Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that confirms or supports one's prior beliefs or values. People display this bias when they select information that supports their views, ignoring contrary information, or when they interpret ambiguous evidence as supporting their existing attitudes. The effect is strongest for desired outcomes, for emotionally charged issues, and for deeply entrenched beliefs. Confirmation bias cannot be eliminated, but it can be managed, for example, by education and training in critical thinking skills.
Biased search for information, biased interpretation of this information, and biased memory recall, have been invoked to explain four specific effects:
attitude polarization (when a disagreement becomes more extreme even though the different parties are exposed to the same evidence)
belief perseverance (when beliefs persist after the evidence for them is shown to be false)
the irrational primacy effect (a greater reliance on information encountered early in a series)
illusory correlation...