Now that your baby is sitting up more securely and may be starting to creep or crawl, she'll often initiate play and enjoy having more control over her environment. As her fine motor skills improve, she'll become more adept at grabbing, palming, and holding her toys. She may soon figure out how to clap hands and will love playing games to hone this newfound skill -- so now's the perfect time to introduce things like patty-cake. Continue playing games like peekaboo and hide-and-seek, too; they help your baby figure out the concept of object permanence (the idea that things exist even when you can't see them).
Your baby's vocab is also growing by leaps and bounds these days. Even though she's not gabbing just yet, she may start to recognize familiar words, so games built around language are ideal to play right now. Just be sure to keep it simple to prevent her from getting frustrated. For example, lay out objects around your baby that you know she'll recognize. Then ask, "Where's the brush, the spoon, the doggy?" Praise her lavishly when she gets it right.
Baby's also really into cause and effect at this stage. She'll love dropping, throwing, and banging just about anything, just to see what happens. Give your baby some plastic bowls or pots and pans, and she'll likely shriek with delight at the sounds she can make. Mirrors may also become more interesting to your baby as she discovers her own reflection and how it imitates her movements (your baby may start babbling to the mirror -- so adorable).
These days, your baby sees everything in the house as a potential toy -- and for the first time, may have the skill to reach it, which means it's time to babyproof in earnest. Be sure to get all the wires, pet food, breakables, and poisonous items out of your baby's reach. --Jennifer Halpern, PhD
Originally published in the November 1999 issue of Parents magazine. Updated 2009.