Here are some fun activities you can do with your baby to help develop his senses:

• One month: Place your face about a foot from your baby's face and move slowly from left to right, letting your baby's eyes track your movement.

• Two months: Purchase a wrist rattle. Put the rattle on your baby's hand and watch as he discovers the connection between his hand movements and the sound the bell or rattle makes.

• Two months: Say hello to your baby every time you enter a room. He'll recognize your voice and soon come to anticipate your arrival.

• Four months: Put a toy just out of your baby's reach — you may find that he can somehow wriggle or roll his way to it. (But don't make him crazy; hand it to him if he doesn't get it in fifteen seconds or so.)

• Five months: Whenever you're about to pick up your baby, hold out your hands and say “up.” Pretty soon, he'll be reaching toward you as soon as you say the word.

• Five months: Draw a picture of a simple smiling face on one side of a paper plate — and a mixed-up, Picasso-esque, face on the other. Hand your child the plate; he'll quickly figure out which side he prefers to look at.

• Six months: Drape a blanket or cloth diaper over a favorite toy, leaving a bit of the toy peeking out. Your baby will be thrilled when he “finds”

• his toy.

• Six months: If your baby is crawling confidently, make him an obstacle course of pillows and couch cushions to crawl over and around, always under adult supervision.

• Eight months: Let your baby watch you as you hide a toy under a blanket for him to find.

• Eight months: Show your baby how to put a lid on a pot. After he masters this puzzle, give him two lids and two pots.

• Nine months: Put several simple but distinct toys in front of your baby. Ask him to hand you one by name. “Give Mama the ball,” holding your hand out. You may be surprised that he gets it right.

• Ten months: Hand your baby a toy for each hand. Then hold out a third toy to him and see what he does. Will he try to somehow hold all three toys, or drop one of the two in order to pick up the third?

• Twelve months: If your baby is walking, give him a barefoot tour of different surfaces such as carpet, floor, grass, and sand.