In an empty room are a candle, some matches, and a box of thumbtacks. The goal is to have the lit candle about five feet off the ground. You’ve tried melting some of the wax on the bottom of the candle and sticking it to the wall, but that wasn’t effective. How can you get the lit candle to be five feet off the ground without you having to hold it there?
This problem was introduced by Karl Duncker in 1945 as a cognitive performance test, and was used by Daniel T. Willingham in his article “Why Don’t Students Like School? Because the Mind Is Not Designed for Thinking” as an example of how critical thinking is hard. He claimed that the brain is not designed for thinking but designed to save you from having to think, because thinking is slow, effort-full, and uncertain.
In the candle problem, the solution is not tricky (check the solution here). However, if you don’t have enough background from similar problems it might take you a lot of time to come with the solution or you might give up thinking before solving the problem. He said that people mainly rely on memory rather than thinking. Most daily problems are ones we have solved before, so we just do what we’ve successfully done in the past and that’s known as experience. According to him, critical thinking is not a specific skill but it is a process tied to what we already know and stored in our Long-term memory. We relate what is in our Long-term memory to the current working memory to solve the problem.
An important concern he raised about students is that:
Working on problems that are at the right level of difficulty is rewarding, but working on problems that are too easy or too difficult is unpleasant.
If the student routinely gets work that is a bit too difficult, it’s little wonder that he doesn’t care much for school. Teachers should try to understand students’ feelings about problems they face for the first time like the teacher’s feeling when he hear the candle problem for the first time.
When teachers ask a question, they must WAIT for the answer. Students need time to process information! As students begin to understand, and practice the process, they WILL be able to process faster!