The typical college student plays with his or her digital device an average of 11 times a day while in class, according to a new study by a University of Nebraska-Lincoln associate professor. More than 80 percent admit that their use of smart phones, tablets and laptops can interfere with their learning. More than a fourth say their grades suffer as a result.

Barney McCoy, an associate professor of broadcasting, embarked upon his study after launching his teaching career seven years ago and noticing the instructional challenges presented by students' digital devices.

From the front of his classroom on multimedia, he often saw the smart phones creeping out.

The view from the back of a classroom while a colleague taught Mass Media Principles was equally telling.

"They've got their laptops open, but they're not always taking notes," McCoy said. "Some might have two screens open -- Facebook and their notes."

Rather than rely on anecdotal（轶事的） evidence, McCoy decided to try to quantify how often college students tune out their instructors in favor of tweets and texts. During fall 2012, he surveyed 777 students at six universities in five states about their classroom use of digital devices for non-instructional purposes. He also asked the students how often they are distracted by others using digital devices and for their perspective on how digital devices should be policed.

"I don't think students necessarily think it's problematic," McCoy said. "They think it's part of their lives."

The students, from UNL and the University of Nebraska at Omaha in Nebraska, Morningside College in Iowa, the University of North Carolina, the University of Kansas and the University of Mississippi, were recruited for the computer survey by classroom instructors via email and personal contact. Respondents were not asked to reveal their name or institution, though colleges were identified through Internet Protocol addresses associated with the survey responses.

Here's how often respondents said they used their digital devices for non-classroom purposes during a typical day (percentages equal more than 100 percent because of rounding): 1 to 3 times per day: 35 percent 4 to 10 times per day: 27 percent 11 to 30 times per day: 16 percent More than 30 times per day: 15 percent Never: less than 8 percent. 

Nearly 86 percent said they were texting, 68 percent reported they were checking email, 66 percent said they using social networks, 38 percent said they were surfing the Web and 8 percent said they were playing a game.

McCoy said he was surprised by one response: 79 percent of the students said they used their digital device to check the time.

"That's a generational thing to me -- a lot of young people don't wear watches," he said.

The top advantages of using digital devices for non-class purposes, according to students, are staying connected (70 percent), fighting boredom (55 percent) and doing related classwork (49 percent). The most commonly cited disadvantages were that they don't pay attention (90 percent), miss instruction (80 percent), or get called out by their instructor (32 percent). More than a fourth said they lose grade points because of their digital habits.