There is a quick test that can help you determine if you rely on intuition or reflective reasoning (intellect) when making decision. Answer the following question as quickly as possible:
“A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?”
Do you have your answer? Good. Now I want you to think about it. Commit to it. Say your answer out loud.
If you are an intuitive thinker that relies on your gut feelings, it is highly probable you answered that the ball is 10¢. You would be wrong. If you rely on reflective reasoning, or intellect, to make your decision, you probably got the answer correct.1
This was part of a study in the September 19th, online edition of The Journal of Experimental Psychology: General2. As Researcher David Rand of Harvard University said, “It’s not that one way is better than the other. Intuitions are important and reflection is important, and you want some balance of the two.” It’s a spectrum.
Different types of thinking are important in different circumstances. It’s important to be able to tap both. A parent may feel uneasy, for reasons she can’t explain, and not let her children hang around certain people. Likewise, a woman may decide not to walk down an alley alone with someone even though there is no reason for her belief. In many cases, her subconscious may have picked up on something that her intellect hasn’t yet put into concrete form. In other cases, though, those same non-reflective decisions can result in huge financial losses or mistakes.
That is the reason I’m such a fan of a mental framework that requires checklists to help defend against cognition errors. For example, had you worked the question backward, it would have been much easier to solve – as Charlie Munger says always quoting the mathematician Jacobi – “invert, always invert!”. You could have checked the accuracy of your first reaction by asking, “If a bat is $1.00 and a ball is 10¢, is the statement ‘the bat cost $1 more than the ball true?'” You would have had to simply take $1.00 – 10¢ = 90¢ to see that 90¢ is not $1. Therefore, it couldn’t be the correct answer. When in debt, work the problem backward.
1) The correct answer is 5¢. If the bat and ball together cost $1.10, and the bat has to be $1.00 more than the ball, the bat must cost $1.05 and the ball must cost 5¢ for a total of $1.10. Only then is the bat $1.00 more than the ball ($1.05 bat – 5¢ ball = $1.00 differential with the total of the two items still coming to $1.10).
2) The study was designed to test how different types of thinking influences the belief in God. The next steps will be to determine how genes and education influence thinking styles.