Confirmation Biases
From Impressions to Reality It is a striking feature of human nature but often true: Once people make up their minds about something—even if they don’t have all the necessary information— they become reluctant to change their minds when confronted with new evi- dence. People can be quite intellectually stubborn. Political leaders often refuse to withdraw support for government programs that don’t work, and scientists often steadfastly defend their pet theories in the face of contradictory research data. These instances are easy to explain. Politicians and scientists have personal stakes in their opinions, as votes, pride, funding, and reputation may be at risk. But what about people who more innocently fail to revise their opinions, often to their own detriment? What about the baseball manager who clings to old strate- gies that don’t work or the trial lawyer who consistently selects juries according to false stereotypes? Why are they often slow to face the facts? As we will see, people are subject to various confirmation biases—tendencies to interpret, seek, and create information in ways that verify existing beliefs.
Events that are ambiguous enough to support contrasting interpretations are like inkblots: We see or hear in them what we expect to see or hear. Illustrating the point, one group of researchers had people rate from photographs the extent to which pairs of adults and children resembled each other. Interestingly, the participants did not see more resemblance in parents and offspring than in random pairs of adults and children. Yet when told that cer- tain pairs were related, they did “see” a resemblance, even when the relatedness information was false
