The psychology behind magic: how magicians sway decision-making

I once was tricked by a street magician and wondered how he did it. A team of Canadian researchers has now combined the art of magic and the science of psychology to demonstrate how certain contextual factors can sway the decisions people make, even though they may feel that they are choosing freely. And it explains quite a lot to me… and their findings can even have potential implications for understanding our daily decision-making that maybe less based on free will than one might think.

In short:


  • The researchers examined how magicians subtly influence audience’s decisions.
  • A magician flipped through a deck of cards while participants chose a card.
  • The magician influenced their choice almost every time without them noticing.
  • Properties of the cards and participants’ personalities predicted card choice.
  • They combined real-world and laboratory studies to examine magic.


From the press release:

“We began with a principle of magic that we didn’t fully understand: how magicians influence audiences to choose a particular card without their awareness,” explains Jay Olson, lead author of a new study published in Consciousness and Cognition. “We found that people tend to choose options that are more salient or attention-grabbing, but they don’t know why they chose them,” says Olson, a graduate student in psychiatry in McGill University’s Raz Lab, which investigates psychological phenomena such as attention and consciousness.

The research was conducted in two stages. In the first, Olson (who is also a professional magician) approached 118 people on streets and university campuses and asked them to choose a card by glancing at one as he flipped through a deck of playing cards. The entire riffle took around half a second, but Olson used a technique to make one of the cards — the “target card” — more prominent than the rest. Some 98% of participants chose the target card; but nine in 10 reported feeling they had a free choice. Many concocted explanations for their decisions: one, for example, claimed she chose the target card (the 10 of Hearts) because “hearts are a common symbol and the red stood out.”

Btw, this is the trick:

In the second stage, the researchers created a simple computer-based version of the riffle by presenting a series of 26 images of cards sequentially on a screen. Researchers asked participants to silently choose a card, then enter it after each of 28 different trials. Overall, participants chose the target card on 30% of the trials. Although “reasonably high” this rate was much lower than in the first study, “possibly because many of the social and situational factors central to magic tricks were absent” from the conventional laboratory conditions in which this stage was carried out, says co-author Ronald Rensink, a professor of psychology and computer science at the University of British Columbia. In a magic performance, for instance, spectators may be influenced by the personality of the magician, expectations created by the setup, and pressure to choose a card quickly, he notes.

“Magic provides an unusual lens to examine and unravel behaviour and the processing of higher brain functions,” says co-author Amir Raz, who is a former professional magician and holds the Canada Research Chair in the Cognitive Neuroscience of Attention in McGill’s Faculty of Medicine. “This study joins a nascent wave of experiments that binds the magical arts to the principles of psychological and neural sciences. Such a marriage has the potential to elucidate fundamental aspects of behavioural science as well as advance the art of conjuring.”

Of course the combination of magic, psychology and research is nothing new if you know Richard Wiseman.

Abstract of the study:

Forcing occurs when a magician influences the audience’s decisions without their awareness. To investigate the mechanisms behind this effect, we examined several stimulus and personality predictors. In Study 1, a magician flipped through a deck of playing cards while participants were asked to choose one. Although the magician could influence the choice almost every time (98%), relatively few (9%) noticed this influence. In Study 2, participants observed rapid series of cards on a computer, with one target card shown longer than the rest. We expected people would tend to choose this card without noticing that it was shown longest. Both stimulus and personality factors predicted the choice of card, depending on whether the influence was noticed. These results show that combining real-world and laboratory research can be a powerful way to study magic and can provide new methods to study the feeling of free will.

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