If you asked Clever Hans the answer to 12 + 12, he’d tap his hoof 24 times. And if the problem was written on the chalkboard, he’d answer that, too. I had never heard of this counting horse. But during a series of two-minute mini lectures on our family Christmas Zoom call, my niece Emilie introduced us to him.
His owner, Herr Wilhelm von Osten, loved horses and taught math. In Clever Hans, he brought these two passions together. Using teaching techniques and lots of carrots and bread, von Osten taught his horse to add, subtract, multiply, and divide, to change common fractions to decimals, to understand the value of German coins, and to tell time on a watch.
And Clever Hans could spell. By tapping the alphabet—once for A, twice for B, and so on—he could stomp out words. When he saw a painting familiar to him, he could spell the name of the artist. Hearing a tune, he’d hoof off the composer. He recognized colors and playing cards and spelled out their names. And he knew the calendar of the whole year.
Von Osten took the show on the road. But not to make money. Demonstrations were free. And they were sensational, attracting attention across Germany and world-wide.

In 1904, Clever Hans appeared before the German Board of Education. After studying the horse for over a year, these educators concluded there was no hoax. Von Osten had convinced them that people didn’t give animals enough credit for their intelligence.
But then psychologists had a go at Clever Hans. They confirmed that the horse almost always gave the right answer not only when von Osten asked the question, but also when others asked. But when the horse wore blinders, something interesting happened. If Clever Hans could see the questioner, he’d get it right. If the questioner was out of sight, though, right answers dropped to six percent.
The horse, the psychologists discovered after further study, couldn’t count after all. But what Clever Hans could do was pick up the signals his questioners gave him. When he noticed a raised eyebrow or a shifting foot or a change in breathing, he could tell he was at the right answer and stopped tapping his hoof.
“Maybe Clever Hans couldn’t count,” Emilie said that day on the Zoom call. “Still, he was clever.”
After Emilie’s mini lecture I got to thinking about what we in education call the hidden curricula.
These are the lessons we teach from underlying tones.
“Trigonometry?” a guidance counselor may say with a raised eyebrow to a female signing up for classes in her junior year. And she gets the message—girls and math don’t match.
“When you go to college,” a teacher may say in a matter of fact tone to one student and not to another, even if their academic profiles are similar. And these students catch the expectation.
When I taught at a state prison, I heard a recurring statement from my inmate students, one that caused me pain each time I heard it: My teachers didn’t believe in me.
I’ve never known a teacher to say this to a student, not outright. But I take my place among the teachers who have sent powerful messages—with eyes and words and silence—that hurt rather than helped.
Students, after all, constantly look to us for cues about who they are and how to work out their lives.
Thank you, Emilie, for sending my mind this way!