Now think about outdoor play. When a child plays outside, the pathway for each sense is strongly activated. Unlike indoors, the child sees and hears things very close by, mid-distance, and far away. Human brains are especially attuned to novelty, and the outdoors is filled with the unfamiliar -- with the weather changing minute-by-minute, animals passing by, plants responding to the seasons. We don't have to use our "indoor voices," so we can activate the neural pathway for shouting, and we can run farther and faster so we get to activate the pathways for exuberant physical play.

A moderate level of stress is also optimum for children's brains to develop. That may sound surprising, since most parents never want our children to ever feel any stress, but in fact, children thrive with a series of small challenges. Remember the old joke about the little boy who never talked: His parents take him to experts, nothing ever works, then one day when he's six years old he says, "Pass the salt." Everyone is amazed. "You can talk! How come you never talked before?" He answers, "Everything was fine up until now."

So we need frustrations -- but manageable ones -- so we can learn new skills and make new brain connections. Once again, play provides the single best way for children to experience these small surmountable obstacles.

Watch children at play, whether they are wildly racing down the beach or intently building a sand castle. When they are in their world -- the world of play -- they spontaneously create challenges for themselves, and then joyfully meet those challenges.