The impetus behind feuds

A total of 192 volunteers took part in computerised games in which two players were given an initial probability of winning £10. Each could take turns to “steal” a percentage of their opponent’s winning probability but in doing so gain only a fraction of that probability himself. A game ended if neither chose to steal or when both had less than a 10 per cent chance of winning the money.The results suggest that, when vendettas are allowed to develop, the protagonists are likely to pursue their feud well beyond the expected and reasonable limits of self-interest, usually resulting in an undesirable outcome for both parties.