No play required. The ways human judgment drifts, and questions with no answer, with everyday examples
The directions human judgment reliably drifts
Peter Wason, 1960
People go looking for proof they are right and never for proof they are wrong. The first page of search results, and you are sure.
Dunning and Kruger, 1999
The less skilled you are, the more you overrate yourself. Famous — and the "mountain" chart everyone shares is not in the paper.
Tversky and Kahneman, 1974
The first number you see drags every judgment after it. The whole mechanism of "was 9,800, now 3,980".
Johnson and Goldstein, 2003
Whatever is pre-selected stays selected. The newsletter checkbox that came ticked.
Kahneman, Knetsch and Thaler, 1990
What you own looks worth more than it did before you owned it. The same mug doubles in price the moment it is yours.
Bertram Forer, 1949
A description that fits everyone feels like it was written about you. Yes, the quizzes on this site ride on it too.
Abraham Wald, 1943
Looking at the bullet holes on planes that came back and armouring those spots is wrong. Nobody gets to interview the planes that did not.
Bluma Zeigarnik, 1927
Unfinished things stick in your head more than finished ones. Why "to be continued" works and why drafts will not close.
Robert Zajonc, 1968
Seeing something repeatedly is enough to make you like it. Why the song that sounded odd at first is good by the third listen.
Kahneman and colleagues, 1993
You remember an experience by its most intense moment and its ending. Length barely counts. Why the last day of a trip decides the whole trip.
Where the Dopa Dilemmas come from. Questions without answers
Ancient Greece, via Plutarch
Replace the planks one at a time. When none of the original is left, is it the same ship? This is the sauce-pot problem.
Robert Nozick, 1974
A machine that gives you any experience you want, for as long as you want. None of it real. Do you plug in?
Walter Mischel, around 1970
One now, or two in fifteen minutes. The famous follow-up shrank a lot when people checked.
Güth and colleagues, 1982
They choose the split; you only accept or refuse. Refuse and you both get nothing. People refuse anyway.
Fourteenth century
Two identical bales, no reason to prefer either, and the donkey starves. The same shape as failing to pick a lunch place.
Arkes and Blumer, 1985
Money and time you cannot get back bend the next decision. Yes, sitting through the bad film.
Iyengar and Lepper, 2000
The 24-flavour table drew the crowd; the 6-flavour table made the sales. Too much choice stops the choosing.
Flood and Dresher, 1950
Both stay quiet and both do well. Selling out pays better, so both sell and both lose.
Tversky and Kahneman, 1981
"90% survive" and "10% die" are the same number. They do not get chosen the same way.
Derek Parfit, 1984
It scans you here and builds you there. Is the one who steps out you?