Social-media denizens, a common criticism goes, are cocooned in silos of homogeneous individuals, cut off from real-world relationships and apathetic about real-world concerns such as voting. But a new study of adult social-media users found just the opposite.

Results of the survey show that Facebook users are more trusting, have more close friends, get more support from those friends and are more politically engaged than people who do not use the social network, the Pew Research Center's Internet & American Life Project said in its June report.

"Across the board, we see there is no negative effect" from social-media use, project director Lee Rainie said. "In fact, there are a host of positive outcomes that challenged some of the worst suspicions that people have about the impact of social-network sites."

Pew said the survey is the first nationwide, representative look at the impact of social networking sites on users' social and civic connections.

One of the survey's findings is that only 3 percent of respondents' Facebook friends were people they have never met in person, and 7 percent were people they met just once. A much larger share are people they know from high school or college, or are relatives or co-workers.

"These are real friends," said Keith Hampton, a University of Pennsylvania professor and lead author of the report. Despite questions about what a Facebook friend really means, "well, it turns out, it really means 'friend.'"

A Facebook spokesman declined to comment. Pew did a survey in 2008 that looked at measures of civic and social engagement, widely considered by social scientists to have increased over the past 20 years. The current survey, completed in October and November, found Americans in general have more close friends than they had two years before.

Hampton said he could not conclude that social media were causing the increase in friendship, but "if anything, the use of these technologies is associated with gains in this area, or has a neutral effect."