10 November 2011
Amos and I once rigged a wheel of fortune. It was marked from 0 to 100, but we had it built so that it would stop only at 10 or 65 One of us would stand in front of a small group, spin the wheel, and ask them to write down the number on which the wheel stopped, which of course was either 10 or 65. We then asked them two questions:
Is the percentage of African nations among UN members larger or smaller than the number you just wrote?
What is your best guess of the percentage of African nations in the UN?
The spin of a wheel of fortune had nothing to do with the question and should have had no influence over the answer, but it did. “The average estimate of those who saw 10 and 65 were 25% and 45 respectively.”
This is known as “the anchoring effect,” of which Kahneman explains in his book, “We were not the first to observe the effects of anchors, but our experiment was the first demonstration of its absurdity.” It’s unsettling to know that your judgment can be so heavily influenced by some random number and disturbing to realize it is probably happening all the time. The anchoring effect turns out to explain all sorts of strange phenomenon in the world around us—why, for instance, when German judges, before mock-sentencing a shoplifter, were asked to roll a pair of dice rigged to come up either three or nine, those who rolled nine said on average eight months, while those who rolled three said five months.
~ By Michael Lewis ~
The King of Human Error • Opuss № I