Exploring the perceptual inabilities of Eurasian jays (Garrulus glandarius) using magic effects

A special issue in honor of the contributions of Professor Nicola S. Clayton FRS

It has been an honor to edit this special issue of Learning & Behavior to recognize the exceptional contributions of Prof. Nicky S. Clayton FRS to the fields of comparative cognition and developmental and experimental psychology. Prof. Clayton has also provided supervision, mentorship, and support for many students, researchers, and colleagues throughout her career, including over 52 PhD candidates and postdoctoral researchers, helping to pave the way for a generation of future scientists in academia and industry. Indeed, all four of the co-editors on this special issue worked with Prof. Clayton in her Cambridge University Comparative Cognition Lab as PhD candidates and/or postdoctoral researchers (from 2011 to 2022), and we happily continue to collaborate together. Prof. Clayton was awarded the 2024 Comparative Cognition Society (CCS) Research Award and delivered the Master Lecture at the 31st International Conference on Comparative Cognition (CO3, April 2024). Dr. Rachael Miller and Prof. Joshua Plotnik (co-editors) co-organized a symposium at the CO3 conference dedicated to Prof. Clayton. The invited symposium speakers were Prof. Mike Beran (Georgia State University), Prof. Jon Crystal (Indiana University), Dr. Christelle Jozet-Alves (Université de Caen Normandie), and Prof. Thomas Bugnyar (University of Vienna). Dr Elias Garcia-Pelegrin (co-editor) served as Master of Ceremony for an evening CO3 banquet, which included a video compilation of "thank you" messages from many of Prof. Clayton's colleagues, students, and friends.

There's "magic" in comparative cognition

Among the many important empirical and theoretical contributions in her career Clayton and her colleagues advanced the idea that comparative cognition researchers would benefit from considering the role of magic and the techniques of the magician in some areas of cross-species cognitive study. They provided compelling and exciting studies using the techniques of the magician and demonstrated how those affect nonhuman animals that rely on vision, showing that there are similarities and dissimilarities in how susceptible some nonhuman species are to the magician's effects that typically work so well on human observers.

Beyond the Tricks: The Science and Comparative Cognition of Magic

Magic is an art form that has fascinated humans for centuries. Recently, the techniques used by magicians to make their audience experience the impossible have attracted the attention of psychologists, who, in just a couple of decades, have produced a large amount of research regarding how these effects operate, focusing on the blind spots in perception and roadblocks in cognition that magic techniques exploit. Most recently, this investigation has given a pathway to a new line of research that uses magic effects to explore the cognitive abilities of nonhuman animals. This new branch of the scientific study of magic has already yielded new evidence illustrating the power of magic effects as a psychological tool for nonhuman animals. This review aims to give a thorough overview of the research on both the human and nonhuman perception of magic effects by critically illustrating the most prominent works of both fields of inquiry.

Comparative cognition: Capuchin monkeys believe in magic

Capuchin monkeys are unique among New World monkeys for their manual dexterity and use of tools. New research using magical sleight of hand shows visual perception of others' actions paralleling their manual skills.

Manual action expectation and biomechanical ability in three species of New World monkey

Being able to anticipate another's actions is a crucial ability for social animals because it allows for coordinated reactions. However, little is known regarding how hand morphology and biomechanical ability influences such predictions. Sleight of hand magic capitalizes on the observer's expectations of specific manual movements,^1,2 making it an optimal model to investigate the intersection between the ability to manually produce an action and the ability to predict the actions of others. The French drop effect involves mimicking a hand-to-hand object transfer by pantomiming a partially occluded precision grip. Therefore, to be misled by it, the observer ought to infer the opposing movement of the magician's thumb.³ Here, we report how three species of platyrrhine with inherently distinct biomechanical ability^4,5,6-common marmosets (Callithrix jacchus), Humboldt's squirrel monkeys (Saimiri cassiquiarensis), and yellow-breasted capuchins (Sapajus xanthosternos)-experienced this effect. Additionally, we included an adapted version of the trick using a grip that all primates can perform (power grip), thus removing the opposing thumb as the causal agent of the effect. When observing the French drop, only the species with full or partial opposable thumbs were misled by it, just like humans. Conversely, the adapted version of the trick misled all three monkey species, regardless of their manual anatomy. The results provide evidence of a strong interaction between the physical ability to approximate a manual movement and the predictions primates make when observing the actions of others, highlighting the importance of physical factors in shaping the perception of actions.

Investigating expert performance when observing magic effects

The use of magic effects to investigate the blind spots in attention and perception and roadblocks in the cognition of the spectator has yielded thought-provoking results elucidating how these techniques operate. However, little is known about the interplay between experience practising magic and being deceived by magic effects. In this study, we performed two common sleight of hand effects and their real transfer counterparts to non-magicians, and to magicians with a diverse range of experience practising magic. Although, as a group, magicians identified the sleights of hand as deceptive actions significantly more than non-magicians; this ability was only evidenced in magicians with more than 5 years in the craft. However, unlike the rest of the participants, experienced magicians had difficulty correctly pinpointing the location of the coin in one of the real transfers presented. We hypothesise that this might be due to the inherent ambiguity of this transfer, in which, contrary to the other real transfer performed, no clear perceptive clue is given about the location of the coin. We suggest that extensive time practising magic might have primed experienced magicians to anticipate foul play when observing ambiguous movements, even when the actions observed are genuine.

The Ape That Lived to Tell the Tale. The Evolution of the Art of Storytelling and Its Relationship to Mental Time Travel and Theory of Mind

Engaging in the art of creating and telling stories is a defining behaviour of humankind. Humans have been sharing stories with each other, with and without words, since the dawn of recorded history, but the cognitive foundations of the behaviour can be traced deeper into our past. The emergence of stories can be strongly linked to Mental Time Travel (the ability to recall the past and imagine the future) and plays a key role in our ability to communicate past, present and future scenarios with other individuals, within and beyond our lifetimes. Stories are products engraved within the concept of time, constructed to elucidate the past experiences of the self, but designed with the future in mind, thus imparting lessons of such experiences to the receiver. By being privy to the experiences of others, humans can imagine themselves in a similar position to the protagonist of the story, thus mentally learning from an experience they might have never encountered other than in the mind's eye. Evolutionary Psychology investigates how the engagement in artistic endeavours by our ancestors in the Pleistocene granted them an advantage when confronted with obstacles that challenged their survival or reproductive fitness and questions whether art is an adaptation of the human mind or a spandrel of other cognitive adaptations. However, little attention has been placed on the cognitive abilities that might have been imperative for the development of art. Here, we examine the relationship between art, storytelling, Mental Time Travel and Theory of Mind (i.e., the ability to attribute mental states to others). We suggest that Mental Time Travel played a key role in the development of storytelling because through stories, humans can fundamentally transcend their present condition, by being able to imagine different times, separate realities, and place themselves and others anywhere within the time space continuum. We argue that the development of a Theory of Mind also sparked storytelling practises in humans as a method of diffusing the past experiences of the self to others whilst enabling the receiver to dissociate between the past experiences of others and their own, and to understand them as lessons for a possible future. We propose that when artistic products rely on storytelling in form and function, they ought to be considered separate from other forms of art whose appreciation capitalise on our aesthetic preferences.

Jays are sensitive to cognitive illusions

Jays hide food caches, steal them from conspecifics and use tactics to minimize cache theft. Jays are sensitive to the content of their own caches, retrieving items depending on their preferences and the perishability of the cached item. Whether jays impose the same content sensitivity when they steal caches is less clear. We adapted the 'cups-and-balls' magic routine, creating a cognitive illusion to test whether jays are sensitive to the (i) content of hidden items and (ii) type of displacement. Subjects were presented with two conditions in which hidden food was consistent with their expectations; and two conditions in which food was manipulated to violate their expectations by switching their second preferred food for their preferred food (up-value) or vice versa (de-value). Subjects readily accepted food when it was consistent with their expectations but were more likely to re-inspect the baited cup and alternative cup when their expectations were violated. In the de-value condition, jays exhibited longer latencies to consume the food and often rejected it. Dominant subjects were more likely to reject the food, suggesting that social factors influence their responses to cognitive illusions. Using cognitive illusions offers innovative avenues for investigating the psychological constraints in diverse animal minds.