anchoring bias

Meaning: Anchoring is a cognitive bias in judgment and decision making, described in the heuristics-and-biases work of Tversky and Kahneman. A person starts from an initial value, the anchor, and adjusts from it, but the adjustment is typically too small. The final estimate is therefore pulled toward the anchor. The anchor can be irrelevant, such as a random number, and still influence the answer.

On the MCAT: A passage describes participants who first see a high or low number (a spun wheel, a list price, a first salary offer) and then estimate a quantity such as the percentage of African countries in the UN or the value of an item. You predict that the high-anchor group gives higher estimates than the low-anchor group. Negotiation and pricing examples are common: the first offer sets the range for the counteroffers.

Common confusion: Anchoring is often mixed up with the availability heuristic and with confirmation bias. Availability means judging likelihood by how easily examples come to mind. Confirmation bias means seeking or favoring evidence that supports an existing belief. Anchoring is about a starting number or first impression that skews later numerical or evaluative judgments, even when the person knows the anchor is unrelated. It is also different from the primacy effect, which is better recall of items presented first in a list.