Most magic tricks require a fairly sophisticated understanding of how humans perceive the world. To fall for a trick, people have to see things they perceive as important and ignore things that are actually important. Understanding why magic works can tell us important things about how humans direct their attention and form expectations.
At some point, behavioral scientists realized they could take this idea and apply it to animals. If animals are also fooled by magic tricks, we can identify where our cognitive skills overlap. If the trick fails, we can identify points where our understandings of the world diverge. Unsurprisingly, most early experiments were done with other primates, as they would likely have a lot of overlap with us. But a new study attempts magic with birds and finds that many tricks just don’t work with them.
Not easily fooled
The birds in the study were Eurasian jays, who are part of a family (corvids) known to be unusually intelligent. Many species of jays cache food (if you’ve ever found that oak trees have been seeded in your flower pots, jays are probably why) and often engage in elaborate deceptions to keep their fellow jays from stealing their caches. So it’s not a stretch to think that magic might be something birds could comprehend.
But unlike humans, birds aren’t likely to be interested in what happens to coins or cards. So the researchers instead performed magic tricks with worms, which the birds were definitely interested in. Overall, the researchers tried three different tricks. One was the French drop, in which the audience is convinced that the performer has moved an object to a new hand when it’s actually retained in the original hand. The palm-to-palm transfer operates similarly—the object appears to be transferred but isn’t.
Another trick involved hand motions that obscured what was happening—and then an actual transfer of a worm to the opposite hand. Rather than relying on misdirection, this trick required that the actions take place too quickly for anyone (or any bird) to follow where the worm ended up.
The researchers got good enough at the tricks that they could consistently fool humans. Out of 160 tests for each trick, humans were typically misled by the magic. They chose the wrong hand after the palm transfer 115 times out of 160 tests; they got the French drop wrong 120 times; and they missed the fast pass 140 times. Slowing the process down so people had a better chance to see what was going on allowed almost all the humans to pick the correct hand.
Not so with the birds. Results for the palm transfer were confusing. Humans did well both on the slow transfer, where they could see what was going on, and on the control, where the worm was actually transferred. The birds did the worst on the control and did somewhat better when the worm was retained in the original hand (the magic condition)—and better still when the trick was performed slowly.
For the French Drop, the conditions didn’t matter; the birds consistently guessed the correct hand. And for the fast pass, where the worm does change hands, the birds weren’t fooled at all. But they were often confused by the control experiment, in which the worm was retained in the original hand. This fact turned out to be important. The researchers only had six birds, so some of the corvids’ good performance may have come from learning where to expect the food. But in this control, the birds got it wrong 86 percent of the time, indicating that any learning of this sort is pretty limited.
Well, that’s different
Overall, the results were pretty confusing, with the birds’ worst performance coming in the control experiments in two of the three cases. But one thing is clear: in the magic situation, where most humans got things wrong, the birds consistently guessed the right hand more often than not. And that’s enough to tell us that their perception is quite different from ours.
The researchers suggest that one explanation is that the birds’ perception is physically different, with the location of their eyes ensuring that only a small part of their visual field can receive input from both eyes. It’s possible that different levels of depth perception can explain some of the variation or why some magic tricks were more confusing than others.
The other issue the authors mentioned is a matter of human anatomy. The magic portion involves subtle actions with hands, and birds don’t typically have to watch hands that closely. While these birds were raised in captivity and had more experience with human anatomy, that may not have been enough to help them recognize the sorts of misdirections used in the experiments.
Finally, there’s the whole issue of what knowing how to deceive others—which jays clearly do—means for being able to recognize when you are being fooled. There’s no way to get inside a bird’s mind to figure out what sort of mental model allows it to manage perception, so it’s impossible to know if that model is flexible enough to recognize deception in other contexts.
The simple experiments the researchers performed can’t address any of these more complicated questions. But they do suggest that there’s something interesting enough here that getting more data will be worthwhile.
PNAS, 2021. DOI: 10.1073/pnas.2026106118 (About DOIs).