Many people know who Clever Hans is. If you do not, he was the horse that could do math! Or seem to anyways. Scientists now say Clever Hans was reading body language. Any horse lover would know that most horses can “read us” whether they are just looking at us or if we are riding them. It is why horses are used for equine assisted psychotherapy. Their uncanny ability to pick up on cues from us – without us saying a word – seems almost like magic. Do you have any stories of a time when your horse “read” you or someone else? ~ HfH
From: The Nature Conservancy Blog
By: Jon Fisher
How difficult is it to overcome biases in scientific studies?
Probably more difficult than you think.
Even an honest, well-meaning scientist can come up with a study design that could strongly influence the results. My favorite example of how expectations can bias results is the story of Clever Hans the horse.
Clever Hans is not a science story, but it could well serve as a warning as we try to be unbiased on controversial issues from climate change to GMO’s.
Clever Hans’ owner gave demonstrations where he would ask the horse mathematical questions, ranging from simple arithmetic to rather complicated calculations: “If the eighth day of the month comes on a Tuesday, what is the date of the following Friday?”
Hans answered them by tapping his hoof the correct number of times.
Given that the latter question would require understanding words, grammar and even abstract concepts (like a “month”), in addition to math, people were understandably skeptical.
Psychologist Oskar Pfungst found that Hans’ real talent was in reading the unconscious cues from the person asking the question. If the questioner didn’t know the answer (a double-blind experiment), Hans didn’t either.