The Candle Problem From 1945 Can Only Be Solved By Creative Thinkers

To complete this silly task, you can take the tacks out of their box, tack the box onto the wall, and place the lit candle inside the box. Ta-da! Did you solve it?

Duncker noted that this problem requires participants to overcome their tendency for “functional fixedness.” He described that as a “mental block against using an object in a new way that is required to solve a problem.” In this problem, the tack box is key. Participants had a hard time seeing the box in any way other than a thing containing tacks. A variation of this problem had the tacks presented to the participants outside the box, and the participants were much more likely to figure out the tack-box-to-wall strategy. The moral of Duncker’s research? Think outside the box, literally, and don’t be too tied to the usual functions of familiar objects.