Atlas · 02 / 02
A number, and a date
You have to name a year you do not know. Where does your mind start?
Two rounds, three short questions.
Before the question, a small piece of arithmetic.
Take the last three digits of your phone number and add 400 to them.
Nothing you type here leaves your browser.
Attila led the Huns across the Roman world, from the Balkans into Gaul, for about twenty years.
Eventually his campaigns in Europe were brought to a halt.
One more thing before the answer.
Almost nobody knows this date. The question is how wide your not knowing is.
This page asks you to build a number out of your own phone number, and then asks when Attila's campaigns in Europe ended.
The two have nothing to do with each other.
Participants whose number comes out low guess earlier years. Those whose number comes out high guess later ones.
629average guess in the demonstration Marcus reports, from participants whose anchor came out below 600
979average guess in the demonstration Marcus reports, from participants whose anchor came out between 1,200 and 1,399
Gary Marcus, Kluge, 2008, p. 47.
Anchoring
You end up close to wherever your mind started.
Why this happens
You did not guess badly. Hardly anyone knows this date, and holding a range two or three centuries wide is an honest description of not knowing.
Nor does one answer prove anything about you. What you just did is a single run with nothing to compare it against; the two numbers above are the evidence, because they come from many participants split by nothing but their own phone numbers.
The effect has two shapes, and both are the same fault. One is a number you came up with yourself, and that is what just happened to you: you set off from it and stop at the first answer you can live with. There is a moment of adjusting, and it rarely goes far enough. The other is a number somebody hands you. That one is quicker. It does not start a search, it decides what comes to mind first, so there is no moment of adjusting for you to catch. Everything in the list below, and the closing round after it, is that second kind.
What a number like that changes is not what you know. It changes where the search begins. With a figure already in mind, most people set off from it and stop once a year feels acceptable.
Starting low, the first acceptable year is near the bottom of your range. Starting high, it is near the top. The middle, which is usually the better guess, is the one place the search never ends, because you always reach something plausible before you get there.
Knowing where the number came from does not protect most people from it. That is what Marcus means by a kluge: the mind adjusts from wherever it happens to be standing, because it never evolved any way to start from nowhere.
As for 451: that is the year Attila's army was beaten in Gaul, on the Catalaunian Plains. He rode into Italy the following year and died the year after that, so if you said 452 you were not exactly wrong. The question is Marcus's, and so is the answer he gives for it.
Now that you know
Same experiment. This time nothing is hidden.
This one runs the other kind: the number does not come from you, you are handed one.
The river Danube runs from the Black Forest to the Black Sea, through ten countries.
In the wild
In each of the six examples below, someone else supplied the number.
Retail
$200
price
A tray of necklaces sat unsold at $100. Priced at $200 by mistake, they were gone by the time the owner was back from holiday. The higher number became what the necklaces looked like they were worth.
Cialdini, reported in Kluge p. 80
Public safety
£25
payment ceiling
People were asked what they would pay each year for the same reduction in road deaths, and pushed until they refused. Started at £25, they stopped at £149 on average. Started at £75, they stopped at £232.
Jones-Lee & Loomes, reported in Kluge p. 80
Supermarkets
LIMIT 12
purchase limit
A sign capping purchases at twelve tins sent shoppers home with about twice as many as a sign capping them at four. The cap was never the point; the number was.
Wansink, Kent & Hoch, 1998
Hiring
€55–65k
posted band
The band printed in the post decides where the conversation starts. Most people end up asking for a figure inside it, rather than the one they walked in with.
everyday observation, no citation
Tipping
25%
suggestion
Card readers put their largest suggestion on the left. Even the people who reject all three and tap Custom type a number pulled toward the ones they just saw.
everyday observation, no citation
Discounts
$120
struck-through price
The crossed-out price is not what anything ever cost. It is there to be the number you compare $79 against.
References
- Marcus, G. (2008)· cited aboveKluge: The Haphazard Construction of the Human Mind. Houghton Mifflin
- Tversky, A. & Kahneman, D. (1974)Judgment under uncertainty: heuristics and biases. Science 185(4157), 1124–1131
- Wilson, T. D., Houston, C. E., Etling, K. M. & Brekke, N. (1996)A new look at anchoring effects: basic anchoring and its antecedents. Journal of Experimental Psychology: General 125(4), 387–402
- Epley, N. & Gilovich, T. (2006)The anchoring-and-adjustment heuristic: why the adjustments are insufficient. Psychological Science 17(4), 311–318
Which of these is an anchor?
Four things you might read tomorrow. In each case, would it be the number the next figure gets measured against?
The seller's opening list price in a shop window.
The manufacturing cost of the product on the shelf.
The salary band printed at the top of a job posting.
The number of months of experience the posting asks for.
Where this shows up again
A salary negotiation opens with one whenever the recruiter names a figure first. So does a tipping screen with 15, 20, 25 already lit up, a "was 129, now 79" tag on a shirt, or the opening bid on a house.
None of these numbers pretends to be neutral, and there is rarely much else to compare them against. Whichever one is nearest becomes the reference, and most of the time it was picked by someone else.
The same wordless move underlies Framing Effect, where the number itself does not shift, only the zero it is measured from.
One sentence to walk away with
The mind does not start from nothing. It sets off from whatever number is nearest, and stops at the first place it can live with.