Nine of 10 teenagers have witnessed bullying on social networks, study finds

10 girls ages 12 to 13 said they have experienced mostly unkind treatment on social networks, according to the report. Lenhart and other experts on social media said teenagers see themselves differently online than in the real world. Some assume a sort of “alter ego” on the Web, engaging in conversation with more bravado and taking more risks than they do when face to face with a peer, she said.

Peers can be particularly cruel on sites such as FormSpring that allow users to post comments anonymously, or on the comment boards of sites such as YouTube, according to experts. Facebook — with 800 million global users — requires its members to use their real identities, which it thinks is one way to prevent anonymous bullying. It also allows users to block photos of and comments about themselves that they don’t like. But that hasn’t stopped all bullying. And some experts worry that younger adolescents are particularly vulnerable. Rachel Simmons, an author and speaker on children and social media, said bullying occurs most in middle school, yet parents are often helping their children get online when they are younger than 13, the minimum age required for Facebook. “The younger the kid, the meaner the peer group becomes, so this is an alert to parents that not every kid is ready for the independence of having their own social networking page,” Simmons said.