What Body Language Actually Tells You (And What It Doesn't): The Clever Hans Lesson

Most of what you've been taught about body language is wrong.

Folded arms doesn't mean defensive. Broken eye contact doesn't mean lying. Pursed lips doesn't mean hiding something. The "X equals Y" approach to reading people — the one you'll find in airport bookstores and viral threads — is comfortable, repeatable, and dangerously misleading.

There's a better way. And a horse named Clever Hans showed us how more than a century ago.

The horse who could do math... well, or so they thought

In 1907, in Berlin, a horse named Clever Hans got famous for doing arithmetic. His owner, Wilhelm von Osten, would pose a problem — basic addition, simple multiplication, sometimes historical questions with multiple-choice answers — and Hans would stomp out the correct response with his hoof.

People assumed it was a trick. The owner must be signaling. Scientists tested it. They brought in different questioners. They changed the format. They varied the topics. Hans kept getting answers right.

It wasn't until psychologist Oskar Pfungst tried something simple that the mystery cracked open: he put a barrier between Hans and the human asking the question. Hans couldn't see the questioner's body.

His accuracy dropped to zero.

Hans wasn't doing math. He was reading micro-changes in the body of whoever was asking. When the questioner thought of the right answer, their body involuntarily reacted as Hans's hoof count approached it. A held breath. A flinch of anticipation. A small relaxation when he hit the target number. Hans wasn't smart. He was attentive.

And he was reading signals the humans didn't know they were sending.

Why the X=Y model fails

Most popular body language advice treats individual behaviors as if they have fixed meanings. Folded arms means closed off. Crossed legs means resistant. Touching the face means lying.

This is wrong for two reasons.

First, any single behavior has many possible causes. Folded arms might mean someone is cold, focused, comfortable, culturally trained to listen that way, or sitting in a chair without armrests. You don't have enough information from one behavior to know which.

Second, even a cluster of behaviors — folded arms, pursed lips, leaning back — doesn't reliably tell you what's happening. It tells you something is happening. The interpretation is yours, and most people get it wrong because they're matching what they see to a chart in their head.

The chart is the problem.

What actually works

Stop reading for meaning. Read for change.

When you're in a conversation, you're tracking a baseline. The other person's normal posture, normal breathing rate, normal eye behavior, normal hand position. The signal isn't in any of those things on their own. The signal is in the change from baseline.

When the body shifts — that's the data point. That's when something happened.

And here's the move most people miss: when you see a change, don't assign meaning to it. Get curious about it. Ask yourself a different question than the one you've been asking.

Not: What does that mean?

Instead: What did I just do? What changed for them?

That shift — from interpreter to observer — is the difference between someone who feels read and someone who feels labeled.

Labels close conversations. Curiosity opens them.

What change actually tells you

A shift in the body doesn't mean someone is lying to you. It doesn't mean they're closed off. It doesn't mean they're hiding something.

It means you have more work to do.

Maybe you need to build more rapport before this person trusts you. Maybe your language is too technical for them. Maybe you need to slow down. Maybe you've just hit something they actually care about, and this is the moment to lean in. Maybe they remembered they have to be somewhere else and it has nothing to do with you.

The change is information. It's not a verdict.

How to practice this week

Pick five conversations in the next seven days that matter to you. In each one, choose a single moment when you notice the other person's body change.

Don't try to interpret it.

Just notice it, silently, and ask yourself one question: What did I just do?

Write it down at the end of the day. Look for your own patterns — the things you do that move people closer, and the things you do that push them away.

That's how you build the skill Clever Hans had. Without the curtain.

Dr. Ed Tori is a board-certified internal medicine physician, certified hypnotherapist, and founder of Influence Everywhere. He teaches influence, communication, and behavior change to clinicians, executives, and high-performers who do good in the world. More at DrTori.com.