A bit of a followup to this earlier post on how humans prefer cockiness to experience is something known as the Dunning-Kruger effect:

"...because people who are unskilled in these domains suffer a dual burden: Not only do these people reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the metacognitive ability to realize it."

and

It beautifully explains the utter confidence of those who, with no expertise, remain stubborn in their views regardless of overwhelming evidence. It makes you want to shake them by the collar and scream about how stupid they are. But evidence shows that's not the best strategy.

Via Boingboing and ABC Radio in Australia.