Cyberbullying has become a scourge of social media, but artificial intelligence is learning to detect and filter out hurtful posts before they reach vulnerable users.

About one-third of teenagers say they have been bullied online. Some victims have taken their own lives – including 14-year-old Australian schoolgirl Amy Everett in January – prompting governments to introduce harsher penalties for perpetrators . However, these measures fail to prevent exposure to cyberbullying in the first place.

Gilles Jacobs at Ghent University in Belgium and his colleagues wondered if they could train …