Birth to 3 Months
What Your Baby Likes: Sensory stimulation, your smiling face, the comfort of routine.
What's Behind the Smiles: She feels a sense of security -- vital for her sense of well-being -- when you rock and cuddle her. At 2 months, she becomes more alert, just as her vision develops to the point where she can follow moving objects and people, so she'll love gazing at her surroundings.
What You Can Do: Hold her close and sing to her, suggests Catherine Grus, PhD, assistant professor of pediatrics at the University of Miami Mailman Center for Child Development. Babies love faces, so look directly at her as you talk about your day, the errands you're running, or who you might be seeing later on.


Around 2 months, she also might smile or coo happily at high-contrast primary colors and patterns placed within her view. Try hanging a simple mobile above her crib. She'll like the mobile's motion and bold patterns.

Even at this young age, babies will like imitation games. It starts with something she can already do, like form her mouth into an "O" or stick out her tongue. "You can try, when you're eye to eye, making an 'O' with your mouth and seeing if she does it. Then stick out your tongue and see if she does that too," suggests Judith Myers-Walls, an associate professor and extension specialist in the Child Development and Family Studies Department at Purdue University, in Lafayette, Indiana.

Make your daily routine fun for your baby by injecting a bit of silliness -- greet her with the same pet nickname when she wakes up, or sing the same song as you get her dressed, or playfully drip water onto her tummy during bathtime.

By 3 months, she may grasp, say, a rattle with your help, but she won't fully understand that she's the one shaking it.


3 to 6 Months
What Your Baby Likes: Different views of his world, being silly with Mom and Dad, kicking, batting his arms.
What's Behind the Smiles: He can now see greater distances and is beginning to understand what his little body is capable of, whether it's using his fingers to swat at a hanging toy on his bouncy seat or kicking his foot at his crib gym. "For the first time he's able to do things on his own, which is huge for him confidence-wise," says Gross. He'll like shaking, waving, and, yes, tasting, whatever he gets hold of.
What You Can Do: Allow him time on his back and tummy so he can see things from different perspectives. Offer safe objects of varying textures -- a plush stuffed animal, a bumpy rubber teething ring, a chunky board book -- for him to touch. Your baby will like roly-poly toys that wobble back and forth because he can knock them from side to side.


With your baby on his back, look him in the eyes and ask, "How big are you?" Gently stretch his arms over his head and say, "So big!" He'll like the repetition of this game and the sensation of your moving his arms in a way he can't yet do on his own, Myers-Walls says. Showing your baby his reflection in a mirror might also produce a smile or two -- possibly even a giggle -- because babies love seeing baby faces. He doesn't yet fully get that he's the baby in the mirror, Myers-Walls says, but he'll like that as he moves, so does the baby before him.

Just being plain silly sparks some serious smiles, Barbara Isaacs found when her daughter Kate was this age. "One of the first things that made her laugh was gently putting her belly on top of our heads, almost like a hat draped over us," says Isaacs, of Lexington, Kentucky. "She cracked up hysterically."

As you play with your baby, he'll like hearing from you, so reciprocate his happy sounds. "If your baby is making a cooing sound, coo back," Grus says. This back-and-forth exchange helps foster attachment between you and your baby, Myers-Walls explains.


6 to 9 Months
What Your Baby Likes: Seeing people he recognizes, interactive games, cause-and-effect toys.
What's Behind the Smiles: By 9 months, he's beginning to understand object permanence, the concept that an object or person still exists even after leaving his line of sight. He'll show you he understands this when he cranes his neck over his stationary activity center or high chair after a toy falls to the floor. He'll like it all the better if you pick up the toy for him to toss over the side again.


His memory is growing now, too, so what left him laughing yesterday -- hearing his sister sing a silly tune -- might make him chuckle days later when she does it again, Gross says.



What You Can Do: Initiate a game of peekaboo. He'll also like having you help him hide a stuffed animal or toy under a blanket and asking, "Where'd it go?"


Play a modified game of airplane with your baby by lying on your back, knees bent, and placing him on your shins. Make whooshing sounds as you gently "fly" him back and forth and side to side.

Toys that allow your baby to push a button and watch something pop up are sure to induce a smile. I remember adding voices to a pop-up toy featuring a farmer, cows, horses, and sheep. Emma would bust out laughing at my deep "Farmer Fred" voice.

Making dinner and need a distraction for your baby? Offer up a couple of pots and pans along with a wooden spoon. He'll like knowing he's capable of creating such a racket. Speak to him as you both "cook": "Mommy is making mashed potatoes for dinner tonight. What are you making? Looks like green beans! Stir 'em up!"


9 to 12 Months
What Your Baby Likes: Playing near Mom and Dad, performing for audiences (expect an encore if well-received!).
What's Behind the Smiles: She now realizes she can do quite a lot on her own, from playing with toys to picking up food on her plate and putting it into her mouth. She's sitting up on her own, possibly crawling, and maybe pulling up to a standing position. These milestones all give her a great feeling of accomplishment, though she might sometimes express frustration over what she wants to do but physically can't quite do yet, Gross says. She'll enjoy showing off, though, and will eat up the attention she's given.
What You Can Do: Encourage her emerging independence with lots of praise. For instance, when she's playing with a musical toy: "Look at you, pushing those buttons and making those sounds!" When you notice her pleasure at using a spoon just like Mommy and Daddy (even if she's not getting much food into her mouth), tell her, "You're eating all by yourself. What a big girl you are!"


Get physical with your baby: holding her securely in your arms, sing a song or silly chant you make up yourself, and turn in circles. She might also like for you to bounce her gently on your knee or dance with her to upbeat tunes.

Another idea: Try setting up a couch cushion obstacle course, Myers-Walls suggests. Place cushions on the floor and show your baby how to climb over and crawl from one to the other.


12 to 18 Months
What Your Baby Likes: Exploring, pretend play, imitating the "big" people.
What's Behind the Smiles: Life is good for your baby as he hits his stride with walking, possibly even running. He's exploring everything from the inside of his toy box and the contents of your kitchen cabinets to the leaves and insects in his backyard. He'll like doing favorite activities again and again. He also enjoys imitating what he sees. This might mean holding his play phone to his ear and chatting or giving a baby doll a bottle.
What You Can Do: Your baby is busier than ever, so give him safe places to explore. He'll love activities where he can make things happen, like running after and popping bubbles that you blow, or using toy musical instruments. Even simple everyday activities can have a fun twist: hold up his arms as you place a shirt over his head and ask, "Where's Billy?"


For his interest in pretend play, provide props such as plastic dishes and a blanket for an impromptu living room picnic. Reverse roles so that he gets to be the parent and you play the child -- you might let him pretend to put you to bed before he goes down, for example. Allow him to "help" you around the house by giving him a washcloth and spray bottle filled with water. Or place an old sock on his hand and let him help you dust. "It's an opportunity for him to feel good and make Mommy happy," Grus says.