Braindump

Why MBTI makes you worse at reading people

A senior director at a corporate training session asked whether they could profile luxury clients by MBTI type and adjust the sales approach — "they'd know immediately whether they're dealing with an

SourceUpdated 22 Aug 2026

Why MBTI makes you worse at reading people

A senior director at a corporate training session asked whether they could profile luxury clients by MBTI type and adjust the sales approach — "they'd know immediately whether they're dealing with an INTJ or an ENFP."

> "I felt rather like a vet being asked to examine a unicorn. You don't want to be cruel, but at some point you have to mention that the animal isn't real."

The verdict

> "One of the most successful pseudo-scientific nonsense instruments ever created" — said "with real affection for how much money it's actually made."

Developed by a mother and daughter, neither psychologists, based on having read some of Carl Jung. (Aside: "Jung himself was a bit of a nutter, but he would probably have found the whole enterprise rather reductive.")

> "The fundamental problem isn't that it's badly designed — though it is. It's that it doesn't measure stable traits." > Take it twice a few weeks apart and get a completely different type more than half the time. "In psychology, if your measuring instrument gives you a different answer every time you use it, that's not a personality test — it's a mood ring."

Why it feels accurate: the Barnum effect

Named after P.T. Barnum — "our tendency to rate vague, general personality descriptors as highly accurate when we believe they've been tailored specifically to us."

> When your profile says you're "someone who values deep thinking but also enjoys meaningful connections with others," you think "that's exactly me" — when in fact it's exactly everyone.

The descriptions are engineered to be universally flattering and just specific enough to feel personal. > "When have you ever had an MBTI or DiSC test tell you that you're actually a horrible person? You haven't."

Same mechanism as horoscopes — a comparison he notes will anger people. (He once had an online course client demand a refund and refuse to keep working with him because he criticised horoscopes.)

The genuinely useful turn — Barnum statements in luxury sales

> "This is where it gets interesting for anyone working in luxury, because we use Barnum statements constantly. We just don't call it that."

  • "You've been selected for a private viewing because of your distinctive taste."
  • "I thought of you immediately when this piece came in — it's very you."

> "That's a vague positive statement dressed up as a personal insight. And the client accepts it because it confirms something they already believe about themselves. It works spectacularly well."

> ⚠️ The stated ethical line: "Unlike MBTI, nobody in luxury is pretending that it's science. And that's the difference."

Cross-references