How to Make a Baby Laugh

Few sounds and sights are more thrilling, wonderful, and joyful than a laughing baby. Moreover, getting the giggles is an important part of your child's development. Indeed, having a sense of humor plays a major role in building self-esteem, learning to problem solve, and honing social skills, explains Louis Franzini, Ph.D., author of Kids Who Laugh: How to Develop Your Child's Sense of Humor.

"It's one of the most desirable personality traits," says Dr. Franzini. "And parents can, without a doubt, help foster it." Happily, it's one skill you'll reinforce with pleasure. Here's how to make a baby laugh as they grow.

Making a 3-Month-Old Baby Laugh

Babies usually let out their first laugh around 3 or 4 months of age. But since kids this young don't understand humor, they giggle because of physical arousal (such as bouncing on your knee) or textural experiences. They may also laugh as a form of imitation.

What to do: Play a silly game (like pat-a-cake) and laugh up a storm.

Why it makes your baby laugh: Your little one is copying you. Special brain cells called mirror neurons hard-wire your newborn to imitate your actions, so they'll unconsciously return your smile and, in a few weeks, mimic your bursts of laughter. "It's like going to a comedy club," explains Gina Mireault, Ph.D., a professor of psychology at Johnson State University, in Vermont. "You laugh because everyone else is laughing."

But there's another reason this game never gets old: You aren't always this goofy. "A lot of humor in children is based on their realization that something is out of the ordinary or surprising, what we would call incongruous," says Doris Bergen, Ph.D., distinguished professor of educational psychology at Miami University, in Oxford, Ohio.

Making a 6-Month-Old Baby Laugh

Six-month-old babies have the capacity to let out hilarious belly laughs, and they'll giggle at experiences that are unfamiliar. Just make sure you're laughing and smiling along, too!

What to do: Pretend you're a monkey.

Why it makes your baby laugh: You may look extra silly, but you're having a good time. Clowning around, whether you're making slapstick body movements or funny facial expressions, is right up your 6-month-old's alley because it's just plain kooky.

The odder you act, the closer your baby will study you for emotional cues (a behavior called social referencing) to see that you're playing around. By smiling and laughing at yourself, you send signals that say "I'm having a ball" and encourage your baby to enjoy the absurdity.

"Parents need to give their infants cues to make clear, 'This is safe and this is fun.'" Dr. Mireault says. "Deadpan doesn't work with babies." Clowning around tends to be most successful when you dive into the fun of acting silly in an uninhibited way, suggests Dr. Mireault. So, let yourself go bananas. That dorky smile on your face will show your little one that you're trying to entertain them.

Making a 9-Month-Old Baby Laugh

As your baby's brain develops, they'll start recognizing things that are decidedly out of their ordinary realm of experience. Typically, they'll find these strange happenings funny.

What to do: Wear a shoe as a hat.

Why it makes your baby laugh: It's absurd. Your baby needs to perform some impressive mental gymnastics to comprehend this. They first have to know that shoes go on feet, not heads—a fact they've picked up in the past few months by watching the people around them.

In true baby fashion, anything that's funny once is funny five times in a row. "Parents forget this because it's so simple, but if there's something that makes your baby laugh, repeat it," says Lawrence J. Cohen, Ph.D., author of Playful Parenting. "We adults tend to get bored, but for a baby, everything is so new that it might still be funny 20 or 30 times."

Making a 12-Month-Old Baby Laugh

As babies get older, they rely less on watching adults in order to know what's funny; they begin to make the call on their own.

What to do: Get the cat to meow.

Why it makes your baby laugh: For babies this age, odd sounds are particularly hilarious, as evidenced by a few popular YouTube videos that show babies laughing hysterically as Dad makes strange, high-pitched pinging noises or tears a piece of paper. (Search YouTube for "laughing baby" if you need a pick-me-up.) Experts aren't sure why certain words and sounds are comedy gold, but hey, whatever works!

Making a 15-Month-Old Baby Laugh

Around 15 months, you'll notice a role reversal: Your baby tries to make you laugh!

What to do: Let your toddler tickle you.

Why it makes your baby laugh: "Babies seize on figuring out what people find funny," says Vasu Reddy, Ph.D., a professor of psychology at the University of Portsmouth, in England. "By the end of the first year, most kids are doing something to elicit laughter."

You may have noticed this around 7 or 8 months when your baby made a silly face over and over because it cracked you up. But by 15 months, some tots are really starting to work the room, and a tickle attack on you has the added fun of being a zany role reversal.

Making an 18-Month-Old Baby Laugh

At 18 months, your little one has the world (or at least their portion of it) largely figured out, so nothing is more hilarious than making a blunder intentionally, or pointing out when someone else makes one.

What to do: Make a mistake on purpose.

Why it makes your baby laugh: "When toddlers make a deliberate mistake—for instance, singing the wrong words for a song they know—they're demonstrating an awareness of cognitive incongruity," Dr. Bergen explains. The joke is that they know what's supposed to happen, but it doesn't, like when Mr. Noodle on Sesame Street uses a banana as a trumpet. With your kid's budding language skills, they just might tell you that a cow says "baa," or that the dog's name is Silly rather than Spot.