Clever Hans, the "Psychic" Horse
by D. Trull
Enigma Editor
Who is the smartest horse of all time? Mr. Ed? Trigger? Silver? Secretariat? No offense to these
formidable equine I.Q.'s, but the clear winner, hooves down, would have to be Clever Hans.
Never heard of him? That's a shame, because this horse was so amazingly brilliant, he was able to
convince teams of scientists that he was psychic.
Clever Hans lived in Germany back in the early 1900s. His owner, Wilhelm von Osten, claimed that his
horse was smart enough to answer a wide variety of questions, such as solving math problems, telling
time, and giving the names of people he knew. Clever Hans communicated by encoding the alphabet
into hoof-taps: one tap meant "A," two taps meant "B," and so forth.
Prominent German scientists tested Clever Hans until most were convinced that the horse's highly
accurate responses were not the result of trickery. The horse performed "almost as well" when von
Osten was absent as when the master was present.
But researchers were not unanimous in pronouncing Clever Hans a bona-fide horse prodigy. Scientist
Oskar Pfungst uncovered Hans's one weakness: he was unable to respond correctly when no one in
front of him knew the answer to the question at hand.
Was Clever Hans being secretly cued by someone other than von Osten? Apparently so... but further
tests showed that no one was tipping off Clever Hans intentionally -- he simply needed someone in the
know to BE there! Those scientists of a less skeptical bent than Pfungst had reason to wonder if Clever
Hans wasn't so much an intellectual giant as he was a mind reader.
In the end, Clever Hans's observers arrived at a scientific explanation, one that involves neither
superintelligence or telepathy, but is still astonishing. They decided that Hans possessed an uncanny
perception of involuntary physical responses in humans. He had learned to identify subtle tensing and
relaxing of muscles that occur in someone who is anticipating the correct answer. Thus, Hans would tap
his hoof until he saw the subconscious twitch in observers who knew he had arrived at the right spot in
the alphabet, and there Hans would stop, oblivious to the semantic content of his actions.
Pretty cool horse, huh? And a pretty airtight wrap-up, too, except for one thing that still bothers me. Did
anyone consider the difficulty of fluently communicating via the tap-alphabet? Could I talk like Clever
Hans without me and you both getting desperately lost and confused?
Tap, tap, tap, tap, tap, tap, tap, tap.
Tap, tap, tap, tap, tap.
Tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap.
Tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap.
Tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap.
Tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap, tap!