The deterrent that did not deter

A school introduced a fine of ten thousand dong for arriving late to the after-school club. The aim was obvious: fewer late arrivals. Lateness rose.

The same experiment has been run properly, at ten nurseries in Israel, where a small fine was introduced for parents who collected children late. Late collections roughly doubled and stayed high. When the fine was removed, they did not return to the old level.

The explanation is about what a rule communicates. Before the fine, arriving late meant imposing on a teacher who had stayed behind, and most parents felt that as an obligation they did not want to break. The fine replaced that obligation with a price. Once lateness had a price, it became a service you could buy, and ten thousand dong for twenty extra minutes is cheap.

What makes the case uncomfortable is the second half. Removing the fine did not restore the original feeling, because the original feeling depended on nobody ever having put a number on it. A relationship that has been priced once is difficult to un-price.

This matters whenever a school considers a penalty. A deterrent works if it raises the cost above what people will pay. A small penalty can lower the perceived cost to zero by converting a social duty into a transaction, which is the opposite of what was intended and considerably harder to undo.