The Anchoring Effect

Key Insight

The anchoring effect is a highly reliable and robust psychological phenomenon where people's estimates of an unknown quantity are systematically influenced by a particular value they considered beforehand. This initial value, or 'anchor,' pulls subsequent estimates closer to itself, even if it is completely irrelevant or arbitrary to the actual quantity being estimated.

Experiments demonstrate this absurdity vividly. When participants were asked to estimate the percentage of African nations in the UN, their average estimates were significantly higher (45%) if an irrelevant wheel of fortune had stopped at 65, compared to 25% if it had stopped at 10. This shows that judgments were swayed by an obviously uninformative number.

The effect is widespread in everyday life. For example, considering a high asking price for a house makes it seem more valuable, even if one tries to resist its influence. Any number presented as a possible solution or comparison point for an estimation problem can induce this powerful anchoring bias, illustrating how judgments stay close to the initial reference point.