Due to the increased use of digital media, children's social skills may be declining.

Researchers from the University of California at Los Angeles found that sixth-graders who went five days without even glancing at a smartphone, television or other digital screen did substantially better at reading human emotions than sixth-graders from the same school who continued to spend hours each day looking at their electronic devices.

"Many people are looking at the benefits of digital media in education, and not many are looking at the costs," Patricia Greenfield, senior author of the study, said in a statement. "Decreased sensitivity to emotional cues -- losing the ability to understand the emotions of other people -- is one of the costs. The displacement of in-person social interaction by screen interaction seems to be reducing social skills."

For the study, researchers examined two sets of sixth-graders from a Southern California public school: 51 who lived together for five days at the Pali Institute, a nature and science camp about 70 miles east of Los Angeles, and 54 others from the same school. The camp doesn't allow students to use electronic devices -- a policy that many students found to be challenging for the first couple of days. Most adapted quickly, however, according to camp counselors.

At the beginning and end of the study, both groups of students were evaluated for their ability to recognize other people's emotions in photos and videos. The students were shown 48 pictures of faces that were happy, sad, angry or scared, and asked to identify their feelings.

They also watched videos of actors interacting with one another and were instructed to describe the characters' emotions. In one scene, students take a test and submit it to their teacher; one of the students is confident and excited, the other is anxious. In another scene, one student is saddened after being excluded from a conversation.

Researchers found that children who has been at the camp improved significantly over the five days in their ability to read facial emotions and other nonverbal cues to emotion, compared with the students who continued to use their media devices. The students who didn't attend the camp recorded a significantly smaller change.

"You can't learn nonverbal emotional cues from a screen in the way you can learn it from face-to-face communication," said lead author Yalda Uhls, a senior researcher with the UCLA's Children's Digital Media Center, Los Angeles. "If you're not practicing face-to-face communication, you could be losing important social skills."

The findings will be published in the October print edition of Computers in Human Behavior and is already published online.