The spa is busy today. Employees bustle about with towels and cleaning supplies, women walk carefully, with freshly pedicured feet. You have an agenda today, as well - a relaxing spell in the hot sauna before you head home for the night. You make your way through the crowded locker room, over to the steamy double doors, and you push your way through, into a cloud of hot fog.
Lying on the floor of the sauna is a man, face down on the tile floor.
The man has died of what appears to be a stab wound to the back. There is one other man in the sauna with you, and it becomes clear that this is the man who has committed the crime. He has blood on his hands, and on the thermos he carried into the sauna with him. However, the man has no weapons on or around his body. Since you know that the man in the room is guilty, how can you prove his guilt? How did he manage to kill the man in the sauna and get rid of the weapon, all without leaving the sauna and before anyone else discovered the body?
This question, written by the authors of the game Mind Trap, stumps almost everyone. In reality, the answer to the question is actually quite simple; why, then, do most people have a hard time answering this riddle?
In writing this question, the authors of Mind Trap are exploiting a very common cognitive bias- functional fixedness. Functional fixedness limits a person to using an object only in the way it is traditionally used. This concept originated in Gestalt Psychology, a movement that emphasizes holistic processing, or considering a situation and all it's components as a whole. For example, a person experiencing functional fixedness may not consider a hammer to be useful for anything except for pounding nails. Similarly, we may not immediately think that a thermos can be used to house something solid - like ice - or that icicles can be used in a similar fashion to knives and other sharp objects, rather than just for cooling drinks.
Aaaah. So that's how he did it.
One thing I found really interesting about functional fixedness is that children under the age of five often exhibit no signs of this cognitive block (according to various studies). This is because these children often think more about the problem than about the fact that the problem must be solved with a particular object. So, they may ponder how they can make two pieces of wood stick together, rather than the fact that regularly, people use a hammer and nails to make the two pieces of wood stick together. However, by age 7, most kids have acquired functional fixedness. This is according to a study done in 2000 by German & Defeyter. Check out this link for a little more info:
Is there any way to combat functional fixedness? It seems that if we keep this concept in mind when problem solving, it is easy to work around it consciously. However, if anyone knows a little more about functional fixedness and who it affects, I'd love to hear some comments! Thanks!