In December 2022, I traveled to Stockholm to represent Lund University in the national finals of Forskar Grand Prix. It was a privilege to be part of the contest alongside excellent researchers, and I was immensely pleased to be awarded the 1st place prize. Some folks have pointed out that using magic tricks to solicit the audience vote is somewhat akin to ‘cheating,’ which, as someone with a deep love of deception and rigged games, I embrace as compliment!
One of the biggest challenges of the format was to compress a research topic down into a four minute presentation. Personally, I think this is, in some ways, impossible. At best, there’s enough time to sketch some basic ideas and to hopefully spark enough curiosity that the audience is motivated to seek out more information. With that in mind, if you enjoyed the talk (which you can watch via the video below), and you’re interested in learning a bit more about this kind of work, you’ve come to the write place. This page is written to serve as a peak behind the curtain into some of the ideas and research that inspired my presentation.
(If you haven’t seen the talk yet, I highly recommend you give it watch before reading further.
It’s only 4 minutes, and the subsequent text contains spoilers!)
Talk Title: Let’s start with the title, ‘Seeing through illusions’ is derived directly from a book of the same name written by the psychologist Richard L. Gregory (2009). This is a delightful title because of its ambiguous DuckRabbit-esque meanings: On one hand, it can be read as referring to understanding the underlying reality beneath the deceptive surface of our subjective experiences. On the other hand, it alludes to idea that a great deal of our perceptual experience (if not all of it) is fundamentally illusory! Even when we’re experiencing ‘true’ perceptions of the world around us, those experiences are effectively constructions of our minds. Seeing Through Illusions is presently out of print, but used copies are still readily available, and I can highly recommend it. Gregory manages to cover a great deal of cross-disciplinary ground, ranging from philosophy, to psychology, to physiology, all while retaining an engaging and comfortably accessible style.
Taking Pictures: When I bring up my next slide, I ask the audience to take out their phones and snap a picture of the stage. I explain that most people believe that memory works like a camera or a recorder. This idea comes from survey research conducted by psychologists Daniel Simons and Christopher Chabris (2011; 2012). They surveyed people over the phone and online and found that there are significant discrepancies between what people believe about memory and perception, and how memory and perception actually work. Your memory does NOT work like a video camera, although sometimes it can feel as though it does. Beyond that point, I do have an ulterior motive: Later, I reveal that I (hopefully undetectably) changed shirts midway through my talk. I ask people to take a picture ‘of the stage’ so they have a visual record of my original shirt, all without me having to specifically instruct folks to attend to my clothing. True story: When I first performed that T-shirt trick on stage was at an academic conference, I’d been worried the change would be too obvious, but I ran into the opposite problem. In a room full of around 80 researchers, not only did nobody notice, but most refused believe me when I claimed that my shirt had changed! It was only because someone had happened to take a picture of me at the start of the talk that I was able convince the audience that a change even happened. So, ever since, I script that photo taking moment into the procedure.
Text and ‘Triangles’: But let’s talk about the figure itself: The image combines a pair of ‘classic’ illusions: I’ve taken a Kanizsa Triangle (Kanizsa, 1976) and embedded a written phrase into it that’s designed to evoke a proof reading illusion (e.g. Pillsbury, 1897; Sloboda, 1978). I first saw this arrangement of text in a cognitive psychology text book (Eysnyk & Keene, 2005), where it was presented as an unreferenced demo of ‘top-down’ processing. The original version reads: “Paris in the the spring,” but I like to sub in the names of the places where I’m working or speaking. Top down processing, in this case, refers our various mental preconceptions- e.g., memories, beliefs, expectations, etc. Such processes can be contrasted with with ‘bottom-up’ information from our senses- e.g. light hitting our retinas that is transduced into brain activity. Our perceptual experiences (and by extension our memories) result from a synthesis of top down and bottom up processes. The punchline here is that perceptions are not simply not simply bottom up reflections of the outside world; they’re influenced by a variety of top down mental factors. In this instance, people expect the phrase to read “Lund in the Spring,” and as a consequence they fail to notice the extra “the.” As I mention in the talk, this is fun because the extra word is not physically difficult to detect- the word is clearly printed and visible for several seconds. But, when the illusion works, top down factors are effectively overriding the the bottom up information (that typo was actually unintentional, but I’m leaving it). Such ‘proof reading errors’ present a nice practical example of top down processes in action. They’re particularly pernicious, when we’re composing our own text; we know (top down) what it is we intend to say, and this can make it very hard to detect errors in our own writing. One reason why copy-editors can be so invaluable is because they’re able to assess text with fewer preconceptions than its author. In a pinch, you can also boost your own detection rates by taking a break before proof reading your writing—‘future you’ is sort of a different person—or by forcing yourself to read your work out-loud—you can somewhat hack yourself by switching-up sensory modalities. Somewhat frustratingly, I don’t have a proper reference for the real origin of the “Paris in the the Spring” illusion- So if anyone knows of a proper original source please do get in touch!
Those illusory ‘triangles,’ in contrast, are very well documented in scientific literature. They’re an example of a Kanizsa figure, named for the Italian psychologist and artist Gaetano Kanizsa. That particular image first appeared in an article written by Kanizsa that was published in an Italian psychology journal in 1955 (an English translation by Gerino was published in 1987). They were originally presented as a thought experiment to explore the role of past experiences on perceptions. It continues to be celebrated by vision scientists as concise example of the dissociation between perception and cognition (e.g. Firestone & Scholl, 2016): Even when we know that the there are no edges to the white triangle, we still see them. Such ‘illusory contours’ have been a staple of visual cognition experiments for decades. We now know, for example, that they can even activate similar neural pathways as genuine lines (e.g. Maertens & Pollmann, 2005). For my purposes, the triangles represent a reverse form of the illusion inducing top down style processing evidenced by the “the the spring” text. Taken together, these simple illusions show how easy it is healthy sober adults to fail to perceive seemingly obvious sights or even to hallucinate images that don’t really exist. The aforementioned fact that many people believe their memories work like a video camera shows that such illusions can be deeply counter intuitive. It’s not so easy to hear in the recording, but both of these simple demos illicit gasps and explicit expressions of surprise from the audience, as if I’ve just performed a magic trick. People are often shocked that they could have failed to detect the second ‘the’ or that the edges they vividly perceive in the triangles are not really printed on the page. Hence, my third point about metacognition. These feelings of incredulity can be conceptualized as resulting from people being confronted with their own metacognitive illusions. That is to say, they demonstrate how people’s self-evaluations of their own visual experiences diverge starkly from their actual visual experience. This concept is very similar to what magicians refer to as the ‘illusion of impossibility’ (e.g. Aronson, 1990; Kuhn, 2019).
Some Practical Implications: In next slide, my aim was to use few more of my minutes explicitly argue that illusions have practical consequences beyond that simple figure (and to make a quick, probably imperceptible Arrested Development reference): Each of these four domains can (and have) filled numerous articles, books, and theses! So I’ll just take this opportunity to briefly highlight a few select bits of research.
Eye-witness testimony in courtroom settings is an excellent example of a context where illusions and metacognitive illusions can be important. One key finding from cognitive psychology is that our memories for events are ‘reconstructive’ (e.g. Loftus, 2003) that is to say, we don’t actually have the capacity to ‘instant replay’ our past experiences, even though sometimes it can feel like we can. We all know that we can forget things, but it’s not always intuitive to realize that healthy normal adults can also very easily form memories of events that never actually happened- such ‘phantom’ memories are fairly easy to induce in laboratory settings (and in the context of magic performances), which implies that they can also manifest themselves in people’s day-to-day lives. Personally, I’ve now got several well remembered incidents in my life that I now know never happened. So I know firsthand that this can be unsettling… My own feelings about the practical ramifications of eye witness testimony research have been heavily influenced by the work of Prof. Elizabeth Loftus, whose has spent decades experimentally exploring the (un)reliability of human memory and applying her expertise to real-world legal scenarios. She has a nice TED talk that provides a fairly solid introduction to her work on memory that’s viewable here. It’s also worth noting that the idea of adapting laboratory findings to legal contexts is a not at all a straightforward problem (see Otgaar, Howe, & Dodier, 2022 for a nice contemporary discussion of the complexities), but, nonetheless there’s definitely room for improvement when it comes to the way that court systems around the world apply (or fail to apply) the science of memory and perception.
Security: Understanding the differences between how perception feels like it works versus how it actually works is crucial for training security personnel to be properly vigilant for threats- to ensure they’re most likely to notice real problems and least likely to generate false alarms (e.g. Näsholm, Rohlfing, & Sauer, 2014; Muhl-Richardson et al., 2021).
Medical Screenings: Similar considerations can apply to hospital settings- for example, when radiologists need to search through scans they sometimes need to detect relatively small anomalies buried in complex visual scenes (e.g. Drew, Võ, & Wolfe, 2013).
Traffic Safety: Attention, awareness, and illusions can be very important to consider when you’re driving (super basic- don’t drive and text! Even when it feels like you’re able to do it, you’re almost certainly highly impaired). My colleague Vebjørn Ekroll recently published an excellent article where he and his co-authors compelling argue that understanding magic illusions can help us better understand traffic accidents (Ekroll et al., 2021).
This idea of magic and traffic safety nicely leads us into the closing argument of my talk. As both a researcher and a semi-professional magician, I’m a strong proponent of the ‘Science of Magic,’ an interdisciplinary endeavor wherein scholars and performers work collaboratively to better understand the principles underlying how people experience magic illusions (e.g. Lamont & Wiseman, 1999; Kuhn, Amlani, & Rensink, 2008; Macknik et al., 2008; Rensink & Kuhn, 2015; Kuhn, 2019; Tompkins, 2019). The relationship between magic and psychology can be traced back to very origins of psychology as scientific discipline- with several legendary founding fathers of psychology sought to use magic to explore the limits and eccentricities of human minds: Wilhelm Wundt (1879; Tompkins, 2017) attended seances that he publicly attributed to conjuring tricks, William James (1890) kept a Ouija board in his lab at Harvard for demonstrating the power of ideomotor illusions, Alfred Binet (1894; Thomas, Didierjean, & Nicolas, 2016) arranged for sleight-of-hand artists to have their tricks filmed in his laboratory. Despite some promising early work in the late 1800s, the concept of performance magic was largely ignored by scientists throughout the 20th century. But in these last couple decades, we’ve seen something like a Science of Magic Renaissance. Since the year 2000, there have been more than 100 new experimental papers published on the topic of magic illusions, compared to just 13 that had been published prior to 2000 (Tompkins, 2021). To be clear, this is still a relatively tiny sub-discipline; however, there is a growing appreciation amongst researchers that magic tricks can represent a powerful tool to help develop new ways of investigating human cognition. And there’s also a lovely growing community of academics and performers who are working in this area. As I mentioned at the end of my talk, my actual current job is design fake mind control machines that are designed help us study how people (mis)perceive emerging technology. If you’re interested, we recently published a paper on this topic in Consciousness and Cognition (Olson, et al. in press)- you can read the full paper here. Basically, the idea is that we can use magic illusions to simulate futuristic technologies that might be able to read people’s minds, predict their actions, or even influence their behaviors. Such technology doesn’t currently exist, but thanks to some old-school magic methods, we can make participants believe that it does. That way, we can measure our participants’ genuine behavioral responses to our fake science-fictional tech. The paradigm allows us to explore how people think (or fail to think) critically about emerging tech, and can also provide us with a sort of sneak preview as to how people might react to such tech if were to be developed. To be clear: We always ultimately reveal to people that machines are actually elaborate tricks. I look forward to sharing more of this ongoing project in the near-ish future!
Final Reveals: And finally, a few words about my talk’s ending/final reveals: One of my favorite things about studying magic is that it lends itself so well to demonstrations! Rather than simply describing illusions, I can help the audience to experience the effects for themselves. By way of illustrating how illusions can be used in more dynamic natural seeming ways, I appear to pull a red ball out of the projected slide and then make it vanish from my hands. Next, I reveal that the glasses on my face contain no lenses- they’re just empty frames, and I note that I’m wearing a different t-shirt than the one that I had on at the beginning of the talk. The glasses and the t-shirt were intended to serve as more ‘real life’ parallels to the opening figure. The illusion of lens in the glasses frames relates to the imaginary triangles. While people’s failure to spot the t-shirt swap relates to failing to notice the extra ‘the.’ When it comes to magic effects, I won’t be revealing actual performing methods, out of respect for magicians’ general reticence about exposing secrets. However, there are a few interesting things I can still tell you:
Red Ball Vanish: My method of vanishing that red ball can be traced back to at least the turn of the 20th century- and it’s probably attributable to the magician named Professor Herwin. I’m a big fan of vanishes as a research tool- in fact, my first ever academic publication (Tompkins, Woods, & Aimola-Davies, 2016) describes an experiment that involved ‘vanishing’ non-existent objects.
Illusory Lenses: The glasses bit is something of a cheap gag- but only cost me. few seconds, and I think it nicely illustrates my earlier point about how expectations can cause us to ‘see’ things that aren’t really there. I first saw the lenseless glasses reveal in a talk delivered by the legendary magician and debunker James Randi, who delivered a guest lecture at an academic conference on the psychology of consciousness back in 2007.
T-shirt Change: And, that leaves us with the t-shirt switch, which seemed to leave a strong impression on the crowd. This ‘secret’ isn’t mine to give away, and I’m indebted to the trick’s creator for coming up with such a practical robust quick change. I will tell you when the change occurs. It happens at the moment I describe how the ‘triangles’ are really just V’s and pac men shapes. Interestingly, the underlying cognitive mechanism behind this illusion was probably different for people watching me live v. watching the steam or the recording. Prior to the live streaming, I had a word with the (lovely) tech crew, and they made sure to cut away from me for a second when I make the change. So, in the stream/recording, the effect is somewhat analogous to a continuity error in film. But for the live performance, the move actually happens in plain view of the entire audience, many of whom nonetheless fail to detect the change. That second t-shirt is actually a reference to the fictional Unseen University that features in Terry Pratchett’s Discworld series. One last fun fact to hopefully distract you a bit more from the actual mechanics: The concept of a quick change act has a long weird history in magic. For some performers, like the Italian magician/quick-change artist Leopoldo Frégoli (1867-1936), the main act of their shows consisted of rapidly and inexplicably transforming their outfits. Frégoli is particularly interesting in that he’s actually been immortalized in the field of psychiatry (e.g. Langdon, Connaughton, & Coltheart, 2014): ‘The Fregoli Delusion’ is a term for a relatively rare psychiatric disorder where patients maintain a delusional (often paranoid) belief that multiple different people in their lives are really the same person wearing different disguises.
‘Apology’/Clarification Towards the end of the event, all the presenters were given the opportunity to summarize their talks. Instead of recapping the content of my presentation, I instead opted issue a pseudo-apology for my deceptions. I sought to reassure viewers that being ‘fooled’ by the illusions that I demonstrated doesn’t happens because they are foolish. Most illusions and magic tricks are accomplished by exploiting otherwise adaptive cognitive processes. Tuning out distractions and selectively forgetting elements of our environment are key mechanisms that generally help us to interact with the world around us. These processes feel effortless- so it’s easy for us to mistakenly think that we’re all naturally experts in our own cognitive functioning. But our minds are weirder than we imagine them to be (see above re metacognition). This is a really important point to me. I think a big challenge in talking about illusions is that it can be easy one of two aspects of a false dichotomy. On one hand we seem to show that people are stupid/blind/bad at thinking OR, on the other hand, to present an overly flowery idea of human minds incredible miracle machines capable of the fantastic feats of perception and consciousness. Paradoxically, I feel that both of these perspectives are true and untrue. But that complexity can be really hard to convey fluenlty, especially within a tight four minute time slot.
Thanks very much for reading- I hope this behind the scenes look was as interesting as the talk itself! Please see below for some suggestions for further reading/watching along with a list of relevant references.
The Science of Magic Association (SoMA): scienceofmagicassoc.org
I’m one of the founding members of SoMA, an interdisciplinary organization designed to promote collaboration between academics and performers who are interested in rigorous research directed toward understanding the nature, function, and underlying mechanisms of magic. We regularly hold virtual and in-person events around the world.
You can check out some recordings of our past talks/events HERE and HERE
The Spectacle of Illusion: Magic the Paranormal and the Complicity of the Mind: matt-tompkins.com/soi
I wrote a book, aimed at general audiences, on the historical and contemporary relationships between magicians and psychologists
A selectively honest account of lies about the truth about lies- with lots of weird pictures!
Experiencing the Impossible: The Science of Magic by Gustav Kuhn: mitpress.mit.edu/9780262039468/
My colleague and mentor Gustav Kuhn, has written what is probably the current definitive text on the contemporary science of magic scene. Highly recommended for anyone interested in learning more about the science of magic!
The Invisible Gorilla by Christopher Chabris and Daniel Simons: theinvisiblegorilla.com/
Simons and Chabris are the originators the iconic ‘Invisible Gorilla’ paradigm, which was, and continues to be a big influence on my own research. Their popular science book is not explicitly related to magic, per se, but is a fantastic overview of metacognitive illusions related to visual perception.
If you’re unfamiliar with the key study, HERE is a good place to start. It’s a bit more effective if you don’t have any gorilla related expectations (my apologies…) But even if you think you know what’s going to happen, I recommend watching this video to the end. And you can always get a vicarious kick out of showing it to other people who might be less familiar with the idea of inattentional blindness)
Choice Blindness Lab at Lund University: lucs.lu.se/research/choice-blindness-lab/home/
The concept of ‘choice blindness’ has always been one of my favorite examples of how magic methods can be used to advance psychological research, so it’s a real privilege to work here! (There aren’t really many institutions where I can get paid to develop fake mind control machines)
You can read about Choice Blindness HERE
And you can also watch my current boss, Petter Johansson explain and demonstrate the principle in his TED talk HERE
MAGIC Lab at Goldsmiths, University of London: magicresearchlab.com
I also maintain an affiliation with Gustav Kuhn’s Magic Lab at Goldsmiths University of London. Gustav (whose book I linked to above) is one of the pioneers of the contemporary science of magic movement, and he’s arguably the most prolific researcher in the field.
Actually one of my first job’s after obtaining my doctorate was to work as a fake psychic for Gustav, you can read about some of that work in this WIRED article
Richard Wiseman’s Quirkology Videos: youtube.com/@Quirkology/videos
Richard Wiseman’s work both researching and communicating about the science of magic has been another massive inspiration for me, personally. A great place to start is this iconic video of ‘The Colour Changing Card Trick’
References:
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Binet, A. (1894). Psychology of prestidigitation. Annual Report of the Board of Regents of the Smithsonian Institution (pp.555–571). Washington, DC: Government Printing Office.
Drew, T., Võ, M. L. H., & Wolfe, J. M. (2013). The invisible gorilla strikes again: Sustained inattentional blindness in expert observers. Psychological science, 24(9), 1848-1853.
Ekroll, V., Svalebjørg, M., Pirrone, A., Böhm, G., Jentschke, S., van Lier, R., Wagemans, J. & Høye, A. (2021). The illusion of absence: how a common feature of magic shows can explain a class of road accidents. Cognitive research: principles and implications, 6(1), 1-16.
Eysenck, Michael; Keane, Mark (2005). Cognitive Psychology: A Student's Handbook (5th ed.). Taylor & Francis. p. 2.
Firestone, C., & Scholl, B. J. (2016). Cognition does not affect perception: Evaluating the evidence for “top-down” effects. Behavioral and brain sciences, 39.
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Gregory, R. L. (2009). Seeing through illusions. Oxford University Press.
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Kanizsa, G, (1955). Margini quasi-percettivi in campi con stimolazione omogenea. Rivista di Psicologia 49: 7-30.
Kanizsa, G. (1987). Quasi-perceptual margins in homogeneously stimulated fields (W. Gerbino, Trans.). In S. Petry & G. E. Meyer (Eds.), The perception of illusory contours (pp. 40–49). New York, NY: Springer. (Original work published 1955)
Kuhn, G. (2019). Experiencing the impossible: The science of magic. Mit Press.
Kuhn, G., Amlani, A. A., & Rensink, R. A. (2008). Towards a science of magic. Trends in cognitive sciences, 12(9), 349-354.
Lamont, P. (2010). The misdirected quest. Psychologist, 23(12), 978-980.
Langdon, R., Connaughton, E., & Coltheart, M. (2014). The Fregoli delusion: a disorder of person identification and tracking. Topics in cognitive science, 6(4), 615-631.
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Macknik, S. L., King, M., Randi, J., Robbins, A., Thompson, J., & Martinez-Conde, S. (2008). Attention and awareness in stage magic: turning tricks into research. Nature Reviews Neuroscience, 9(11), 871-879.
Maertens, M., & Pollmann, S. (2005). fMRI reveals a common neural substrate of illusory and real contours in V1 after perceptual learning. Journal of cognitive neuroscience, 17, 1553-1564.
Muhl-Richardson, A., Parker, M. G., Recio, S. A., Tortosa-Molina, M., Daffron, J. L., & Davis, G. J. (2021). Improved X-ray baggage screening sensitivity with ‘targetless’ search training. Cognitive research: principles and implications, 6(1), 1-20.
Näsholm, E., Rohlfing, S., & Sauer, J. D. (2014). Pirate stealth or inattentional blindness? The effects of target relevance and sustained attention on security monitoring for experienced and naïve operators. PLoS One, 9(1), e86157.
Olson, J. A., Cyr, M., Artenie, D. Z., Strandberg, T., Hall, L., Tompkins, M. L., ... & Johansson, P. (2023). Emulating future neurotechnology using magic. Consciousness and Cognition, 107, 103450.
Otgaar, H., Howe, M. L., & Dodier, O. (2022). What can expert witnesses reliably say about memory in the courtroom?. Forensic science international: mind and law, 3, 100106.
Randi, J. (2007, June 24). Implying data that isn’t there: Or how an audience can be lulled into eagerly accepting suggestions and unspoken information. Association for the Scientific Study of Consciousness 11th Annual Meeting, Las Vegas, NV, USA.
Rensink, R. A., & Kuhn, G. (2015). A framework for using magic to study the mind. Frontiers in psychology, 5, 1508.
Thomas, C., Didierjean, A., & Nicolas, S. (2016). Scientific study of magic: Binet’s pioneering approach based on observations and chronophotography. The American Journal of Psychology, 129(3), 313-326.
Tompkins, M. L. (2021). A Science of Magic Bibliography. https://www.matt-tompkins.com/blog/2021/3/29/a-science-of-magic-bibliography-2021-update
Tompkins, M. L. (2017, June). Blinded by séance: The man who offered scientists an afterlife. New Scientist, 3130, pp. 42-43. https://www.newscientist.com/article/mg23431300-800-blinded-by-seance-the-man-who-offered-scientists-an-afterlife/
Tompkins, M. L. (2019). The Spectacle of Illusion: Magic, the paranormal & the complicity of the mind. London: Thames & Hudson. ISBN: 978-1-942884-37-8
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