Anchored Numbers

[A]nchoring — when you don't know the answer to something, whatever starting point you have plays a powerful role in determining what you think is the right answer.

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A Johns Hopkins study published in a respected peer-reviewed journal finds the number of Iraqis killed as a consequence of the 2003 invasion to be about 650,000.

Critics immediately get up in arms; U.S. President George W. Bush declares the result "not credible."

Although the debate over the study has been largely driven by the political implications of the number of Iraqi casualties, psychologists say the fact that many Americans find the new number hard to digest is a perfect example of anchoring>.

Previous estimates had put the number of Iraqi casualties at 30,000 to 50,000. Once that number was anchored in people's minds, it was a foregone conclusion that most people would find it very difficult to accept a much larger number.