Clever Hans and the Ideomotor Effect

The final way that a lack of free will comes from our peculiar brains is the ideomotor effect. This phenomenon occurs when our unconscious minds transform our expectations into reality through involuntary physical reactions; we do it to ourselves, other people do it to us, and this all results in a confusing carousel wheel where it’s impossible to determine what is the true cause or reason for an act. One thing is for sure—it’s not our conscious choice.

The emphasis here is on the words “unconscious” and “involuntary.” Because we don’t know we’re causing the actions and we cannot control them, the results can be surprising—for others and for ourselves—and can even trick us into thinking there’s magic or supernatural forces at work. As one might expect, there is another, more logical explanation.

Perhaps the most famous example of the ideomotor effect at work is the story of Clever Hans. Clever Hans was a horse that many believed could perform intellectual tasks such as telling time and doing basic math, for example. During the early 1900s, the horse’s owner Wilhelm von Osten made Hans somewhat of a celebrity by carting him around Germany and showcasing his “talents” to the public. The performance would go something like this: Osten would ask the horse to calculate the sum of five plus three, and Clever Hans would tap his hoof eight times. Of course, the crowd would go wild, and von Osten would praise the horse for his superior intellect.
Not everyone believed Clever Hans was so smart, though. The German Board of Education along with psychologists Carl Stumpf and Oskar Pfungst decided to get to the bottom of the horse’s unusual behavior. They designed an experiment to determine if the horse could perform the same tasks under different circumstances. After testing Hans under many different conditions, they discovered that he answered correctly only when he could see his prompter and only when the prompter knew the answer to the question being asked.
In other words, Hans couldn’t add two plus two, but when asked by someone who could, he would tap four times, provided he could see the questioner. The researchers further surmised that the questioners would change their body language and posture as the horse was tapping out the answer. This altered stance occurred in unconscious anticipation of Hans arriving at the correct answer. The questioner would change their stance again upon the arrival of the final tap, providing a visual cue for Hans to stop. The questioners hoped Hans would answer correctly, which caused them to behave as if he would, and so he did.
Who is exercising free will in this situation? None of the human parties, anyway. The intention may match the result, but it’s a choice that is not independently made.
The ideomotor effect is similar to a self- fulfilling prophecy. You’ve probably heard Henry Ford’s famous quote, “If you think you can or if you think you can’t, you’re right.” It’s become a popular motivational saying used to encourage people to think positively so that their positive thoughts bring about positive behaviors. It may sound overly simplistic, but it actually works. (Try it!)
When you genuinely believe you can do something, you’re actually more likely to achieve the goal. The reverse is true, too. When you doubt your abilities, your abilities are automatically compromised. Keep telling yourself you’ll never get a promotion at work, for instance, and you likely never will. Self-fulfilling prophecies occur (and frequently!) because thoughts are powerful things that can indeed affect reality.
A self-fulfilling prophecy is a lot like thinking yourself into a result, good or bad. You make a prediction—or “prophecy”— about what you think is likely to happen and begin acting as if your prediction has already occurred, which in turn causes it to actually happen. For instance, consider bachelor Ted who agrees to go out on a date with Claire, a woman he believes to be way out of his league. He tells himself the date will be a disaster because Claire will immediately recognize that he’s not good enough for her. He worries about this prediction all the way to the bar, and by the time he gets there, he’s sweating bullets. He opens his mouth to greet her, and no words come out. He completely freezes, which weirds Claire out, setting the disastrous tone for the rest of the evening.
Would it have gone differently had Ted never predicted a catastrophic first date in the first place? Absolutely!
The ideomotor effect is also similar to confirmation bias, a cognitive tendency to recall or search for information that confirms something you already believe to be true. For example, if you believe everyone at your job hates you, you’ll look for instances in which coworkers respond sharply to you or supervisors criticize your work. Mentally, you’ll prove your theory— at least to yourself—that no one likes you. Everyone is susceptible to confirmation bias—even scientists—and the more powerful the belief, the more likely it is that confirmation bias will take hold.
Where the ideomotor effect differs from cognitive phenomena like self-fulfilling prophecies and confirmation bias is in its ability to cause an immediate physical reaction in addition to a cognitive one. The idea that an unconscious thought can trigger an involuntary reaction may seem disturbing, but it happens all the time.
The ideomotor effect is responsible for many people’s staunch belief in Ouija boards, for example. People who have used these boards may swear the planchette is moving on its own when really the participant is unconsciously moving it via the ideomotor effect in order to fulfill their subconscious expectations. It’s important to note that these expectations (and of course the resulting muscular movements) are not voluntary, and the participants don’t know they’re causing the movement.
Thus, when asked, they’ll report that the planchette was moving itself (or was moved by a spirit or ghost). So while Ouija boards aren’t proof that we can communicate with the dead, they are proof that our unconscious thoughts and expectations are much more powerful than we may have ever realized!
Dowsing rods work in a similar way. For centuries, pseudoscientists have claimed to be able to use rods of varying types to locate various things like oil, precious metals, and groundwater, for instance. Though they claim to have some sort of divine power, what they’re really experiencing is another unintended consequence of the ideomotor effect.
Put simply, their bodies are reacting involuntarily to the expectations in their minds regarding where something might be, causing a muscle twitch that then causes the rod to point in a particular direction. Real science has repeatedly proven the results of dowsing to be unreliable.
The ideomotor effect isn’t just the stuff of horror movies and variety shows, though. It has had many other real-world manifestations, and not all of them have been innocent. On the contrary, some have had heart-breaking and even life-ending consequences. For instance, in the case of facilitated communication, loved ones of those suffering from severe mental or physical conditions such as retardation or cerebral palsy that prohibit them from speaking have been fooled into thinking these patients can communicate with them by signaling a facilitator who then types on a keyboard.
Despite continual warnings from the American Psychological Association (APA) that facilitated communication has no scientific basis, many people still hold on to false hope that their debilitated friends and family members are really communicating with them through some medium. In many cases, people are grateful to the facilitators at first for helping them communicate with the person they love. Imagine their despair, though, when they eventually find out that it was nothing but a farce.
Then there’s the case of Brit Jim McCormick, who was convicted of fraud in 2013 for selling fake bomb detectors to countries around the world, including Iraq, Syria, and Mexico. He claimed the devices could detect bombs, even if they were very far away or buried underground. As it turns out, the gadgets did nothing at all, except act as a catalyst for the ideomotor effect. It is said that hundreds of lives were lost because of the ruse. Remember, though, in many cases—maybe even most cases—those who succeed in deceiving others with the ideomotor effect do so unwittingly and never realize the truth behind their antics.
For instance, facilitators who claim to help invalids communicate think they’re helping both the patient and his or her loved ones. They’re genuinely not trying to trick anyone; they’re simply naïve. Often, they continue to believe their own “lie” even after being proven wrong by reputable scientists over and over again. Even Wilhelm von Osten had nothing to gain by making Hans a show pony; he never charged a dime for the horse’s performances. These aren’t bad people trying to pull the wool over the world’s eyes. They’re just human beings who happen to have fallen victim to the ideomotor effect. Some people may find it disconcerting to discover just how convincing the brain can be at deception.
After all, look how foolish von Osten seems in retrospect to believe a horse could do math! And what about the spectators? How could all of those people collectively believe in something that could clearly never happen? Scary, right? There is a silver lining, though. When one is aware of how the brain operates, he or she becomes less susceptible to its trickery. In fact, the only way to outsmart the brain is to simply not trust it. Weighing subjective perceptions against cold, hard facts and concrete data is the only way to avoid being duped by our own minds and see things with any semblance of clarity.
There you have it—the ideomotor effect in action. Free will is our conscious and unfiltered intention set into action. Here, we can see that our unconscious can easily take control in ways we have zero awareness of. Whatever choice you think you are making independently is only a compendium of social and unconscious factors.

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Brain Blunders: Uncover Everyday Illusions and Fallacies, Defeat Your Flawed Thinking Habits, And Think Smarter (Or Just Less Stupidly) By Peter Hollins
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Peter Hollins is a bestselling author, human psychology researcher, and a dedicated student of the human condition. Visit to pick up your FREE human nature cheat sheet: 7 surprising psychology studies that will change the way you think.
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