[grkvlt]

The thing is, an 'average person' has no real idea or mental model of what five years in prison actually entails. They haven't been locked up ever, even for shorter stretches, and most likely neither have their friends. Basically they know its bad, but with no frame of reference it gets left at that and filed away as irrelevant anyway since prison happens to other, bad people. So there's no way to make a risk calculation about e.g 6mo vs 5y sentences, they are both just vague bad things. Monetary fines work because people understand money and what losing a sum of money means because they deal with money all the time. I assume corporal punishment works too, since everyone has experience with pain?