Set Breaker #19: Telephone Numbers
The Set Breaker
None – you won’t find people with unlisted numbers in the phone book.
If you got it wrong, you used irrelevant information, simply because it was ‘there’.
Other stumbling blocks to problem-solving include functional fixedness (where we perceive an item only in terms of its most common use) as well as introducing unnecessary constraints (such as with the nine-dot problem below).
Connect the nine dots without lifting your pen off the paper or crossing lines.
Scroll down for answer
People often can’t accomplish this because of the self-imposed restraint – not going outside the imaginary borders or having to go through the centre of the dot.
Source: Wayne Weiten. Psychology: Themes and Variations. Brooks/Cole Publishing, 1992.