From the COVID-19 pandemic to the war in Ukraine, misinformation is rife worldwide. Many tools have been designed to help people spot misinformation. The problem with most of them is how hard they are to deliver at scale.

But we may have found a solution. In our new study we designed and tested five short videos that “prebunk” viewers, in order to inoculate them from the deceptive and manipulative techniques often used online to mislead people. Our study is the largest of its kind and the first to test this kind of intervention on YouTube. Five million people were shown the videos, of which one million watched them.