American television viewers are increasingly finding that one screen won't do: almost all have a second-screen device and 87 percent use it while watching shows, a survey said Tuesday.

The NPD survey said multitasking consumers are splitting their attention between televisions and their laptops, tablets, smartphones, and other devices.

But most of these viewers are not interacting directly with the TV programs through games, voting or other activities.

The most common second-screen interaction was learning about actors in a show (29.8 percent) or seeking information about the program they were watching (23.1 percent), NPD found.

"Viewers are interested in searching to find further information about TV shows they are watching, but they are not using games and other immersive applications created as a component of the programming," said NPD's Russ Crupnick.

"This situation creates a potential diversion from advertising, and it will take a combined effort from content owners, advertisers, broadcasters, and others to present an aligned second-screen experience that will appeal to viewers."

The survey found PCs were the devices most used simultaneously with TV (60 percent), followed by smartphones (55 percent), and tablets (49 percent).

Just 19.4 percent said they shopped for a product seen on television, and 11.8 percent said they played a game related to a show.

Laptop users and consumers between the ages of 35 and 49 were most likely to shop for products via their second-screen devices.

"Converting viewers into impulse shoppers has big potential impact for advertisers, who can leverage second screens to further connect with consumers watching TV," Crupnick said.