Functional fixedness

Functional fixedness is a kind of problem when you can't think of more than one way to use something. It’s like if you only know how to use something for one kind of job, and you don’t realize that you can use it for other jobs too. For example, if you have a hammer and you only think of hammering nails, you’ll have a harder time solving a puzzle where you need to use the hammer to open a jar. That’s functional fixedness.