Tendency for people to adjust their (numerical) judgments towards the first piece of information.
Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131.
Participants are first asked to estimate whether a quantity (e.g., the number of gold medals won by Japan at the 2012 Summer Olympics) is more or less than a given value (anchor) and then to provide their estimate. Eight pairs of items are used, where items in each pair involved similar quantities (e.g., the number of gold medals won by Japan/Australia at the 2012 Summer Olympics [actual number: 35]) but different anchors, with either a low or a high anchor corresponding to 10% or 190% of the actual number. The 16 items are presented in a random order.
In each pair, the anchoring bias score is calculated as follows:
(estimate [high anchor] – estimate [low anchor]) / (high anchor – low anchor)
The total score is the average of the eight scores.
Berthet, V., Autissier, D., & de Gardelle, V. (2022). Individual differences in decision-making: A test of a one-factor model of rationality. Personality and Individual Differences, 189, 111485.
See also:
Teovanović, P., Knežević, G., & Stankov, L. (2015). Individual differences in cognitive biases: Evidence against one-factor theory of rationality. Intelligence, 50, 75–86.
Teovanović P. (2019). Individual Differences in Anchoring Effect: Evidence for the Role of Insufficient Adjustment. Europe's journal of psychology, 15(1), 8–24.