If you talk to strangers on Facebook, you must read this

The team from Michigan State University found that adults with Williams syndrome, who are extremely social and trusting, use Facebook and other social networking sites frequently and are especially vulnerable to online victimisation.

“You have this very social group of people who are vulnerable in real life and now they are seeking a social outlet through the internet, communicating with people they know and don't know," said Marisa Fisher, assistant professor of special education. “They don't have the training or the knowledge to know how to determine what is risky behaviour,” Fisher added.

Roughly a third of participants said they would send their photo to an unknown person, arrange to go to the home of a person they met online and keep online relationships from their parents. Williams syndrome is a relatively rare genetic disorder characterised by developmental delays, learning disabilities, excessively social personalities and an affinity for music.

Nearly 86 per cent of adults with Williams syndrome use social networking sites such as Facebook nearly every day, typically without supervision, found the study published in the Journal of Intellectual Disability Research. Participants also share a large amount of identifiable information on their social network profiles and are likely to agree to engage in socially risky behaviours.

The findings suggest people with the syndrome can learn to say no to strangers, refuting past studies that indicated sociability may be hard-wired in individuals with Williams syndrome. “It's time to start teaching individuals with Williams syndrome about safety, both in the real world and online," Fisher added. This includes what personal information they should share, how to set privacy settings and how to decide whether an 'online friend' should become an “offline friend.”