The phenomenon known as ‘mass psychogenic illness’ (MPI) – in which a group of people starts feeling sick with similar symptoms in the absence of a clear physical reason – is nothing new. Indeed, the historical record dates back to medieval Europe – including one notorious case in which nuns were reported to be meowing in unison like cats. In Believing Is Seeing, Robert Bartholomew, a sociologist at the University of Auckland, argues that our exceedingly interconnected world of social media is just as conducive for social panics as secluded medieval convents once were. Focusing on a trend in which tic disorders seem to spread via TikTok videos, Bartholomew breaks down why this ‘placebo effect in reverse’ can still cause genuine illness, as well as why he believes that social media should come with more guardrails. Believing Is Seeing is part of the 2022 short film collection from the New Zealand filmmaking initiative Loading Docs.