We've already established their irrationality. They're more afraid of a 3-in-a-million chance of something versus a 5000-in-a-million chance of the same thing v

We've already established their irrationality. They're more afraid of a 3-in-a-million chance of something versus a 5000-in-a-million chance of the same thing via a passive path. The question is why. I do agree that social media can amplify the effect, but so can two people who share the same fear sitting in the same room. How did those two people get that fear in the first place?