Try it

Max H. Bazerman and his colleagues use this exercise, adapted from psychologist P.C. Wason, to illustrate the failure to seek the right information:

The instructor writes the sequence "2-4-6" on the board and challenges students to guess the rule by calling out other sequences of three numbers. The instructor will tell them whether each sequence they offer follows the rule. Students can query as many sequences as they like, but each gets only one chance to guess the rule.

The volunteers usually offer only a few sequences before making their final guesses, and the guesses are invariably incorrect because the students have sought only evidence that would confirm their guesses. For example, one may say, "80-86-90" to confirm that the rule is "even numbers," or "1-3-5" to confirm that the rule is "numbers that go up by two." When they get that confirmation, they guess -- incorrectly.

The rule is actually "any three ascending numbers." So, Bazerman says, "it is rare that we will have answered no to a sequence." Solving this problem requires people to accumulate contradictory rather than confirming evidence -- something most of us are not good at.