When I was living in Canada, we asked people how much money they would be willing to pay to clean lakes from acid rain in the Halliburton region of Ontario, which is a small region of Ontario. We asked other people how much they would be willing to pay to clean lakes in all of Ontario. People are willing to pay the same amount for the two quantities because they are paying to participate in the activity of cleaning a lake, or of cleaning lakes. How many lakes there are to clean is not their problem.

This is a mechanism I think people should be familiar with. The idea that when you’re asked a question, you don’t answer that question, you answer another question that comes more readily to mind. That question is typically simpler; it’s associated, it’s not random; and then you map the answer to that other question onto whatever scale there is.

We assume that more information will make it easier to find the cause, that seeing the soft tissue of the back will reveal the source of the pain, or at least some useful correlations. Unfortunately, that often doesn’t happen. Our habits of visual conclusion-jumping take over. All those extra details end up confusing us; the more we know, the less we seem to understand.

[M]uch of what biomedical researchers conclude in published studies—conclusions that doctors keep in mind when they prescribe antibiotics or blood-pressure medication, or when they advise us to consume more fiber or less meat, or when they recommend surgery for heart disease or back pain—is misleading, exaggerated, and often flat-out wrong.

‘No single narrative emerges from this broad and often contradictory collection of interpretations, but the sheer variety of conclusions is informative.’

It is an instructive look at how bad we are at discovering the truth and talking about it.