Updated

The amount of time children under 8 years old spend on mobile devices has more than tripled over the past four years — to nearly one hour a day, a new study has found.

The report by the nonprofit Common Sense also found that more American families subscribe to streaming video services like Netflix and Hulu than pay for cable TV.

According to the study, kids under 8 spend an average of 2 hours and 19 minutes each day engaged with so-called “screen media.” Of that time, 48 minutes per day is devoted to mobile devices, up from 15 minutes per day in 2013 and 5 minutes per day in 2011.

Overall, young children devote 35 percent of their “screen time” to mobile media, up from 4 percent in 2011.

By contrast, the study found television occupies 58 minutes of young kids’ attention per day, down 11 minutes from six years ago.

“Even though the overall time of screen media use is unchanged, the nature and experience of media use are different,” Dr. Jenny Radesky of the American Academy of Pediatrics wrote in an essay accompanying the study. “Mobile device use is more individual, immersive, and on-demand, and it influences interpersonal dynamics differently and can be harder to break ... away from.”

Common Sense said the study was designed to provide “reliable, independent data on children’s use of media and technology and the impact it has on their physical, emotional, social, and intellectual development.”