The Comparative Science of Magic: Using sleight of hand as a tool to investigate cognition in diverse taxa.
The use of magic effects in comparative cognition provides a powerful tool to investigate how diverse species perceive the world around them, by focusing on their shared psychological constraints rather than their cognitive prowess. In this thesis I explore how humans and non-human animals experience these techniques, and some of the nuances moderating this experience. After introducing the Science of Magic and proposing magic as a tool to investigate cognition in non-human animals in Chapter 1, Chapter 2 and Chapter 3 explore how multifaceted is the human experience of magic effects. In Chapter 2, I demonstrate how experience deceiving others using similar techniques moderate the expectations necessary to be misled by these effects, as expert magicians do not display the same biases when observing sleight of hand effects than typical observers. Chapter 3 shows how the order in which magic effects are presented within a routine moderate how the human audience will perceive the skill of the magician performing it. As a first step towards creating a Comparative Science of Magic, Chapter 4 reviews the similarities and differences in how both human and non-human audiences experience magic effects, evaluates the evolution of the craft by reviewing the deception tactics of non-human animals, and offers insight into the use of magic effects in the lab by reviewing potential candidates for such an endeavour. Chapter 5 takes inspiration from a well-known magic effect and uses it to investigate how Eurasian jays (Garrulus glandarius) experience illusions. Eurasian jays are sensitive to similar illusions that humans are, and this sensitivity is moderated by different nuances such as the type of effect (i.e., either negative or positive), or the social status of the avian observer. Chapter 6 and Chapter 7 provide comparisons of how diverse species with dissimilar anatomies and visual systems experience methodologically distinct sleight of hand effects. Both chapters provide evidence that anatomical ability and experience performing an action moderate how the pantomime movement of this action will be perceived. Alongside this, all species tested experienced the effect capitalising on fast motions similarly to each other regardless of their significant differences in their visual system, thus suggesting a convergently evolved blind spot or a product of common decent. Finally, Chapter 8 summarises the findings of this thesis and discusses the implications for the evolution of these nuances. Overall, the evidence presented in this thesis further reinforces the power and insight that using magic effects in psychology can apport in reference to the innerworkings and evolution of the human and the non-human mind.