So why did the Riksbank make such a terrible mistake? That’s a hard question to answer, because officials changed their story over time. At first the bank’s governor declared that it was all about heading off inflation: “If the interest rate isn’t raised now, we’ll run the risk of too much inflation further ahead ... Our most important task is to ensure that we meet our inflation target of 2 percent.” But as inflation slid toward zero, falling ever further below that supposedly crucial target, the Riksbank offered a new rationale: tight money was about curbing a housing bubble, to avert financial instability. That is, as the situation changed, officials invented new rationales for an unchanging policy.

In short, this was a classic case of sadomonetarism in action.

I’m using that term (coined by William Keegan of The Observer) advisedly, not just to be colorful. At least as I define it, sadomonetarism is an attitude, common among monetary officials and commentators, that involves a visceral dislike for low interest rates and easy money, even when unemployment is high and inflation is low. You find many sadomonetarists at international organizations; in the United States they tend to dwell on Wall Street or in right-leaning economics departments. They don’t, I’m happy to say, exert much influence at the Federal Reserve — but they do constantly harass the Fed, demanding that it stop its efforts to boost employment.

And when I say that the dislike for low rates is visceral, I mean just that. While sadomonetarists may offer what sound like coherent analytical rationales for their policy views, they don’t change their policy views in response to changing conditions — they just invent new rationales. This strongly suggests that what we’re looking at here is a gut feeling rather than a thought-out position.

Indeed, the Riksbank’s evolving justifications for rate hikes were mirrored at international organizations like the Switzerland-based Bank for International Settlements, an influential bankers’ bank that is a sadomonetarist stronghold. Just like the Riksbank, the bank changed its rationale for rate hikes — It’s about inflation! It’s about financial stability! — but never its policy demands.

Where does this gut dislike for low rates come from? At some level it has to reflect an instinctive identification with the interests of wealthy creditors as opposed to usually poorer debtors. But it’s also driven, I believe, by the desire of many monetary officials to pose as serious, tough-minded people — and to demonstrate how tough they are by inflicting pain.