Say you are looking at a car’s seatbelt for the first time in a showroom.
The salesperson tells you how the belt prevents your head from hitting the dashboard in case of an accident. You put on the belt and slowly lean forward, until your head makes contact with the dashboard. You then give her an indignant look. How is this loose cord supposed to save you when you meet an accident? And who were the dumb folks who designed it?
The salesperson then asks you to yank the belt forcefully. You now notice how the belt won’t extend anymore, no matter how hard you pull. Those engineers at Toyota weren’t stupid after all.
The seatbelt rule is simple. It states that the lesser we know about something, the more we must discount the conclusions that our minds are likely to make about it.
We are prone to being too confident about things we don’t understand well. The seatbelt rule is an antidote to this overconfidence.