Social misdirection fails to enhance a magic illusion

Abstract

Visual, multisensory and cognitive illusions in magic performances provide new windows into the psychological and neural principles of perception, attention, and cognition. We investigated a magic effect consisting of a coin "vanish" (i.e., the perceptual disappearance of a coin after a simulated toss from hand to hand). Previous research has shown that magicians can use joint attention cues such as their own gaze direction to strengthen the observers' perception of magic. Here we presented naïve observers with videos including real and simulated coin tosses to determine if joint attention might enhance the illusory perception of simulated coin tosses. The observers' eye positions were measured, and their perceptual responses simultaneously recorded via button press. To control for the magician's use of joint attention cues, we occluded his head in half of the trials. We found that subjects did not direct their gaze at the magician's face at the time of the coin toss, whether the face was visible or occluded, and that the presence of the magician's face did not enhance the illusion. Thus, our results show that joint attention is not necessary for the perception of this effect. We conclude that social misdirection is redundant and possibly detracting to this very robust sleight-of-hand illusion. We further determined that subjects required multiple trials to effectively distinguish real from simulated tosses; thus the illusion was resilient to repeated viewing.

Keywords: eye movements; fixation; free-viewing; join attention; motion perception; prestidigitation; sleight-of-hand; social misdirection.

Figure 1

Design and results from Experiment 1: “Magic Trick versus Real Toss, without Reveal.” (A) Sequence of static images selected from the Magic Trick (Upper Row) and Real Toss (Lower Row) video clips. The red circles indicate the veridical location of the coin, at any given time. (B) Percentage of coin toss reports, per 10-trial block, per experimental condition. Error bars represent SEM across subjects (N = 9). (C) Percentage of coin toss reports, trial by trial, per experimental condition (N = 9 subjects).

Figure 2

Design and results from Experiment 2: “Magic Trick versus Real Toss, with Reveal.” (A) Sequence of static images selected from the Magic Trick with Reveal (Upper Row) and Real Toss with Reveal (Lower Row) video clips. The “Reveal” image selected for both video clips corresponds to the last frame of the performance. The red circles indicate the veridical location of the coin, at any given time. (B) Percentage of coin toss reports, per trial block, per experimental condition. Error bars represent SEM across subjects (N = 8). (C) Percentage of coin toss reports, trial by trial, per experimental condition (N = 8 subjects).

Figure 3

Signal detection analysis of the effect of the “Reveal” stage. Left Column: Detection sensitivity and response bias of Experiment 1 (No Reveal) versus Experiment 2 (Reveal). Middle Column: Detection sensitivity and response bias for the first 10 trials only. Right Column: Detection sensitivity and response bias for the last 40 trials. Error bars indicate SEM across subjects. *Paired t-test, p < 0.05.

Figure 4

Design of Experiment 3: “Multiple Toss Conditions, with Reveal.” (A) Sequence of static images selected from the various coin toss conditions presented: Magic Trick, Real Toss, Two-Coin Fake Toss, Final Coin Fake Toss, and No Coin Fake Toss. (B) Upper and Lower Rows: Free-exploration (Upper Row) and fixation (Lower Row) viewing conditions. Green dotted boxes (Lower Row) indicate the 2° × 2° fixation window; fixation cross not to scale. Left and Right Columns: Magician’s face visible (Left Column) and occluded (Right Column).

Figure 5

Average percentage of coin toss reports according to type of performance. (A) Free-viewing condition. (B) Fixation condition. Error bars represent SEM across subjects (N = 8). *Paired t-test, p < 0.05.

Figure 6

Average percentage of coin toss reports according to viewing condition, presence of an initial coin, and presence/absence of social misdirection. (A) Percentages of button presses for free-viewing and fixation conditions, with the magician’s face visible versus occluded. Error bars represent SEM across all five types of performance (N = 5 conditions). (B) Percentages of button presses for types of performance in which an initial coin was present versus absent, with the magician’s face visible versus occluded. Error bars under Initial Coin condition represent SEM across six conditions, i.e., Face visible and Face occluded, for Magic Trick, Real Toss and Two-Coin Fake Toss. Error bars under No Initial Coin condition represent SEM across four conditions, i.e., Face visible and Face occluded, for Final Coin Fake Toss and No Coin Fake Toss. (C) Percentages of button presses according to the presence/absence of an initial coin, with free-viewing versus fixation conditions. Error bars under Initial Coin condition represent SEM across six conditions, i.e., Free-viewing and Fixation, for Magic Trick, Real Toss and Two-Coin Fake Toss. Error bars under No Initial Coin condition represent SEM across four conditions, i.e., Free-viewing and Fixation, for Final Coin Fake Toss and No Coin Fake Toss. *Paired t-test, p < 0.05; **Paired t-test, p < 0.001; +Two-sample t-test, p < 0.05; ++Two-sample t-test, p < 0.001.

Figure 7

Signal detection analyses of the effect of face visibility, presence of an initial coin and viewing task. Left Column: Detection sensitivity and response bias of Face Visible versus Face Occluded conditions. Right Column: Detection sensitivity and response bias of Free-viewing versus Fixation conditions. Error bars indicate SEM across subjects. *Paired t-test, p < 0.05.

Figure 8

Distribution of gaze location for free-viewing trials. (A) Magic Trick; (B) Real Toss; (C) Two Coins Fake Toss; (D) Final Coin Fake Toss; (E) No Coin Fake Toss. The upper section of each panel illustrates the time distribution of the subjects’ gaze location. The red horizontal segments indicate when the subjects looked at the magician’s face area, trial-by-trial. The three white vertical lines indicate the beginning of the coin toss, the end of the toss, and the beginning of the reveal. The green dots indicate the time of button press. Trials are sorted according to the subjects’ reaction time, from fastest to slowest. The brown and orange lines illustrate the probability with which the subjects’ gaze fell on the magician’s face area; the brown and orange triangles indicate the mean time of button presses. The small circles on the lines indicating probability of gaze in the face area represent the selected time locations for error bar calculation. Error bars indicate one SD. The lower section of each panel represents the spatial distribution of the subjects’ gaze for each experimental condition. The hotter the color, the higher the probability that the subjects’ gaze was located in that area.

Figure 9

Probability of the subjects’ gaze on the magician’s face area 500 ms before versus 500 ms after the button press. Error bars indicate one SD.