A rumor started circulating back in 2008 that Barack Obama was not born in the United States. At the time, I was serving as chair of the Hawaii Board of Health. The director and deputy director of health, both appointed by a Republican governor, inspected Obama’s birth certificate in the state records and certified that it was real.
I would have thought that this evidence would settle the matter, but it didn’t. Many people thought the birth certificate was a fabricated document. Today, many people still believe that President Obama was not born in the U.S.
More recently, I was listening to a “Science Friday” podcast on the anti-vaccination movement. A woman called in who didn’t believe that vaccines were safe, despite overwhelming scientific evidence that they are. The host asked her how much proof she would need in order to believe that vaccines were safe. Her answer: No amount of scientific evidence could change her mind.
As a psychologist, I was bothered, but not shocked, by this exchange. There are several well-known mechanisms in human psychology that enable people to continue to hold tight to beliefs even in the face of contradictory information.
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