Friday, July 14, 2017


By nature, humans rely on intuition. Sometimes this intuition leads to a wrongful sense of overconfidence. In the second part of his novel entitled “The Lazy Controller,” Daniel Kahneman describes how our brain’s system for thinking fast and effortlessly leads us to often end up with the wrong answer to a trick question. Think about the following: 

A bat and a ball cost $1.10. The bat costs one dollar more than the ball. How much does the ball cost? 

Did you definitively say 10 cents? If you did, you’re not alone. You used your intuition to respond quickly, yet incorrectly, to this seemingly obvious word problem. If you take time to do the math and think through the solution, you will see that the true answer to this problem is 5 cents but your intuitive and automatic brain system was most likely fooled into thinking otherwise. Here are some more riddles to test how well the controlled and effortful system of your brain matches up against your automatic intuition. Good luck!


  1. I love this post! It tricked me, I was sure it was 10 cents. I am going to be trying to figure out this solution in my head for the rest of the night! Its crazy how our brains are wired and how they respond to problems. Sometimes they can lead us right to the wrong answer unless we stop to work through the problem itself.

  2. I have to admit it took be awhile to figure out why the ball cost 5 cents, my immediate answer was definitely 10 cents! I always prided myself on taking the time to think about a question before answering it but your post clearly showed me how intuition can lead to a wrong sense of overconfidence.