A fascinating new study from Germany finds that revenge doesn't pay.
In a sane world, this would be no surprise. Energy spent on making someone else's life crap, is energy that's not working for oneself, or one's loved ones. In economic terms, it's simply a waste of resources. From Othello to Captain Ahab to the Count of Monte Cristo, our culture is full of illustrations of how revenge is a dish best not eaten at all.
The fact that this isn't considered blindingly obvious is probably because there are so many batshit-insane people around nowadays. In particular, believers in that beguiling branch of maths known as "game theory" - a category that, nowadays, includes almost everyone concerned with social sciences. Game theory, as popularly interpreted, implies that if someone does something bad to you, you should retaliate proportionately against them.
As far as it goes, the theory is fair enough. But it doesn't go nearly as far as many people think it does. Game theory, like every mathematical theory I've ever heard of, is based on a vast pile of mostly-unspoken assumptions that simply aren't true in the real world. For instance, there's the assumption that all players are following the same rules, which are not liable to change. Then there's the assumption that the number of players is constant - nobody will enter or leave the game mid-way. Or that all players have the same motivation. In most economic and social contexts, these assumptions are patently absurd. But they're so seldom stated that it's easy to forget they're there.
Now, thanks to Prof Dr Armin Falk of Bonn University and his co-authors, we have concrete evidence that "negative reciprocity" is truly counter-productive. In particular, the study finds, vengeful people are much more likely to find themselves unemployed.
What does work, on the other hand, is "positive reciprocity". Turns out that, regardless of the level of motivation, returning good behaviour leads to a much more profitable relationship than punishing bad behaviour.
What I like about this study is that it doesn't care about means or mechanisms. It doesn't try to prove, or even imply, that reward is a better motivator than punishment, or that relationships based on threat of punishment are unhealthy. It doesn't even try to argue with game theory. Maybe these things are true, maybe they aren't; that's not the point here. The point is that there is a measurable difference in outcomes.