Anchoring Bias pulls an unknown value toward a known anchor
or "Anchoring Effect"
Anchoring bias is the tendency to rely too heavily, or “anchor,” on one trait or piece of information when making decisions. It occurs when people consider a particular value for an unknown quantity before estimating that quantity.
From Thinking, Fast and Slow – Kahneman (2013), ch. 11:
It occurs when people consider a particular value for an unknown quantity before estimating that quantity.
…
Any number that you are asked to consider as a possible solution to an estimation problem will induce an anchoring effect.
…
adjustment is a deliberate attempt to find reasons to move away from the anchor: people who are instructed to shake their head when they hear the anchor, as if they rejected it, move farther from the anchor, and people who nod their head show enhanced anchoring.
…
Insufficient adjustment is a failure of a weak or lazy System 2.
…
The psychological mechanisms that produce anchoring make us far more suggestible than most of us would want to be.
…
My advice to students when I taught negotiations was that if you think the other side has made an outrageous proposal, you should not come back with an equally outrageous counteroffer, creating a gap that will be difficult to bridge in further negotiations. Instead you should make a scene, storm out or threaten to do so, and make it clear—to yourself as well as to the other side—that you will not continue the negotiation with that number on the table.
See also: