"I've done it a thousand times"

This is the belief under all the others, and it's the one that feels least like a belief and most like a fact. You've peeked at the phone hundreds of times, maybe thousands, over years, and nothing has happened. Not a scrape. Not a swerve. The clean sheet is real and it's long, and every time you look it gets one longer. What could be better evidence than your own record?

Here's the figure the record is up against. Redelmeier and Tibshirani, in 1997, took six hundred and ninety-nine drivers who'd had a collision and who owned a mobile phone, and got the phone company's billing records for the day of the collision and for the same time the week before. A driver on a call was about four times as likely to be in a collision as the same driver not on a call. Within five minutes of a call it was nearly five times. The comparison is each driver against themselves, which removes the argument that phone users are just worse drivers.

Now think about what fourfold means for a rare thing. A collision on any given drive is very unlikely. Four times very unlikely is still unlikely. So a person who peeks on every drive for a year will, most years, have nothing happen, and will have a clean sheet a year longer, and will feel more sure than ever that they're the exception. The clean sheet isn't evidence that the risk is small. It's what a fourfold risk of a rare thing looks like from the inside, right up to the one drive where it doesn't.

You've crossed a road without looking because it's always empty at that hour. The record was clean there too, up to the morning it wasn't, and the record was never the reason it was empty. That's the whole of the analogy and it's the only one in this chapter.

There's a general version of this that Neil Weinstein described in 1980. He asked students to rate their own chances of good and bad events against their classmates', and they put themselves above average for the good ones and below for the bad. He called it unrealistic optimism and one of the things that fed it was personal experience. The more often something hasn't happened to you, the less likely it feels, whatever the numbers say. If that pattern is familiar from the other direction, from worrying about things that never come, the book It hasn't happened yet is about it. This is the same machinery running the other way, and it runs the seat belt and the helmet too.

The thousand isn't a sample of what happens when you peek. It's a sample of what happens when you peek and nothing's there. The one that matters hasn't been in the sample yet. That's not a scare, it's just what the clean sheet is made of.