The reason for this cognitive disconnect is that:
- We have evolved brains that pay attention to anecdotes because false positives (believing there is a connection between A and B when there is not) are usually harmless
- Whereas false negatives (believing there is no connection between A and B when there is) may take you out of the gene pool.
- Our brains are belief engines that employ association learning to seek and find patterns.
Superstition and belief in magic are millions of years old, whereas science, with its methods of controlling for intervening variables to circumvent false positives, is only a few hundred years old. So it is that any medical huckster promising that A will cure B has only to advertise a handful of successful anecdotes in the form of testimonials