Understanding the nature of children's attention to television helps to clarify the fundamental nature of television viewing and its effect on children. As a practical matter, understanding when and how children pay attention to television has been useful in designing television programs for children (e.g., Blue's Clues and Sesame Street).

The term "attention" refers to selective perceptual and cognitive activities that are directed toward a restricted portion of a person's environment. Brain research shows that when a person pays attention to an object in the environment, brain activation associated with perception of that object is enhanced, whereas brain activation associated with perception of other objects in the environment is suppressed.

There is no direct way to measure attention to television; rather, attention must be inferred from behavior or from physiological measures. The indicator of attention to television...