Often groups of people behave in consistent ways for a long time because they share a belief that the consistent way everyone is behaving will cause things to be bad for any individual who deviates from it.

For instance, there is a line in the sandwich shop. From a perspective so naive to our ubiquitous norms that it is hard to imagine, you might wonder why the person standing at the back does so, when the shopkeeper is much more likely to get sandwiches for people at the front. The reason of course is that if he were to position himself in the ample physical space between the person at the front and the shopkeeper, there would be some kind of uproar. Not only would the person at the front be angry, but everyone in the line would back them up, and the shopkeeper probably wouldn’t even grant a sandwich to the line-jumper.

So key to our ubiquitous tendency to stand peacefully in line is the fact that our common behavior is ‘stand in line and get angry with anyone who jumps it’ not just ‘stand in line’ which would be immediately exploited until the norm upholder gave up or died of starvation.

An interesting thing about this extra clause is that it is about our hypothetical behavior in circumstances that rarely happen. If our norms work well enough, we might go for years all peacefully standing in line, without anyone ever trying to push in at the front, because why would they?

An upshot is that if serious norm violations are rare, people might become pragmatically ill-equipped to respond to them. They might forget how to, or they might stop having the right resources to do so, physical or institutional. Or if generations are passing with no violations, the new generation might just fail to ever learn that they are meant to respond to violations, or learn what that would look like, since they never observe it. And maybe nobody notices any of this until norms are being violated and they find they have no response.

For instance, suppose that occasionally people sort of wander toward the front of the line in ambiguous circumstances, hoping to evade punishment by feigning innocent confusion. And those in the line always loudly point out the ‘error’ and the room scowls and the person is virtually always scared into getting in line. But one day someone just blatantly walks up to the front of the line. People point out the ‘error’ but the person says it is not an error: they are skipping the line.

The people in the line have never seen this. They only have experience quietly mentioning that they observe a possible norm violation, because that has always been plenty threatening. Everyone has become so used to believing that there is terrifying weaponry ready to be pulled out if there really were a real norm violation, that nobody has any experience pulling it out.

And perhaps it has been so long since anyone did pull it out that the specific weapons they stashed away for this wouldn’t even work any more. Maybe the threat used to be that everyone watching would gossip to others in the town about how bad you were. But now in a modern sandwich shop in a large city, that isn’t even a threat.

The world is full of sufficiently different people that in the real world, maybe someone would just punch you in the face. But it seems easy to imagine a case where nobody does anything. Where they haven’t been in this situation for so long, they can’t remember whether there is another clause in their shared behavior pattern that says if you punch someone because they got in line in front of you at the sandwich shop that you should be punished too.

Does this sort of erosion of unexercised threats actually happen? I am not sure. I think of it if for instance a politician behaves badly in ways that nobody had even thought of because they are so obviously not what you do; and then get away with it while onlookers are like ‘wait, what?! You can’t do that!’ But I don’t know enough details of such cases to judge whether they are cases of threat erosion.

Another case where I guess people might experience this is in bringing up children, because threats of punishment are often made, and the details of the relationship is changing as the children change, so if you don’t exercise the threats they can cease to be relevant without you noticing.

I probably saw something close to this in looking after my brothers. My brothers were into fighting for fairness and justice, where ‘fairness’ is about one’s right to have stuff someone else has, and ‘justice’ is about meeting all slights with tireless bloodthirsty revenge. So my main task was dealing with fights, and threats were relevant. When my brothers were small, I was physically in control of what they could have or eat or punch, so could uphold threats. Later they were really big and I couldn’t have enforced any threats if they decided to make it a physical conflict. This hadn’t been strongly tested by the time it dawned on me, and I continued to bluff. But there was perhaps an earlier period when I didn’t realize I was now bluffing, where if they had realized first, I would have been left with no response. This isn’t quite a case, because noticing that my threats were decaying didn’t let me strengthen them. But had I been an adult in charge of money and the car and such, things may have been different.

I’m not sure if such a situation would last for long in important cases where a replacement threat is feasible. If violations are still clearly bad for a set of people who have general resources to invest in threats, I’d often expect a new and compelling response to be invented in time.