The Dawson Shooting and the Retro-Obvious.

[swestrup]

I pointed to this article on biases in human thinking a few days ago. It has suddenly become more relevant. In the wake of the recent shooting at Dawson, many folks have been asking "Why didn't realize this would happen and prevent it?" The answer, of course, is that no one knew. Many folks looking at the evidence from the blog have assumed it would have been obvious. The person was a Goth, they played violent video games, they posed with guns, etc, etc. Of course, it turns out that NONE of these are relevant factors in predicting violent behavior. In fact it turns out (read the article above) that folks are always far more willing to ascribe predictive values to such 'clues' after the fact than before. It seems that, once one knows the outcome, one is very likely to ascribe a high probability to the outcome, even if the evidence is lacking. Even when folks know this to be the case, they still think that things were obvious in retrospect when they would have said that nothing was predictable in advance.

This is yet another thing, in addition to numeracy and literacy, which I wished they taught journalists today.