Biases and effectsTversky and Kahneman, 1974
The first number you see drags every judgment after it. The whole mechanism of "was 9,800, now 3,980".
The classic study: a wheel is spun and lands on 10 or 65 (rigged). Then: what percentage of UN member states are African?
Median answer after 10: 25%. After 65: 45%.
Everyone knew the wheel had nothing to do with the question. The answers still moved twenty points. That is the unsettling part — a number you know is irrelevant still pulls.
People cannot estimate from zero. They start from whatever number is at hand and adjust — and the adjustment stops early.
Start high, stop high. Start low, stop low. Where you begin decides where you land.
Experts are not immune. Estate agents shown a "seller's asking price" before valuing a house moved their valuations toward it — and reported being uninfluenced.
Decide your own number before you look at theirs. If you have nothing written down, the first number you see becomes your starting point.
In a negotiation whoever names a figure first tends to win. When one is put to you, do not evaluate it as "reasonable or not" — ignore it and rebuild from your own reasons.
Shopping: never look at the "list price". Ask only "what would I pay for what this does?"
The struck-through price
"~~9,800~~ 3,980". Often the item was barely ever sold at 9,800. It still makes 3,980 look like 60% off. The struck-through number is not a price; it is an anchor with a line through it.
"Limit 3 per customer"
With this sign, people who wanted one buy two or three. "3" becomes the starting point and adjustment stops short of one. In field studies the sign alone raised units bought.
The first salary figure named
Name a figure first in an interview and the negotiation orbits it. Say low, settle low; say high, settle high. If you have no number ready when asked, theirs becomes the anchor.
If you take one thing
Write your own number down before you see theirs. That alone removes half the effect. An unwritten number gets overwritten by whatever you see.
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