Final answer:
Functional fixedness is when people tend to think of an object as being useful only in the way that it is typically used. It is a type of mental set where you cannot perceive an object being used for something other than its intended purpose.
Step-by-step explanation:
When people tend to think of an object as being useful only in the way that it is typically used, they are displaying functional fixedness. Functional fixedness is a type of mental set where you cannot perceive an object being used for something other than what it was designed for. For example, if someone only sees a hammer as a tool for pounding nails and cannot think of other creative uses for it, they are demonstrating functional fixedness.