One reason for this has to do with a cognitive quality known as fluency, a measure of how easy a piece of information is to process. The brain automatically associates perceptual fluency, or ease of storage, with retrieval fluency, ease of recall.

Ein fehlerannotiertes Lernerkorpus des Deutschen als Fremdsprache

In recent years, cognitive scientists have shown that a few simple techniques can reliably improve what matters most: how much a student learns from studying.

The findings can help anyone, from a fourth grader doing long division to a retiree taking on a new language. But they directly contradict much of the common wisdom about good study habits, and they have not caught on.

For instance, instead of sticking to one study location, simply alternating the room where a person studies improves retention. So does studying distinct but related skills or concepts in one sitting, rather than focusing intensely on a single thing.

The current generation of machine learning algorithms can work well in Mediocristan but not in Extremistan. The very metrics these algorithms use, such as precision, recall, and root-mean square error (RMSE), make sense only in Mediocristan. It's easy to fit the observed data and fail catastrophically on unseen data. My hunch is that humans have evolved to use decision-making methods that are less likely blow up on unforeseen events (although not always, as the mortgage crisis shows).