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Lateral thinking puzzles to test your brainpower

Lateral thinking puzzles to test your brainpower
Test your lateral thinking skills with Paul Sloane's series of brainteasers. This week, think outside of the box with a street sign puzzle

What is Lateral Thinking?

Lateral thinking is a term coined by the Maltese writer Edward de Bono.  He used it in contrast to conventional or vertical thinking. 
In conventional thinking, we go forward in a predictable, direct fashion. Lateral thinking involves coming at the problem from new directions—literally from the side. It enables us to conceive new possibilities and creative solutions to problems large and small. It is a fundamental component of innovation.
"Lateral thinking involves coming at the problem from new directions—literally from the side"
If you’re looking to challenge yourself and test your brain power, try this lateral thinking puzzle.
A man was driving down a road.  He passed a road sign saying, “Speed Limit 40.”  He drove on and came to sign saying, “Speed Limit 30.” He carried on driving and came to a sign which said, “Speed Limit 20.” He drove on and came to a sign which said, “Speed Limit 10.” What did the next sign that he came to say?
Speed limit sign
The answer is not “Stop”, “Dead End”, “Turn Around”, “School”, or anything like that.  
You have all the information you need to solve the problem, and the answer is given at the end of the article, but if you’re finding it hard to solve it’s probably because you’re making some incorrect assumptions. 

How to think outside the box

There is a story told about a northern pike, a large carnivorous freshwater fish. A pike was put into an aquarium, which had a glass partition dividing it. In the other half from the pike there were many small fish. The pike tried repeatedly to eat the fish, but each time hit the glass partition. 
Pike in a fish tank
The partition was eventually removed but the pike did not attack the little fish. It had learnt that trying to eat the little fish was futile and painful, so it stopped trying. We often suffer from this “Pike Syndrome” where an early experience conditions us into wrong assumptions about similar but different situations.
"Ask plenty of basic questions in order to discover and challenge your assumptions"
Lateral thinkers know that assumptions are there to be challenged and they relish defying them. How can you do this? Here are some tips:
  • Start by recognising that you and everyone else have ingrained assumptions about every situation
  • Ask plenty of basic questions in order to discover and challenge those assumptions
  • Write a list of all the ground rules and assumptions that apply in your environment and then go through the list and ask, “What would happen if we deliberately broke this rule?” “What if we did the opposite of the norm?"
  • Pretend you are a complete outsider and ask questions like, “Why do we do it this way at all?”

Answer to the puzzle

The next sign said, "Welcome to Speed Limit.” Most people make the quite reasonable assumption that 40, 30, 20 and 10 refer to speeds. They refer to distances from the little town of Speed Limit!
Paul Sloane is a leading speaker and best-selling author of lateral thinking and innovation books, with his new book Lateral Thinking for Every Day available to purchase on January 3rd, 2023 (Kogan Page, £12.99)
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