Warren Buffet famously quipped — “don’t ask the barber if you need a haircut.”

Want to know why?

It’s called The Law of the Instrument. Let me explain…

What is The Law of the Instrument?

The law of the instrument is a cognitive bias in which people tend to rely too heavily on the same ‘tool’ for every purpose. We have a tendency to rely on the tool that is familiar to us. Like Buffet's barber holding his or her scissors thinking you need a haircut.

When Buffet said “don’t ask the barber if you need a haircut", he elaborated:

Be careful who you ask for advice as salespeople’s job is to sell you on what they’re selling. I’ve made this mistake many times, asking the salesperson if he thinks what he’s selling is worth it. They’ll always say yes. 

Why is this interesting?

It's great to keep this law in mind when consulting any kind of specialist. The law of the instrument extends further into higher risk areas - beyond just the barber. It applies broadly when dealing with specialists of any kind.

Specialists can include doctors, lawyers, engineers, architects, mechanics and so on. Their framing, and often their incentives are not always totally aligned with yours.

I'll leave you with this quote, often attributed to 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

Want to go deeper?

🔖 Read my extended post Don't Ask the Barber if you Need a Haircut, in which I argue the merits of becoming more of a generalist in order to manage your specialist.

💎 The French have a concept called déformation professionnelle, which is our tendency to assess situations from the perspective of our profession. 

💎 Similarly, the Einstellung effect occurs when "a repeated solution to old problems is applied to a new problem even though a more appropriate response is available".

🤔 Maybe it’s most easily remembered with a little latin — caveat emptor — buyer beware.

🧠 Build your latticework! Revisit related mental models:

• The Curse of Knowledge 🎓

• The Four Stages of Competence 💡

• Regression to the Mean 🏀

• Cognitive Reframing 🖼️

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