Alakazam! The Neuroscience of Magic

It’s not every day that you see a magician mentioned in the “Acknowledgements” section of a peer-reviewed scientific paper. But last month, when the open-access journal PeerJ launched, there it was: magical act Penn & Teller got a mention both in that section of the article AND in the title.

In the paper, Stephen L. Macknick of Barrow Neurological Institute and two other researchers explore why Penn & Teller’s classic “cups and balls” magic trick works so well … by using some tricks of the cognitive-neuroscience trade. They monitored the eye movements of study participants who were watching Teller perform to understand the finer points of the illusion.

Below, you’ll see an extended version of Penn & Teller performing the age-old trick, but you can also see the videos that accompanied the paper here.

As I mention in this week’s print Newscripts, Teller had assumed “cups and balls” fools the audience—even with transparent cups—because when he picks up a cup from the table, he tilts it and causes a ball sitting on top to fall. He thought audience members were distracted by the ball’s motion and therefore didn’t notice him sliding a new ball under the cup before placing it back on the table.

Macknick and his team disproved this notion by demonstrating that viewers’ eyes didn’t stray very much from Teller’s hands when he dumped the ball. Only when he held one of the balls up or placed it on the table did he misdirect a subject’s gaze significantly.

Some Newscripts readers might at this point be scratching their heads and asking why cognitive neuroscientists are helping magicians work on their acts.

Well, Macknick told me that back in 2007, neuroscientists (a subset of them who study human consciousness) held a conference in Las Vegas. During the planning phase of the meeting, they were trying to figure out ways of drawing the public and press in, so they decided to feature magicians. After all, Macknick tells me, the tricksters are everywhere in Sin City: on the sides of buses and plastered on giant billboards. “We realized that magicians are artists of attention and awareness,” he explains. “Not only that, but they’re also better at those things than scientists.”

After the success of the conference, cognitive neuroscientists began teaming up with magicians to test theories about why illusions fool the human brain. “There are now a dozen or two labs studying magic across the world,” Macknick says. But, he adds, the magicians are putting in a lot of time and effort, “so they want science to contribute back to magic, too.”

That’s why Macknick’s team investigated “cups and balls.”

Although Teller’s intuition about the trick was incorrect, Macknick says the results of the study are still interesting. “We don’t know why, but it seems the illusion’s success might have something to do with Teller’s hands,” he says. “It could be that we’re very attracted to his hands, and that’s what draws attention.”

This phenomenon seems to hold true for another magic trick Macknick and his team have examined.  “Magicians oftentimes think social cues are an important part of misdirection,” Macknick says. For example, magician Mac King does a trick where he tosses a coin up in the air with one hand a few times and then tosses it through the air to his other hand. Except when King opens the opposite hand … no coin.

According to Macknick, that’s because King never throws the coin to begin with. He only makes it look like he tosses it (he actually palms it in his original hand). Many think the trick works partially because the magician follows the “coin” from one hand to the other with his gaze or looks at the audience. This is like looking over a person’s shoulder and saying, “What’s that behind you?” for fun. But Macknick says when he covers a magician’s face in the types of studies he conducts, participants still get flummoxed by the illusion.

“So it appears that social misdirection involving hands is much stronger than social misdirection from a magician’s gaze,” Macknick explains. “It’s not known in science whether attention to body motion is stronger than attention to gaze,” he adds, but it’s a direction his team will take in the future.


Extra links:

Macknick’s book, “Sleights of Mind”

NOVA special featuring Penn & Teller, Macknick, and other magicians

Author: Lauren Wolf

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  1. Hey Jyllian, thanks for sharing this–it’s a terrific profile. I actually did talk to Macknick a little bit about Apollo Robbins as well. As mentioned in the New Yorker piece, they published a paper together in 2011 confirming one of Robbins’ beliefs about his pickpocketing ( When he doesn’t want to steal something but wants his victim to get worried, Robbins moves his hand in a straight line from a person’s pocket. When he actually wants to steal something, he moves his hand in an arched motion. Macknick told me it likely works because of the two types of motion humans’ eyes are capable of. Pursuit eye movement (the kind that tracks an object smoothly) comes into play in the arched motion and makes for greater misdirection.

  2. And there’s more! NYTimes’s George Johnson spun a yarn about Robbins’ skills for an article about that very 2007 conference. Macknick ended up attending the Santa Fe writing workshop the same year I did, when he was still prepping his book.

  3. National Geographic’s “Brain Games” has an upcoming episode on mastering and manipulating attention: Pay Attention! Experts on the show include David Copperfield and Apollo Robbins.

    (Via Wait Wait Don’t Tell Me, which had Robbins on its show last weekend.)