For example, consider a narrow river valley below a high dam, such that if the dam burst, the resulting flood of water would drown people for a considerable distance downstream. ... Surprisingly, though, after you get to just a few miles below the dam, where fear of the dam’s breaking is found to be highest, the concern then falls off to zero as you approach closer to the dam! ... That’s because of psychological denial: the only way of preserving one’s sanity while looking up every day at the dam is to deny the possibility that it could burst.

Norsemen with their own heavy wooden rowboats and their own techniques for hunting walruses and seals must have recognized the superior sophistication of Inuit light skin boats and hunting methods: the Inuit were succeeding at doing exactly what the Norse hunters were trying to do. When later European explorers began visiting Greenland in the late 1500s, they were immediately amazed at the speed and maneuverability of kayaks and commented on the Inuit appearing to be half-fish, darting around in the water much faster than any European boat could travel.

Religious values tend to be especially deeply held and hence frequent causes of disastrous behavior. For example, much of the deforestation of Easter Island had a religious motivation: to obtain logs to transport and erect the giant stone statues that were the object of veneration.

Politicians use the term “creeping normalcy” to refer to such slow trends concealed within noisy fluctuations. If the economy, schools, traffic congestion, or anything else is deteriorating only slowly, it’s difficult to recognize that each successive year is on the average slightly worse than the year before, so one’s baseline standard for what constitutes “normalcy” shifts gradually and imperceptibly. It may take a few decades of a long sequence of such slight year-to-year changes before people realize, with a jolt, that conditions used to be much better several decades ago, and that what is accepted as normalcy has crept downwards.