And the more time spent using social media, the research suggests, the worse their academic performance.
"The implication of these results would seem to be that reducing college students' media use might improve their academic performance," said study lead author Jennifer Walsh, an assistant professor at the Miriam Hospital Centers for Behavioral and Preventive Medicine in Providence, R.I.
"However, given the central role media play in the lives of young people, this may not be a practical goal for educators and parents," Walsh added. Instead, she said, professors might try to integrate social media into their classrooms to remind students of assignments, suggest resources and connect them with classmates.
How the study was done
For the study, which was published in the journal Emerging Adulthood, researchers surveyed nearly 500 female freshmen at a university in the northeastern United States.
They were asked to recall how they spent their prior week in terms of 11 activities: watching television or movies; listening to music; surfing the Internet; social networking; texting; talking on the phone; reading magazines, newspapers or non-school-related books; and playing video games.
GPA results were collected in January and June. The women were also asked to grade their academic confidence and to note potential problems such as lack of sleep, use of drugs or alcohol, and failure to attend class or complete homework.
When the likelihood of multi-tasking was taken into account (using media while engaging in other non-media-related activities), the authors found the students were devoting nearly 12 hours a day on average to media-based activities.
And those with more media usage were more likely to report behaviors likely to hurt their academic performance. The exceptions: listening to music and reading newspapers were linked to higher grades.
Walsh said it's not possible to draw a direct cause-and-effect relationship between excessive technology use and poor academic performance. More research is needed to do that, she said.
One communications expert challenged the findings, calling them misleading.
Media time and multi-tasking
"It is absolutely not the case that college women spend nearly half their day using media," said Jeffrey Hall, an associate professor in the department of communication studies at the University of Kansas, in Lawrence. Previous research has found that almost 30% of media time involves multi-tasking - such as listening to music while texting, he said. If that figure were applied to this research, women would have spent closer to nine hours daily on media use. Hall called this "a more reasonable estimate."
Walsh said it's unknown whether the findings apply to male freshmen, given that this research focused solely on women.
"However, young women and men tend to spend approximately the same amount of time using media, and thus we might expect media to interfere with men's academic success in similar ways," she said.
Hall agreed. "There is no reason to believe that these results wouldn't apply to males, but there is also not research in this particular article to say that they would," he said. "We just don't know."
The research team's theories as to how cell phone use and social networking might be linked to worse academic performance do have merit, Hall added.
"Consider the fact that making priorities is very hard for students," he said. "And social networking is extremely compelling. Students feel that Facebook friends' comments on your status update can't wait, but class preparation can."
The other explanation, Hall said, "is that students who don't have the personalities that naturally lead them to be prepared for class are most vulnerable to the temptations of [social networking]. I think both are quite likely."
There is stronger evidence that cell phone use is directly and negatively associated with spring GPA than is social networking, Hall said.
"In some of my own research, students who talk on their cell phones more to close friends report feeling entrapped by the always-on nature of their mobile device," Hall said.
"They get the good part -- feeling close to and well connected to friends, a priority for young women especially," he said. "But [they get] the bad part too -- feeling trapped and guilty and unable to switch off."
The American Academy of Child & Adolescent Psychiatry has tips for parents about social networking and kids.