Functional fixedness also called functional fixity or functional embeddedness is a type of cognitive bias, which causes an inability to solve a problem requiring the use of a specific object, the impairment being the result of recent use of an object for a different function, or by recent perception of the object performing a different function.
The phenomenon was first described in 1935 by the German-born US psychologist Karl Duncker, who experimented with five problems, including what he called the box problem in which three small-lighted candles were to be attached to a wooden door at eye level. The subjects were presented with many objects, including a matchbox containing matches, a similar-sized cardboard box containing small candles, and a third similar box containing thumbtacks. The solution was to empty the three boxes, to fix them to the door with thumbtacks, and to stand a lighted candle in each box. While only 43 per cent of Duncker’s subjects solved the box problem in that form, 100 per cent of a control group solved it when presented with the same objects but with the three boxes empty, thus avoiding functional fixedness arising from perceiving the boxes as containers of other objects.
Across all five problems, Duncker found that the functional fixedness of crucial objects reduced the number of solutions by almost a half. Duncker pointed out that the phenomenon applies not only to physical objects or tools, but also to mental objects or concepts. An English translation from Duncker’s classic article in German was published in the journal Psychological Monographs in 1945. Functional fixedness can hamper a person’s ability to solve problems.
Functional fixedness prevents people from finding novel ways of using the objects that are familiar for solving particular problems, for solving other problems that may arise. Children who are five or younger are not fixed, they come up with new ways to use familiar objects during play. As they grow they become functionally fixed as a result of adults correcting them. By practicing creative thinking, functional fixedness can be avoided.