Anchoring effect

Phenomenon that if a person is asked to estimate the value of a quantity this estimate will be biased towards any value which has previously been given, even when the person knows that the latter value was randomly determined.

The process involves a “rule-of-thumb” or heuristic adjustment made to the initial value – know as the “anchor” – which value may be explicitly supplied or specified (as above), suggested by the formulation of the problem at hand, or be the product of a partial computation, for example, concerning an estimate of a probability.

This effect is noteworthy because anchors affect actors’ judgements: the adjustments people make are seldom sufficient and, depending upon the particular case, may generate wildly inaccurate results.