 As news of the apparent wave of damage spread, more and more people checked their windshields, discovered that their windshields too had been damaged, thus confirming belief in the supposed epidemic.In fact, the windshields were previously damaged, but the damage went unnoticed until people checked their windshields as the delusion spread.One factor in the appeal of alleged psychic readings is that listeners apply a confirmation bias which fits the psychic's statements to their own lives.