Florian searches for a screwdriver that is nowhere to be found. What he fails to recognize is that a coin in his pocket would easily turn the screw. This oversight best illustrates:

Functional fixedness.

Explanation:

Functional fixedness is a cognitive bias that prevents an individual from seeing that a particular object (a coin) can perform other functions in addition to its main function. Screw a screw in this case. The fixedness refers to a mental block experienced by an individual in situation in which he or she is required to solve a certain problem.

Taking the screwdriver itself as an example, it can be used to bend a soft metal object with its handle, but due to Functional fixedness, an individual would fail to see this solution.