anchoring
Walk into a shop and see a watch tagged at 5,000 dollars, then notice a 'sale' price of 2,000. The 2,000 suddenly feels like a steal — even if 2,000 is more than the watch is really worth. The first number you saw quietly set the scale in your mind, and everything after was judged against it. That first number is an anchor, and the way it drags your estimate toward it is called anchoring.
Anchoring is the tendency to rely too heavily on the first piece of information offered (the anchor) when making a judgment, then adjusting from it — but never adjusting enough. In a famous demonstration, people spun a wheel rigged to land on 10 or 65, then guessed the percentage of African nations in the UN; those who saw 65 guessed much higher than those who saw 10, even though the wheel was obviously random and unrelated. The anchor doesn't even have to be relevant or believable to pull your number toward it.
Anchoring drives huge parts of commerce and negotiation. Sticker prices, 'was 99, now 49' tags, the first offer in a salary talk, suggested-donation amounts, and 'serving size' numbers all work by planting an anchor. Whoever names the first number often shapes the whole deal. The practical caveat: knowing about anchoring helps only a little — the bias persists even when people are warned and even among experts — so the better defense is to bring your own independent estimate before you hear the other side's number.
A menu lists a 95-dollar steak at the top. Hardly anyone orders it — but its job is to make the 45-dollar dish below it feel reasonable. The expensive 'anchor' resets what diners consider a normal price, and the restaurant sells more mid-priced plates.
The pricey item you won't order makes the next one look like a deal.
Anchoring works even when the anchor is random, irrelevant, or known to be meaningless — and even when you've been warned. Bringing your own number first is the best defense.