Blinded by magic: eye-movements reveal the misdirection of attention

Errors in visual search: Are they stochastic or deterministic?

In any visual search task in the lab or in the world, observers will make errors. Those errors can be categorized as "deterministic": If you miss this target in this display once, you will definitely miss it again. Alternatively, errors can be "stochastic", occurring randomly with some probability from trial to trial. Researchers and practitioners have sought to reduce errors in visual search, but different types of errors might require different techniques for mitigation. To empirically categorize errors in a simple search task, our observers searched for the letter "T" among "L" distractors, with each display presented twice. When the letters were clearly visible (white letters on a gray background), the errors were almost completely stochastic (Exp 1). An error made on the first appearance of a display did not predict that an error would be made on the second appearance. When the visibility of the letters was manipulated (letters of different gray levels on a noisy background), the errors became a mix of stochastic and deterministic. Unsurprisingly, lower contrast targets produced more deterministic errors. (Exp 2). Using the stimuli of Exp 2, we tested whether errors could be reduced using cues that guided attention around the display but knew nothing about the content of that display (Exp3a, b). This had no effect, but cueing all item locations did succeed in reducing deterministic errors (Exp3c).

Differential Effects of Experience and Information Cues on Metacognitive Judgments About Others' Change Detection Abilities

This study explored the interaction between visual metacognitive judgments about others and cues related to the workings of System 1 and System 2. We examined how intrinsic cues (i.e., saliency of a visual change) and experience cues (i.e., detection/blindness) affect people's predictions about others' change detection abilities. In Experiment 1, 60 participants were instructed to notice a subtle and a salient visual change in a magic trick that exploits change blindness, after which they estimated the probability that others would detect the change. In Experiment 2, 80 participants watched either the subtle or the salient version of the trick and they were asked to provide predictions for the experienced change. In Experiment 1, participants predicted that others would detect the salient change more easily than the subtle change, which was consistent with the actual detection reported in Experiment 2. In Experiment 2, participants' personal experience (i.e., whether they detected the change) biased their predictions. Moreover, there was a significant difference between their predictions and offline predictions from Experiment 1. Interestingly, change blindness led to lower predictions. These findings point to joint contributions of experience and information cues on metacognitive judgments about other people's change detection abilities.

Magic, Bayes and wows: A Bayesian account of magic tricks

Magic tricks have enjoyed an increasing interest by scientists. However, most research in magic focused on isolated aspects of it and a conceptual understanding of magic, encompassing its distinct components and varieties, is missing. Here, we present an account of magic within the theory of Bayesian predictive coding. We present the "wow" effect of magic as an increase in surprise evoked by the prediction error between expected and observed data. We take into account prior knowledge of the observer, attention, and (mis-)direction of perception and beliefs by the magician to bias the observer's predictions and present a simple example for the modelling of the evoked surprise. The role of misdirection is described as everything that aims to maximize the surprise a trick evokes by the generation of novel beliefs, the exploitation of background knowledge and attentional control of the incoming information. Understanding magic within Bayesian predictive coding allows unifying all aspects of magic tricks within one framework, making it tractable, comparable and unifiable with other models in psychology and neuroscience.

Magic Curiosity Arousing Tricks (MagicCATs): A novel stimulus collection to induce epistemic emotions

There has been considerable interest in empirical research on epistemic emotions, i.e., emotions related to knowledge-generating qualities of cognitive tasks and activities such as curiosity, interest, and surprise. One big challenge when studying epistemic emotions is systematically inducting these emotions in restricted experimental settings. The current study created a novel stimulus set called Magic Curiosity Arousing Tricks (MagicCATs): a collection of 166 short magic trick video clips that aim to induce a variety of epistemic emotions. MagicCATs are freely available for research and can be used in a variety of ways to examine epistemic emotions. Rating data also support that the magic tricks elicit a variety of epistemic emotions with sufficient inter-stimulus variability, demonstrating good psychometric properties for their use in psychological experiments.

On the cognitive bases of illusionism

Cognitive scientists have paid very little attention to magic as a distinctly human activity capable of creating situations that are considered impossible because they violate expectations and conclude with the apparent transgression of well-established cognitive and natural laws. This illusory experience of the "impossible" entails a very particular cognitive dissonance that is followed by a subjective and complex "magical experience". Here, from a perspective inspired by visual neuroscience and ecological cognition, we propose a set of seven fundamental cognitive phenomena (from attention and perception to memory and decision-making) plus a previous pre-sensory stage that magicians interfere with during the presentation of their effects. By doing so, and using as an example the deconstruction of a classic trick, we show how magic offers novel and powerful insights to study human cognition. Furthermore, live magic performances afford to do so in tasks that are more ecological and context-dependent than those usually exploited in artificial laboratory settings. We thus believe that some of the mysteries of how the brain works may be trapped in the split realities present in every magic effect.

Microsaccades reflect the dynamics of misdirected attention in magic

The methods of magicians provide powerful tools for enhancing the ecological validity of laboratory studies of attention. The current research borrows a technique from magic to explore the relationship between microsaccades and covert attention under near-natural viewing conditions. We monitored participants' eye movements as they viewed a magic trick where a coin placed beneath a napkin vanishes and reappears beneath another napkin. Many participants fail to see the coin move from one location to the other the first time around, thanks to the magician's misdirection. However, previous research was unable to distinguish whether or not participants were fooled based on their eye movements. Here, we set out to determine if microsaccades may provide a window into the efficacy of the magician's misdirection. In a multi-trial setting, participants monitored the location of the coin (which changed positions in half of the trials), while engaging in a delayed match-to-sample task at a different spatial location. Microsaccades onset times varied with task difficulty, and microsaccade directions indexed the locus of covert attention. Our combined results indicate that microsaccades may be a useful metric of covert attentional processes in applied and ecologically valid settings.

Cross-modal attentional entrainment: Insights from magicians

Recently, performance magic has become a source of insight into the processes underlying awareness. Magicians have highlighted a set of variables that can create moments of visual attentional suppression, which they call "off-beats." One of these variables is akin to the phenomenon psychologists know as attentional entrainment. The current experiments, inspired by performance magic, explore the extent to which entrainment can occur across sensory modalities. Across two experiments using a difficult dot probe detection task, we find that the mere presence of an auditory rhythm can bias when visual attention is deployed, speeding responses to stimuli appearing in phase with the rhythm. However, the extent of this cross-modal influence is moderated by factors such as the speed of the entrainers and whether their frequency is increasing or decreasing. In Experiment 1, entrainment occurred for rhythms presented at .67 Hz, but not at 1.5 Hz. In Experiment 2, entrainment only occurred for rhythms that were slowing from 1.5 Hz to .67 Hz, not speeding. The results of these experiments challenge current models of temporal attention.

The ball vanishes in the air: can we blame representational momentum?

In the vanishing ball illusion (VBI), the magician throws a ball up into the air twice and then pretends to do a third throw. On the third (fake) throw, the audience sees the ball go up and then disappear. In this article, we study the psychological mechanisms at play in this magic trick. We test the hypothesis that the illusion is based on representational momentum (RM), a psychological phenomenon in which the observer perceives the stopping point of a moving scene as being located farther ahead in the direction of motion than it really is. To determine whether the mechanisms involved in VBI are similar to those underlying RM, we compared the results of a standard VBI task to those obtained on an RM task designed to be very close to the VBI task. The results showed that VBI sensitivity was not associated with a higher anticipation score on the RM task. Unexpectedly, we found that participants who were sensitive to the illusion even obtained a weaker RM effect. We discuss several hypotheses that might account for these results.

Don't get misdirected! Differences in overt and covert attentional inhibition between children and adults

Previous research has revealed marked improvements in cognitive control between the age of 10 years and adulthood. The aim of the current study was to explore differences in attentional control between adults and children within a natural context, namely whilst they were watching a magic trick. We measured participants' eye movements whilst they watched a misdirection trick in which attentional misdirection was used to prevent observers from noticing a salient visual event. Half of our participants failed to detect this event even though it took place in full view. Children below the age of 10 were significantly less likely to notice the event than the adults and were also more reliably overtly misdirected (i.e., where they looked). Our results illustrate that within a more naturalistic context children are significantly more distracted than adults, and this distraction can have major implications on their visual awareness.

Can Magic Deception Be Detected at an Unconscious Level?

Magicians present magic tricks that seem to defy the laws of nature, entertaining us by manipulating our attention, perception, and awareness. However, although we are unaware of these manipulations at the level of conscious experience, we may still be aware of them at an unconscious level. We examined whether people can detect a magic deception outside of conscious awareness using an indirect measure. In the present study, we used the Cups and Balls magic trick, which is the transposition of balls between two cups. Participants viewed a video of the magic performance and were required to indicate the position of the ball in a direct self-report measure and completed the Single Category Implicit Association Test as an indirect measure. The results showed that the indirect measure of trick detection had higher accuracy than the direct measure. Our results suggest that while humans cannot consciously detect the magic deception, they do have a sense of what occurred on an unconscious level.

The Phantom Vanish Magic Trick: Investigating the Disappearance of a Non-existent Object in a Dynamic Scene

Drawing inspiration from sleight-of-hand magic tricks, we developed an experimental paradigm to investigate whether magicians’ misdirection techniques could be used to induce the misperception of “phantom” objects. While previous experiments investigating sleight-of-hand magic tricks have focused on creating false assumptions about the movement of an object in a scene, our experiment investigated creating false assumptions about the presence of an object in a scene. Participants watched a sequence of silent videos depicting a magician performing with a single object. Following each video, participants were asked to write a description of the events in the video. In the final video, participants watched the Phantom Vanish Magic Trick, a novel magic trick developed for this experiment, in which the magician pantomimed the actions of presenting an object and then making it magically disappear. No object was presented during the final video. The silent videos precluded the use of false verbal suggestions, and participants were not asked leading questions about the objects. Nevertheless, 32% of participants reported having visual impressions of non-existent objects. These findings support an inferential model of perception, wherein top-down expectations can be manipulated by the magician to generate vivid illusory experiences, even in the absence of corresponding bottom-up information.

Magic and Misdirection: The Influence of Social Cues on the Allocation of Visual Attention While Watching a Cups-and-Balls Routine

In recent years, a body of research that regards the scientific study of magic performances as a promising method of investigating psychological phenomena in an ecologically valid setting has emerged. Seemingly contradictory findings concerning the ability of social cues to strengthen a magic trick’s effectiveness have been published. In this experiment, an effort was made to disentangle the unique influence of different social and physical triggers of attentional misdirection on observers’ overt and covert attention. The ability of 120 participants to detect the mechanism of a cups-and-balls trick was assessed, and their visual fixations were recorded using an eye-tracker while they were watching the routine. All the investigated techniques of misdirection, including sole usage of social cues, were shown to increase the probability of missing the trick mechanism. Depending on the technique of misdirection used, very different gaze patterns were observed. A combination of social and physical techniques of misdirection influenced participants’ overt attention most effectively.