In a standard test of reasoning, you are given a candle, a box of thumbtacks, and a book of matches. Your task is to attach the candle to the wall so that it does not drip onto the table below.
I thought about how to melt the wax and use it to stick the candle to the wall. What would you do?
This challenge is designed to reveal functional fixedness, mental blocks against using objects in a new way. The experience that comes with age is a disadvantage here because it leads to thinking of the normal use of the box as a container for tacks. People who have never seen a tack box are less likely to have that preconception and are therefore more likely to see that the box can be emptied, tacked to the wall, and used as a support for the candle. This is why 5-year-olds do better than adults on the test. It’s also why, as a first-grader, my little brother decided to avoid clothes shopping by wearing his sweatpants backwards once there were holes in the knees.