If there’s one lesson to be learned from the Shannon Matthews affair, it’s that there are no lessons to be learned.

Put it this way. Human nature being as it is, some welfare mums are criminals, some are heroes struggling under terrible circumstances, and many are just ordinary folk. There’s a distribution of qualities.

But we can infer nothing at all about the shape of any distribution, or its average or standard deviation, from just seeing one extreme data-point.

So, how come so many people think they can “learn lessons”?
Cognitive biases, that’s how.