The Food Lab: Better Home Cooking Through Science

experiments. Oftentimes scientists only see what they want
to see and find the answers they want to find, even if they
don’t realize it. Have you ever heard the story of Clever
Hans the counting horse? Early in the twentieth century,
Hans made quite a name for himself by apparently being
intelligent enough to understand German, do arithmetic,
recognize the days of the week, differentiate between
musical tones, and even read and spell. His trainer would
ask him questions and Hans would respond by tapping his
hoof. For instance, when asked, “What is eight plus
twelve?” he would stamp his hoof twenty times. The horse
was a sensation, touring around Germany and amazing
crowds with his incredible abilities.
After an intensive study carried out by the German board
of education, the observers came to a shocking conclusion:
the whole thing was a scam. Turns out that Hans wasn’t able
to do any math at all. What he was quite good at was
interpreting the facial expressions and attitudes of his
trainer. As he slowly stamped his foot against the ground,
he’d observe the tension in the trainer’s face; when he
reached the correct number, the trainer would relax, Hans
would know that he was finished, and he’d stop tapping. It’s
a skill to be admired, for sure. Heck, most of my marital
problems would be solved if I could tell when my wife was
tense versus relaxed. But could the horse do math? Nope.
Yet here’s the thing: the trainer didn’t even realize what
he was doing. He thought he had an amazingly intelligent
horse. In fact, the horse was so good at reading faces that
even when a complete stranger was asking him the
questions, he would answer equally well. How did the