Studies continue to show that once you have an idea of causality — that A causes B, usually because you saw A happen and then B happen — it's deucedly difficult to counter that idea, even with later information that A and B are not related.
This makes a certain measure of evolutionary sense — if Thag ate that strange purple flower and then had convulsions and died, the tribe can't afford to keep experimenting to see if the flower is actually safe and Thag already had a fatal illness. Better to print "Purple Flower BAD!" in big red letters in everyone's brain and move on. Sure, that may mean that a useful food source is discarded, but, well, remember poor Thag.
Conversely, Grug was wearing a squirrel-skin hat when he took down that lion. Clearly squirrel-skin hats help against dangerous animals, and we should all wear them, even if that later leads to squirrel bites and rabies. (And if another tribe shows up that doesn't wear squirrel-skin hats? Well, clearly they are a danger and need to be wiped out …)
The same argument can be made for any superstitious ritual, folk remedy, ideological conclusion, etc. The first out the gate to establish a connection between A (buy/pray/do this) and B (good thing!/bad thing!) has a huge advantage. First impressions matter.
The cost, of course, is lost opportunities, lack of pursuit of something that could be helpful (cf. the anti-vax movement), economic loss (e.g., costly quack medications), or secondary harms (rhinos hunted to extinction for their horns, human groups oppressed).
How to combat that psychological quirk in humans? Simply countering the information doesn't necessarily help, especially if there's an emotional stake in it before or after ("I've always liked what candidate X says, so if candidate X tells an anecdote linking A to B, I don't care what some academic study laterclaims in disproving it"). Meta explanations about how to think critically appear to help, but only in a limited way. Human brains have lots of tricks that serve well enough to keep most of us alive; it's the gaps where they don't, or actually hurt us, that are hard to overcome.
Your Brain Is Primed To Reach False Conclusions
Paul Offit likes to tell a story about how his wife, pediatrician Bonnie Offit, was about to give a child a vaccination when the kid was struck by a seizure. Had she given the injection a minute so…
