In 2007, the artist Lars Vilks upset a large number of people by depicting the Islamic prophet Muhammad as a roundabout dog. In March 2010, eight people were arrested for plotting to murder Vilks.
We followed Vilks in Swedish social media during the spring of 2010, using a metric called the Violence Propensity Index (VPI) to quantify the expressions of violent language targeting Vilks. Image 1 illustrates how events unfolded.
On May 11, 2010 Vilks was assaulted while giving a lecture on free speech at Uppsala University. A few days later, on May 15, Vilks’ house was attacked by arsonists. Note the significant rise in VPI on the day before both attacks! What’s more: a public appearance by Vilks planned to May 4 was cancelled. There’s a rise in VPI on May 3, too!
Now, we’re not claiming that the bloggers did it. What we do say, however, is that the attitude towards a given subject, as expressed in on-line social media, may well reflect the attitudes at large in a population, including people who are about to take action and externalize their opinions. The VPI is a means to detect (weak) signals of violent chatter, and as such, may facilitate an early warning pertaining to targets at risk.