Before moving on the the DAP section, I would like to point out that the creator of this thread, xnor, posted an article from a magazine and wanted to know why this is the case:
If someone holds a belief and is shown scientific evidence that contradicts it, they will often be strengthened in their belief instead of revising it. Why is this the case?
I tried to give a possible answer:
Does anyone have any other thoughts as to why it can be like this?
My answer is in three parts.
A simple because saying sorry is the hardest thing to do. By saying sorry you are admitting that you were wrong and we don't like to do that anymore. Politicians, big business, banks, people used to admit to their mistakes and resign with honour. We rarely do that anymore.
Secondly, authority has been eroded and the general public is more questioning. A doctor saying there is nothing else they can do was accepted with a thanks. Now people want a second or third opinion. (Generalisation to make a point).
Thirdly, particularly with the internet it is much easier now to find others who share you own opinion, even wild and wacky ones. Having others reinforce your beliefs makes it easier to retain them, no matter the contrary arguments.