Study: magician preparation techniques are effective in influencing choice

Choose a card, anyone. It is a staple of traditional magic tricks. But if you choose the three diamonds, the magician has probably “prepared” you to choose that card without even realizing it. This is because certain subtle verbal and gestural cues can unconsciously influence decision making, according to a recent article in the Proceedings of the National Academy of Sciences (PNAS).

There is a certain degree of well-founded skepticism around visual or verbal readiness studies. There was, for example, a famous “experiment” in 1957 by a market researcher named James McDonald Vicary, involving subliminal advertising. Vicary claimed to have conducted an experiment in which some 45,000 people attended screenings of the film. Picnic Short commercials (“Drink Coca-Cola” or “Are You Hungry? Eat Popcorn”) that lasted only 1/3000 of a second during the film were repeatedly shown at a theater in Fort Lee, NJ, thanks to a tachystoscope that Vicary said he installed in the projection booth. She reported an 18.1 percent increase in Coca-Cola sales and a surprising 57.8 percent increase in popcorn sales as a result.

The concept of subliminal advertising was later extended as a forest fire, appearing in a 1973 episode of Columbo and even incite the CIA to issue a warning report. There was only one problem: Vicary was a fraud. No one was able to reproduce those results, including Vicary himself, and Vicary eventually admitted that he had falsified his data, and the story had been a gimmick to shore up his difficult marketing business. You may never have carried out the original experiment.

While the most recent and non-fraudulent studies have suggested that priming may influence people’s choices, those studies have limitations. For example, the choices subjects can make are generally limited to two or three options, and experiments are generally performed in a strictly controlled laboratory setting, rather than a more natural, real-world setting. But there is substantial anecdotal evidence that the forcing techniques used by magicians are effective; it just hadn’t been scientifically studied. And unlike typical laboratory-tested free-choice paradigms, such techniques are subtly integrated into performance.

Alice Pailhès, a psychologist at Goldsmiths University in London and co-author of the PNAS article, is well aware of the checkered history and the long difficulty in replicating social psychology experiments on primary effects. But she is confident in using the magicians’ techniques in her own work on how unconscious factors can influence choice, as they depend on strictly controlled scripts and actions, while remaining embedded in a natural and conversational environment. She started implementing magic tricks when she was still a graduate student in France. “I love magic, and I quickly realized that magicians are the best at influencing elections,” she told Ars.

Pailhès found inspiration for his most recent research in British illusionist Derren Brown. Brown uses forcing and mental preparation techniques (among other tools) that involve verbal and visual cues in his performances, leading someone to think, for example, of the three diamond cards. (Apparently, the three of diamonds is an unlikely card for people to choose at random from a 52-card deck.)

Brown’s method involves asking an audience member to try to “mentally convey” the image of a game card, instructing the viewer to “make the color bright and vivid.” This should prompt the viewer to think of a red suit card, rather than a black suit card. Then Brown asks the audience member to imagine a screen, mimicking the shape of a diamond with his hands as he does so that the viewer thinks of the diamond suit.

To get the audience member to think of number 3, Brown asks them to imagine the “little numbers in the corner of the card and at the top.” As he does so, he quickly draws three in the air, like on an imaginary card, with his index finger. Finally, he asks the viewer to imagine the “things in the middle of the card, the boom, boom, boom, the suits” while pointing to three imaginary symbols in the air. The entire priming exercise lasts only 15 seconds.

Pailhès and his co-author, Gustav Kuhn, recruited 90 volunteers and randomized them to two groups: one group that saw a live presentation of the experiment and another that saw a videotaped version. Pailhès did the preparation herself, using Brown’s method to focus on the number of the card she wanted participants to choose (three) and the suit (diamonds). Instead of doing it in the lab, she sat at a table in the Goldsmith cafeteria, in front of the subjects, and asked them to watch her for instructions or watch a video of her delivering the same instructions on a laptop with headphones.

The participants then wrote the card they chose and rated how free and in control they felt about their choice. “The participants’ feeling of freedom is one of the key elements of a successful forcing technique,” the authors wrote. “If the magician manages to force a card, but this person feels limited and not free in his choice, the trick no longer works[s]”Those measures also allowed the researchers to assess how aware the participants were of attempts to manipulate their choice by asking them if they had noticed any gestures by the artist.”

The authors found that 17.8 percent of the subjects chose the three diamonds, while 38.9 percent chose a three (among the four suits) and 33.3 percent chose a diamond (among all the cards available in that suit). Subjects most commonly chose all three of diamonds, followed by all three of hearts. As a control, the experiment was repeated by having the participants watch a video of the same interpreter (Pailhès) and the script, minus any preparation gesture. Subjects chose the three of diamonds, or a three, significantly more often with the primer than without it, or in a random distribution. Choosing a diamond alone showed no statistically significant difference between priming, no priming, and a random distribution.

Of the subjects (16) who chose the three diamonds, only three reported that they knew the reason for their choice. Similarly, only seven of the 35 participants who chose a card out of three said they knew the reason for their choice, and even then, only three of those seven subjects specifically mentioned the artist’s gestures. Others said they chose it at random, or came up with a conspiracy to explain their choice, for example, “I always seem to count as three,” or because it was their favorite number. “Our results are consistent with the literature findings on choice blindness, illustrating that people often do not know the true reason for their choice,” the authors wrote.

“I find it surprising that so many people have no idea that I am influencing them with my gestures.”

About 72 percent of the subjects noted at least some of the grooming characteristics, but this was independent of whether or not they chose the three diamonds, and their gesture descriptions were vague. Pailhès and Kuhn found that it didn’t matter if the priming was done via live performance or video, which was contrary to their pre-experiment predictions. Pailhès was also pleasantly surprised that her prep performance really worked on so many subjects, especially since she is not a professional magician or artist at all. “I find it surprising that so many people have no idea that I am influencing them with my gestures,” she said.

Granted, a 17.8 percent success rate for getting subjects to choose all three diamonds doesn’t exactly speak to the strength of the technique; that’s why professional magicians rarely rely on priming methods alone. But it’s still significantly higher than the percentage of subjects who would randomly choose that card. Brown, according to Pailhès, is likely to have a higher success rate. He is a talented illusionist with an admitted ability to detect susceptible people, and generally performs these types of tricks in a context of reinforcing previous tricks or interactions from the audience.

According to the authors, understanding the underlying cognitive mechanism, the next step in Pailhès’ research, is important because such techniques could be used for more nefarious purposes to influence other mental processes. Previous studies, for example, have shown that subtle hand gestures and similar preparation methods can influence eyewitness testimony and even implant false memories.

“If you are a witness to a crime and then I ask you what kind of jewelry the suspect was wearing, if I’m just touching my finger, chances are good that you remember the suspect wearing a ring,” Pailhès explained. “Even if it were not true. Therefore, this could have a major impact on the criminal justice system. If you know you can be influenced in that way, perhaps you will be more careful.”

DOI: PNAS, 2020. 10.1073 / pnas.2000682117 (About DOI).