Attendance has been falling at America's National Parks since 1987. Blame videophilia, says a Nature Conservancy report. Videophilia is the love of electronic media. Those screens may be showing Internet, video games, movies or just plain TV. Young Americans are so glued to video that many rarely venture into the natural world outside. That troubles environmentalists, who see a growing estrangement from nature in high-tech societies. Funded by the National Science Foundation, the new study reported a similar trend in Japan and Spain. Of course, adults can be videophilic, too. I recall a recent splendid Sunday afternoon: Rather than skip into the golden sunlight, I stayed home to check e-mail and search for airfares to nowhere in particular. Then I watched a movie on TV. At least I knew what I was missing. That may not be the case for many of today's children, who have rarely experienced quality time with trees, rocks and frogs. Author Richard Louv sees this as a sickness and has a name for it: "nature deficit disorder." "Today, kids can tell you anything about the Amazon rain forest," Louv told me, "but not the last time they saw the leaves move." Contact with nature does wonders for children, according to the Center for Environmental Health. It helps ease attention-deficit disorder, aids cognitive development, enhances creativity and reduces stress. Louv thinks that video games shouldn't take all the rap for nature-deficit disorder. Parents don't encourage leisurely exploration of undeveloped landscapes. Some feel it wastes precious time. "They're afraid that if they don't get the kids in Suzuki violin lessons they won't get into Harvard," said Louv, who wrote a book on nature-poor upbringings, "Last Child in the Woods." Many parents also have a primal fear that a child in the wilds will be kidnapped or otherwise victimized by adults. Such cases are very rare, but the cable channels grab them and play the stories over and over - suggesting an epidemic of crime against children. As a result, Louv says, entire generations are being raised under "protective house arrest." Environmentalists worry that the loss of direct contact with the natural world will eventually weaken Americans' commitments to conservation and biodiversity. "Studies show almost to a person," Louv says, "that people with an environmental consciousness had a transcendent experience when they were kids." What do you mean by "nature"? I had to ask. Answer: Nature can be Yellowstone National Park, but also a clump of trees at the end of a cul-de-sac - an example of what ecologists call "nearby nature." To a biologist's eyes, the clump might not look like much, but to the child, it can seem a universe. Louv also faults the environmental movement for this turning away from nature. Preschoolers are handed books about recycling and see the environment as a joyless thing. For older students, constant talk about global warming and loss of habitat is programming kids to associate nature with Armageddon. Eventually, children should learn about the environmental threats, but first they must develop a firsthand love of nature. They have to simply go outdoors, listen to the wind, smell the wildflowers and look under rocks. Louv urges fearful parents to go with their kids into natural surroundings. (The experience reduces their stress, too.) And they should support the Scouts, nature centers and other organizations that help children get outside. Playing a National Geographic special on whales to the kids in the back seat does not constitute a complete environmental education. Parents should take the kids for a walk in a park. Nature-deficit disorder may be a growing malady but, fortunately, one that can be easily cured.