sign.8THOUGHT EXPERIMENT: Solve this problem: Jack is looking at Anne, but Anne is looking at George. Jack is married, but George is not. Is a married person looking at an unmarried person?

  1. A) Yes.
  2. B) No.
  3. C) Cannot be determined.

















The problem is taken from the work of Hector Levesque, a computer scientist at the University of Toronto. More than 80 percent of people choose C. But the correct answer is A. Anne is the only person whose marital status is unknown. You need to consider both possibilities, either married and unmarried, to determine whether you have enough information to draw a conclusion. If Anne is married, the answer is A: she would be the married person who is looking at an unmarried person (George). If Anne is not married, the answer is still A: in this case, Jack is the married person, and he is looking at Anne, the unmarried person.

To solve this you have to approach the problem on its own terms and think inclusively which means to consider all possibilities. Most people are educated to think exclusively which means to reduce possibilities. This kind of thinking also requires less effort. The fact that the problem does not reveal whether Anne is or is not married suggests to people that they do not have enough information, and they give the easiest inference (C).  This is an example of how easily we robotically default to the mental processes that require the least effort.


Michael Michalko




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