes Provine.
But once a child becomes more verbal, wordplay becomes fodder for comedy. I recently won belly laughs from my daughter's preschool classmates by replacing the predictable "duck, duck, goose" with "duck, duck, alligator."
Three-year-olds may start to get a few simple jokes, but by age 4, most kids will revel in knock-knock comedy or puns, and may even try cracking a few of their own. (Before this age, kids take everything completely literally!) While the punch lines may leave you scratching your head, laugh anyway. Be wary, however, of chuckling at any words or behaviors you would rather not hear or see repeated, warns Dr. Remer Altmann. "'Poopy head' jokes are par for the course with 3-year-olds -- and laughing at them will only provoke more." Her advice: "Ignore it; if something's not getting attention, they'll stop."