While some time watching a favorite cartoon or interacting with a learning app isn’t harmful, excessive screen time as a replacement for real human interaction impedes brain development. Children have to be active in their learning experiences, including sensory, language, and physical activities, to be fully engrossed in learning (and growing). Creating limits on screen time also helps children understand limits in the world, and to explore that world in “real” life rather than through a screen —  let them try science exploration in real time, not watching them on a screen.