National hindsight bias day

For balance I follow a few people on Twitter at the opposite end of the political spectrum. I consciously try to avoid confirmation bias, and regularly find there is much agreement across what are often imaginary political divides.

One thing I’ve noticed today, in the aftermath of the Sydney siege, is that the right-wing - the conservatives and nationalists - seem more likely to be suffering a serious dose of hindsight bias, which is

… the inclination, after an event has occurred, to see the event as having been predictable, despite there having been little or no objective basis for predicting it, prior to its occurrence

Many on the right are arguing that because the perpetrator had a criminal history it should have been obvious that he was a risk of committing this sort of insanity.

But this is almost never the case. Almost everyone with a criminal history does not do this. The sheer rarity of such an event is what is causing the media fanfare, and the sheer rarity is why such things cannot be easily foreseen in advance, despite our retrospective justification.

The gunman could have been just about anyone and we would have latched on to some feature of his life that in retrospect appears to offer a prediction of future radical behaviour. Any strange hobby, personality quirk, or previous emotional breakdown would appear to be a reliable signal after the fact.

The world is full of nut-jobs.

I’m quite pleased to see religious leaders joining together, and the community coming to support each other. We should all be thankful that such events are so rare.

In any case, given some of the reactions I want to declare today National Hindsight Bias day.