The Undoing Project: A Friendship That Changed Our Minds

by Michael Lewis

He suggested a new definition of the nerd: a person who knows his own mind well enough to mistrust it.

“Confirmation bias,” he’d heard this called. The human mind was just bad at seeing things it did not expect to see, and a bit too eager to see what it expected to see.

The subtle difficulties that arise when people evaluate other people had been described back in 1915 by an American psychologist named Edward Thorndike. Thorndike asked U.S. Army officers to rate their men according to some physical trait (“physique,” for example) and then assess some less tangible quality (“intelligence,” “leadership,” and so forth). He discovered that the feeling created by making the first ranking bled into the second: If an officer thought a soldier physically impressive, he also found him impressive in other ways. Switch the order of assessment, and the same problem occurred: If a person was first judged to be generally great, he was then judged to be stronger than he actually was. “Obviously a halo of general merit is extended to influence the rating for the special ability, or vice versa,” Thorndike concluded;

For his second language he picked French. The test was to translate three pages from a book in the language: The student chose the book, and the tester chose the pages to translate. Amos went to the library and dug out a French math textbook with nothing but equations in it. “It might have had the word donc in it,” said Amos’s roommate Mel Guyer. The University of Michigan declared Amos Tversky proficient in French.

“He who sees the past as surprise-free is bound to have a future full of surprises.”