Kids who spend too much time staring at screens instead of imagining fanciful stories or playing with friends miss out on hands-on creative play, an essential part of a child's development, said Susan Linn, a psychologist and associate director of the media center at Boston's Judge Baker Children's Center.
"It's a problem because it means they're not exploring the world themselves," she said.
Publishers counter that digital books can attract kids to titles they otherwise might not see.
In any case, with the publishing industry weak, digital books are unlikely to go away because they are starting to generate revenue. With digital books, there are no shipping, printing or return costs -- which eat into profits. The sector is Random House's fastest growing, and the publishing behemoth recently announced that it was nearly doubling the number of digital books available. That will require a big investment, but Matt Shatz, vice president of Random House Digital, said it would pay off in the long run.
"The revenue opportunity that's available for publishers who make the effort is at a point where you can pretty easily justify the cost to convert the files," he said. "That hasn't been true until this year."
Langevin, of Houghton Mifflin, said that though digital books make up just 1% of sales currently, that could easily grow to 10% in five years.
That might grow even faster as teenagers and younger kids become more savvy with mobile devices. In Japan, for instance, fast mobile phone connections have helped feed a craze in which novels are written and read entirely on cellphones.
"There's a huge opportunity for publishers to use the growth of mobile devices to encourage young customers," said Carolyn Pittis, senior vice president of global marketing strategy and operations at HarperCollins Publishers. Already, Random House offers books such as "Curious George" and "The Way We Work" on the iPhone.
The digital format adds something to tactile books, said Mary Ann Sabia, vice president and associate publisher of Charlesbridge Publishing Inc. It's more interactive and gives children different insights into the story and characters, she said. Charlesbridge now has digital books that sing rhymes to kids and books accompanied by digital learning games.
Still, she said, "We don't think that print books are going to disappear."
If Thomas Knights is any indication, she's right. The 5-year-old from Jacksonville, Fla., likes to play games on Kidthing but doesn't like reading books on it, even though Dr. Seuss is one of his favorite authors.
"We looked at the Grinch one, but it doesn't do the voices as well as Mommy does," said Laura Knights, his mother. "He likes his mommy time."
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73% - Increase in sales of electronic books in October over the same month a year earlier
16% - Decline in sales of adult paperbacks in October from a year earlier
42 million - Sales of digital books in 2008, through October
$2.99 - Price of "100 Words to Make You Sound Smart" at Apple's App Store
Source: Assn. of American Publishers
Child-safe electronic books
So you want your kids to be bookworms, but you can't get them into books. Maybe they'll like the high-tech aspect of digital books. You could just sit them down at the computer and let them read the many children's books available online, but they might click on the wrong link and end up on an adult site. Here are some services that offer children's books away from the Internet, and a rundown on pricing.
Kidthing is a player, much like iTunes, that you download to your computer so that you can access content even when you're not connected to the Internet. The player is free, but you'll have to pay for many of the books and games available on it. Classics such as Don Freeman's "Corduroy" and Jerry Pallotta's "Icky Bug" books cost $5.99.
KINDLE, SONY READER
You're probably not going to want to get your kid his or her own Kindle, considering that the digital readers cost $359 and are currently on back order on Amazon.com. But you could get one for yourself and let your kid use it. You can get titles such as Kalli Dakos' "Don't Read This Book, Whatever You Do!" for $4.99 and "The Railway Children" by E. Nesbit for $2.50. The Reader costs a little less than the Kindle, but Sony charges more for the books: "Far-Flung Adventures: Hugo Pepper" costs $13.49, just 10% off the cover price.
It might feel weird to get your child an iPhone or an iPod Touch, but he or she would definitely be the cool kid in the schoolyard. Many of the books available on the iPhone are interactive, such as the 99-cent Bumblebee Touchbook, which lets your child touch any word to watch it move and hear it spoken, and "Buddy the Bus," a free e-book created for the iPhone that lets you record your voice and add it to the story.
Source: Times research