What is the law of the instrument?

The law of the instrument refers to a cognitive bias that involves overestimating the need to use a tool in different contexts simply because it is familiar or we have the ability to use it (Kaplan, A., 1964; Maslow, A., 1966).

If all you have is a hammer, everything looks like a nail

💡 When we acquire a new skill, we tend to see opportunities to use it everywhere.

💡 This bias is also known as “the law of the hammer,” or “Maslow's hammer,” in reference to the famous quote by psychologist Abraham Maslow: “I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail.”

💡 However, the first mention of the law of the instrument is attributed to Abraham Kaplan, who mentions a similar example in his book 'The Conduct of Inquiry' (1964).

Design tip

In digital product development, teams tend to focus too much on improving the screen experience because they have this knowledge or are used to working on it. However, to create better experiences, it is more important to understand user biases and know the most impactful behavioral principles to apply than to improve screens.

Silvia Cottone

Behavioral Science Consultant & Worldwide Speaker

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Kaplan, A. (1964). The Conduct of Inquiry: Methodology for Behavioral Science. San Francisco: Chandler Publishing Co. p. 28. ISBN 9781412836296.

Maslow, A. (1966). The Psychology of Science: A Reconnaissance. South Bend, Indiana: Gateway Editions.