Confirmation Bias
Confirmatory Bias · Myside Bias
The tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities.
Origin
English psychologist Peter Wason first described confirmation bias in the 1960s through experiments published in 1960, refining it as "a preference for information that is consistent with a hypothesis rather than information which opposes it." In Wason's classic 2-4-6 task, participants repeatedly challenged to identify a rule applying to number triples were told that (2,4,6) fits the rule. The actual rule was simply "any ascending sequence," but participants had great difficulty finding it, announcing far more specific rules. They tested only positive examples—triples obeying their hypothesized rule—rather than testing violations that would falsify it. Wason's work set in motion the study of cognitive biases, predating Tversky and Kahneman's famous heuristics and biases program.