Blaming the Horse
It is curious that ethologists looked down on animal cognition and emotions as too speculative, while feeling on safe ground with behavioral evolution. If there is one area rife with conjecture, it is how behavior evolved. Ideally, you’d first establish the behavior’s heredity and then measure its impact on survival and reproduction over multiple generations. But we rarely get anywhere close to having this information. With fast-breeding organisms, such as slime molds or fruit flies, these questions may be answerable, but evolutionary accounts of elephant behavior, or human behavior for that matter, remain largely hypothetical since these species don’t permit large-scale breeding experiments. While we do have ways of testing hypotheses and mathematically modeling the consequences of behavior, the evidence is largely indirect. Birth control, technology, and medical care make our own species an almost hopeless test case for evolutionary ideas, which is why we have a plethora of speculations about what happened in the Environment of Evolutionary Adaptedness (EEA). This refers to the living conditions of our hunter-gatherer ancestors, about which we obviously have incomplete knowledge.
In contrast, cognition research deals with processes in real time. Even though we cannot actually “see” cognition, we are able to design experiments that help us deduce how it works while eliminating alternative accounts. In this regard, it really isn’t different from any other scientific endeavor. Nevertheless, the study of animal cognition is still often considered a soft science, and until recently young scientists were advised away from such a tricky topic. “Wait until you have tenure,” some older professors would say. The skepticism goes all the way back to the curious case of a German horse named Hans, who lived around the time Morgan crafted his canon. Hans became its proof positive. The black stallion was known in German as Kluger Hans, translated as Clever Hans, since he seemed to excel at addition and subtraction. His owner would ask him to multiply four by three, and Hans would happily tap his hoof twelve times. He could also tell you what the date of a given weekday was if he knew the date of an earlier day, and he could tell the square root of sixteen by tapping four times. Hans solved problems he had never heard before. People were flabbergasted, and the stallion became an international sensation.
Clever Hans was a German horse that drew admiring crowds about a century ago. He seemed to excel at arithmetic, such as addition and multiplication. A more careful examination revealed, however, that his main talent was the reading of human body language. He succeeded only if he could see someone who knew the answer.
That is, until Oskar Pfungst, a German psychologist, investigated the horse’s abilities. Pfungst had noticed that Hans was successful only if his owner knew the answer and was visible to the horse. If the owner or any other questioner stood behind a curtain while posing their question, the horse failed. It was a frustrating experiment for Hans, who would bite Pfungst if he got too many answers wrong. Apparently, the way he got them right is that the owner would subtly shift his position or straighten his back the moment Hans reached the correct number of taps. The questioner would be tense in face and posture until the horse reached the answer, at which point he would relax. Hans was very good at picking up these cues. The owner also wore a hat with a wide brim, which would be down as long as he looked at Hans’s tapping hoof and go up when Hans reached the right number. Pfungst demonstrated that anyone wearing such a hat could get any number out of the horse by lowering and then raising his head.22
Some spoke of a hoax, but the owner was unaware that he was cuing his horse, so there was no fraud involved. Even once the owner knew, he found it nearly impossible to suppress his signals. In fact, following the report by Pfungst, the owner was so disappointed that he accused the horse of treachery and wanted him to spend the rest of his life pulling hearses as punishment. Instead of being mad at himself, he blamed his horse! Luckily for Hans, he ended up with a new owner who admired his abilities and tested them further. This was the right spirit, because instead of looking at the whole affair as a downgrading of animal intelligence, it proved incredible sensitivity. Hans’s talent at arithmetic may have been flawed, but his understanding of human body language was outstanding.23
As an Orlov Trotter stallion, Hans appears to have perfectly fit the description of this Russian breed: “Possessed of amazing intelligence, they learn quickly and remember easily with few repetitions. There is often an uncanny understanding of what is wanted and needed of them at any given time. Bred to love people, they bond very tightly to their owners.”24
Instead of being a disaster for animal cognition studies, the horse’s exposé proved a blessing in disguise. Awareness of the Clever Hans Effect, as it became known, has greatly improved animal testing. By illustrating the power of blind procedures, Pfungst paved the way for cognitive studies that were able to withstand scrutiny. Ironically, this lesson is often ignored in research on humans. Young children are typically presented with cognitive tasks while sitting on their mothers’ laps. The assumption is that mothers are like furniture, but every mother wants her child to succeed, and nothing guarantees that her body movements, sighs, and nudges don’t cue her child. Thanks to Clever Hans, the study of animal cognition is now more rigorous than that. Dog labs test the cognition of their animals while the human owner is blindfolded or stands in a corner while facing away. In one well-known study, in which Rico, a border collie, recognized more than two hundred words for different toys, the owner would ask for a specific toy located in a different room. This prevented the owner from looking at the toy and unconsciously guiding the dog’s attention. Rico would need to run to the other room to fetch the mentioned item, which is how the Clever Hans Effect was avoided.25
We owe Pfungst a profound debt for demonstrating that humans and animals develop communication that they are unaware of. The horse reinforced behavior in his owner, and the owner in his horse, whereas everyone was convinced that they were doing something else entirely. While the realization of what was going on moved the historical pendulum to swing firmly from rich to lean interpretations of animal intelligence—where it unfortunately got stuck for too long—other appeals to simplicity have fared less well. Below I describe two examples, one concerning self-awareness and the other culture, both concepts that, whenever mentioned in relation to animals, still send some scholars through the roof.
Armchair Primatology