From earliest infancy, play is the primary way children learn. Through play, children explore their bodies, their relationships with their parents and peers, and the world around them. An older baby who repeatedly drops a wooden block from his high chair is playing, but he's also an amateur researcher. How did the block sound hitting the floor? Is the sound the same on the carpet? Will mommy pick up the block? Will mommy frown or smile?

In addition to encouraging exploration and relationship development, play also helps children develop more subtle verbal and logical skills. Playing house, for example, reinforces the idea of the future tense and sequential thought, as the child says, "First I'll set the table, then we'll sit down to eat." Children's fantasy games let them explore new situations and model roles they have observed. If parents take an active part in their child's play, play can help build self-esteem. When a parent praises the stunning use of red in a toddler's picture or responds to a baby's cooing, kids learn that what they have to offer is interesting and entertaining to the larger world.