In short, your own mind acts like a compulsive yes-man who echoes whatever you want to believe. Psychologists call this mental gremlin the "confirmation bias." A recent analysis of psychological studies with nearly 8,000 participants concluded that people are twice as likely to seek information that confirms what they already believe as they are to consider evidence that would challenge those beliefs.

Why is a mind-made-up so hard to penetrate?

"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 support our hypothesis, rather than to seek out evidence that might disprove it."

The more you learn, the more certain you become that you are right. While gathering more data makes people more confident, it doesn't make their predictions much more accurate. Each new fact makes you more inclined to find another fact that resembles it, reducing the diversity and value of your information.