Glossary
Law of the Instrument
What is the law of the instrument?
The law of the instrument is the tendency to reach for a familiar tool or method even when it does not fit the problem. It is also known as Maslow’s hammer or the golden hammer. The phrase is a warning about mismatching methods to problems, not a universal experimental law.
Abraham Kaplan named the law in The Conduct of Inquiry (1964, pp. 28–29). It is also associated with Abraham Maslow’s observation that if your only tool is a hammer, it is tempting to treat everything as a nail. The image lasts because the mistake is familiar: expertise in one method can make a different problem look like another job for that method.
An applied example
A team skilled at writing reminder messages sees that customers are missing appointments and proposes another reminder. But suppose customers already remember the appointment and cannot attend because the booking window covers an entire day. The familiar tool addresses memory; the problem is control over time.
How to check the fit
State the problem before choosing the method. Then ask what evidence would show that the proposed tool addresses the actual obstacle. Expertise and familiar methods can be valuable. The concern is using a preferred method when it does not fit, or dismissing alternatives merely because they are unfamiliar.
Functional fixedness describes difficulty seeing new uses for a familiar object.