We’re all mentally lazy," says psychologist Scott Lilienfeld of Emory University in Atlanta. "It’s simply easier to focus our attention on data that supports our hypothesis, rather than to seek out evidence that might disprove it.

http://online.wsj.com/article/SB10001424052748703811604574533680037778184.html?mod=WSJ_hpp_LEFTTopStories

(I like to think of confirmation bias as “relentless optimism in face of constant disappointment” )