"If I concede this, I'll have to concede everything"

There's a floodgate belief. One climb-down and the wall's breached. If you admit the roundabout, then the supplier figures are next, and the film, and before long you're someone who's wrong about everything and knows it. Better to hold the small ones so the big ones stay dry.

Peter Kim and colleagues ran two studies in 2004 on how trust gets repaired after someone's been accused of a lapse, and the answer depended on what kind of lapse it was. When the matter was competence, getting something wrong, an apology repaired trust better than a denial. When the matter was integrity, being dishonest, a denial worked better, provided the person really was innocent. The reason is what each response says about you. An apology for a competence lapse says "I got that one wrong and I can see it." A denial of a competence lapse, when the evidence is against you, says something worse.

Now put that next to holding. Being wrong about the roundabout is a competence matter, and a small one. Everyone is wrong about roundabouts. The climb-down treats it as what it is and repairs it in one sentence. Holding does something odd. It takes a competence matter and, by making you defend something you can see is false, turns it into an integrity one. The question in the other person's head changes from "did they know about the roadworks" to "are they going to keep saying that when they obviously know." That's a bigger question, and denial doesn't help you with it, because the evidence is on the table.

So the floodgate runs the other way from the belief. Each small climb-down closes something. It keeps the roundabout a roundabout. Each hold opens something, because it invites the integrity question, and once that's open it colours everything else you say. The person who admits the small ones is the person whose big claims get believed, because they've shown their claims are the kind that get withdrawn when wrong.

I'm extending Kim's finding from the workplace it was tested in to the car, so take the application as my reading. But the shape of it is one you've seen. Think of someone you know who never admits the small ones. Now think about how much weight you give their big ones.