Sunk Cost and Commitment

Why the first request is small

It is small because it is not really a request for money. It is a request for a decision, and the amount is set at whatever will be agreed to without much thought.

Once it has been agreed to, something has changed that is worth more than the sum: you are now a person who helps him. Everything after that is consistent with a picture you have already painted of yourself.

The trap has two halves

Sunk cost. Money already gone starts to argue for money not yet gone. Stopping now means the earlier amount was wasted; continuing means it might still not have been. That reasoning is wrong in every textbook and almost impossible to feel your way out of, because it is not really about money. It is about what stopping would mean about you.

Consistency. People experience contradicting their own past choices as a kind of dishonesty. Having defended him to your daughter, refusing him next week is not just a decision about money, it is an admission that the defence was wrong.

Why it accelerates

Each step makes the next one smaller in relative terms. The person who sent two hundred is not deciding whether to send four thousand; they are deciding whether to send four thousand *given* that they have already sent two hundred, and to a version of the relationship that two hundred helped make real.

The way out is not arithmetic

Nobody has ever been argued out of this with a calculation, and pointing out the total tends to produce defensiveness rather than relief, because it sounds like an accusation of foolishness.

What works is changing the question. Not "should I send this", which invites the whole history back into the room, but "what would I advise someone else in exactly this position, knowing only what they know". The answer usually arrives immediately, and it is almost never the one being taken.