Choosing in freedom or forced to choose? Introspective blindness to psychological forcing in stage-magic

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.

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

In recent years, scientists have begun to use magic effects to investigate the blind spots in our attention and perception [G. Kuhn, Experiencing the Impossible: The Science of Magic (2019); S. Macknik, S. Martinez-Conde, S. Blakeslee, Sleights of Mind: What the Neuroscience of Magic Reveals about Our Everyday Deceptions (2010)]. Recently, we suggested that similar techniques could be transferred to nonhuman animal observers and that such an endeavor would provide insight into the inherent commonalities and discrepancies in attention and perception in human and nonhuman animals [E. Garcia-Pelegrin, A. K. Schnell, C. Wilkins, N. S. Clayton, Science 369, 1424-1426 (2020)]. Here, we performed three different magic effects (palming, French drop, and fast pass) to a sample of six Eurasian jays (Garrulus glandarius). These magic effects were specifically chosen as they utilize different cues and expectations that mislead the spectator into thinking one object has or has not been transferred from one hand to the other. Results from palming and French drop experiments suggest that Eurasian jays have different expectations from humans when observing some of these effects. Specifically, Eurasian jays were not deceived by effects that required them to expect an object to move between hands when observing human hand manipulations. However, similar to humans, Eurasian jays were misled by magic effects that utilize fast movements as a deceptive action. This study investigates how another taxon perceives the magician's techniques of deception that commonly deceive humans.

Subtly encouraging more deliberate decisions: using a forcing technique and population stereotype to investigate free will

Magicians' forcing techniques allow them to covertly influence spectators' choices. We used a type of force (Position Force) to investigate whether explicitly informing people that they are making a decision results in more deliberate decisions. The magician placed four face-down cards on the table in a horizontal row, after which the spectator was asked to select a card by pushing it forward. According to magicians and position effects literature, people should be more likely to choose a card in the third position from their left, because it can be easily reached. We manipulated whether participants were reminded that they were making a decision (explicit choice) or not (implicit choice) when asked to select one of the cards. Two experiments confirmed the efficiency of the Position Force-52% of participants chose the target card. Explicitly informing participants of the decision impairs the success of the force, leading to a more deliberate choice. A range of awareness measures illustrates that participants were unaware of their stereotypical behaviours. Participants who chose the target card significantly underestimated the number of people who would have chosen the same card, and felt as free as the participants who chose another card. Finally, we tested an embodied-cognition idea, but our data suggest that different ways of holding an object do not affect the level of self-control they have over their actions. Results are discussed in terms of theoretical implications regarding free will, Wegner's apparent mental causation, choice blindness and reachability effects.

Mind Control Tricks: Magicians' Forcing and Free Will

A new research program has recently emerged that investigates magicians' mind control tricks, also called forces. This research highlights the psychological processes that underpin decision-making, illustrates the ease by which our decisions can be covertly influenced, and helps answer questions about our sense of free will and agency over choices.

The apparent action causation: Using a magician forcing technique to investigate our illusory sense of agency over the outcome of our choices

We often fall victim of an illusory sense of control and agency over our thoughts and actions. Magicians are masters at exploiting these illusions, and forcing techniques provide a powerful way to study apparent action causation-the illusion that our action caused the outcome we get. In this article, we used the Criss-Cross force to study whether people can tell the difference between an action which had an impact on the outcome they get and one which has no impact. In the Criss-Cross force, participants are asked to cut to a card, and while they are genuinely free to cut the cards at any position, the cut does not affect the card they are given (i.e., they always get the top card). We investigate the psychological processes that underpin the success of this force. Experiment 1 (N = 60) showed that participants cannot tell the difference between a forced and a controlled outcome. Experiment 2 (N = 90) showed that contrary to common magicians' knowledge, misdirection does not play a role in the success of the force. Finally, Experiment 3 (N = 60) suggests that rather than misdirection, an attribute substitution error explains why people fail to understand that their action does not have an impact on the outcome they get. Debriefing also shows the importance of participants' expectations in the perception of the trick, as well as the role of prediction of the outcome in participants' sense of agency over the events.

Long-term memory of real-world episodes is independent of recency effects: magic tricks as ecological tasks

How episodic memories decay is an unresolved question in cognitive neuroscience. The role of short-term mechanisms regarding the decay of episodic memories is circumscribed to set the maximum recall from which a monotonic decay occurs. However, this sequential view from the short to the long-term is not compulsory, as short-term dependent memory gains (like recency effects when memorizing a list of elements; serial-position effects) may not be translated into long-term memory differences. Moreover, producing memorable events in the laboratory faces important challenges, such as recreating realistic conditions with elevated recall, or avoiding spontaneous retrievals during memory retention (sociocultural hooks). The current study proposes the use of magic to enhance the study of memory. We designed a sequence of magic tricks performed live on stage to evaluate the interaction between memory decay and serial-position effects of those tricks. The audience was asked to freely recall the tricks at four different timepoints: just after the show, 10 days, 1.5 months and 4.5 months. We discovered serial-position differences after the show that were no longer present later on, suggesting that short-term memory gains do not translate into the long-term. Illustrating the power of naturalistic stimuli to study long-term memory while interrogating the interaction between short-term and long-term mechanisms, this work is, to our knowledge, the first scientific study of the memorability of magic tricks.

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.

Influencing choices with conversational primes: How a magic trick unconsciously influences card choices

Past research demonstrates that unconscious primes can affect people's decisions. However, these free choice priming paradigms present participants with very few alternatives. Magicians' forcing techniques provide a powerful tool to investigate how natural implicit primes can unconsciously influence decisions with multiple alternatives. We used video and live performances of the mental priming force. This technique uses subtle nonverbal and verbal conversational primes to influence spectators to choose the three of diamonds. Our results show that a large number of participants chose the target card while reporting feeling free and in control of their choice. Even when they were influenced by the primes, participants typically failed to give the reason for their choice. These results show that naturally embedding primes within a person's speech and gestures effectively influenced people's decision making. This raises the possibility that this form of mind control could be used to effectively manipulate other mental processes.

A massive experiment on choice blindness in political decisions: Confidence, confabulation, and unconscious detection of self-deception

We implemented a Choice Blindness Paradigm containing political statements in Argentina to reveal the existence of categorical ranges of introspective reports, identified by confidence and agreement levels, separating easy from very hard to manipulate decisions. CBP was implemented in both live and web-based forms. Importantly, and contrary to what was observed in Sweden, we did not observe changes in voting intentions. Also, confidence levels in the manipulated replies where significantly lower than in non-manipulated cases even in undetected manipulations. We name this phenomenon unconscious detection of self-deception. Results also show that females are more difficult to manipulate than men.

Pupil size tracks perceptual content and surprise

Changes in pupil size at constant light levels reflect the activity of neuromodulatory brainstem centers that control global brain state. These endogenously driven pupil dynamics can be synchronized with cognitive acts. For example, the pupil dilates during the spontaneous switches of perception of a constant sensory input in bistable perceptual illusions. It is unknown whether this pupil dilation only indicates the occurrence of perceptual switches, or also their content. Here, we measured pupil diameter in human subjects reporting the subjective disappearance and re-appearance of a physically constant visual target surrounded by a moving pattern ('motion-induced blindness' illusion). We show that the pupil dilates during the perceptual switches in the illusion and a stimulus-evoked 'replay' of that illusion. Critically, the switch-related pupil dilation encodes perceptual content, with larger amplitude for disappearance than re-appearance. This difference in pupil response amplitude enables prediction of the type of report (disappearance vs. re-appearance) on individual switches (receiver-operating characteristic: 61%). The amplitude difference is independent of the relative durations of target-visible and target-invisible intervals and subjects' overt behavioral report of the perceptual switches. Further, we show that pupil dilation during the replay also scales with the level of surprise about the timing of switches, but there is no evidence for an interaction between the effects of surprise and perceptual content on the pupil response. Taken together, our results suggest that pupil-linked brain systems track both the content of, and surprise about, perceptual events.

A framework for using magic to study the mind

Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind—knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind? We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various approaches—both old and new—are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks—methods and effects together—as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder.