We don’t follow the herd unless it helps us fit in

Connected The Amazing Power of Social Networks and How They Shape Our Lives

This mysterious attacker would open bedroom windows late at night and spray victims with a “sweet-smelling” anaesthetic gas that would temporarily paralyse them but, even more bizarrely, leave others in the same room unaffected.

Investigators acknowledged the possibility that this evil genius might exist. But they also made clear there was a much more likely explanation — that it was a straightforward case of epidemic hysteria, whereby one person’s emotional fears became contagious in a town of 15,000 people. Epidemic hysteria nowadays goes by the distinctly duller title of mass psychogenic illness (MPI), but the cause and effect remain the same: “Like a single startled buffalo within a herd,” the authors note, “a single emotional reaction in one person can sometimes cause many others to feel the same thing, creating an emotional stampede.”