Research shows that children are spending half as much time outside as they did 20 years ago – and much more time doing "inside" activities.
Study: Juster, F. Thomas et al. (2004). "Changing Times of American Youth: 1981-2003", Institute for Social Research, University of Michigan. Child Development Supplement
The average American child spends 44 hours per week (more than 6 hours a day!) staring at some kind of electronic screen.
Study: Rideout, Victoria et al. (2005). Generation M: Media in the Lives of 8-18 Year-Olds. The Henry J. Kaiser Family Foundation.