Confirmation bias

Confirmation bias (also confirmatory bias, myside bias, or congeniality bias) is the tendency to search for, interpret, favor and recall information in a way that confirms or supports one's prior beliefs, values, or decisions. 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, emotionally charged issues and deeply entrenched beliefs. Confirmation bias often comes from automatic mental habits. Studies repeatedly find that people tend to test ideas in a one sided way, mainly searching for evidence that supports what they already assume. Research on selective exposure also suggests that people differ in how strongly they defend their attitudes, with some individuals being more resistant to information that goes against their views. 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 despite the different parties being 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 (when people falsely perceive an association between two events or situations). A series of psychological experiments in the 1960s suggested that people are biased toward confirming their existing beliefs. Later work reinterpreted these results as a tendency to test ideas in a one-sided way, focusing on one possibility and ignoring alternatives. Explanations for the observed biases include wishful thinking and the limited human capacity to process information. Another proposal is that people show confirmation bias because they are pragmatically assessing the costs of being wrong rather than investigating in a neutral, scientific way. Flawed decisions...