° CChildren aged 12 years compete with each other for worsening acts of self-harming websites.
They described that they wanted to become "better self-growing" and to combine the terrifying injuries they had seen to Tumblr, one of the sites they chose because the jobs received little attention.
This is the first time the researchers have managed to lift the experience of such sites after they have been approved for interviewing young self-destructors.
This will intensify the growing concern caused by the death of 14-year-old Molly Russell, who took her life after examining Instagram self-harm images.
This weekend, the Royal College of Pediatrics and Children's Health (RCPCH) has called for urgent action by social media companies to tackle self-harm and support demands for an independent regulator.
Dr. Max Davy, RCPCH Health Promotion Officer, said: "We know the rate of self-harm is high and rising, especially among young girls, and therefore the apparent increase in self-harming bills is very worrying.
"The combination of social media incentives that need to be noticed and the lack of effective regulation can be toxic and can contribute to this rise."
Ministers must announce plans for new laws to regulate social media next month after a telegraph campaign for a statutory care duty.
The University of Cardiff study found that some young people have started harming themselves because the Internet provides a catalyst. But most of them are already self-growing and go online to "understand their behavior".