“Never Repeat the Same Trick Twice—Unless It Is Cognitively Impenetrable”, Vebjørn Ekroll, Evy De Bruyckere, Lotte Vanwezemael, Johan Wagemans2018 (, ; backlinks)⁠:

[cf. Svalebjørg et al 2020 on subjective experience even after solution] In their quest for creating magical experiences, magicians rely on a host of psychological factors. Here, we compare tricks based on attentional misdirection with tricks based on amodal completion. Based on the notion that amodal completion is a cognitively impenetrable perceptual phenomenon, we predicted that the tricks based on this perceptual effect should—to a much larger extent than tricks based on attentional misdirection—retain their deceptive power when the tricks are repeated.

The results of an experiment with 4 magic tricks involving attentional misdirection and 4 magic tricks based on amodal completion lend strong support to this prediction. Asking subjects to try to figure out the secret behind these tricks after one, two, or 3 presentations of each trick, we found that the observed solution rates for tricks based on attentional misdirection increased much more with repeated viewing than those for tricks based on amodal completion, which remained very low throughout.

Thus, the results lend further support to the idea that amodal completion is based on cognitively impenetrable perceptual mechanisms.

Figure 2: Percentage of the subjects who found out the secret behind the magic tricks plotted against the number of times the trick had been viewed. Note that the solution rates are always lower for the tricks based on amodal completion (dotted lines) and tend to increase less with the number of presentations.

…A clear result of our experiment is that solution rates for the tricks based on amodal completion are very low after the first presentation and increase only marginally with repeated presentations (Figure 2). Even after the third presentation, the highest solution rate for any of the tricks based on amodal completion was only 19%, while the lowest solution rate for any of the other tricks was more than twice of that (42%). Compared with all of the other tricks, all of the tricks based on amodal completion have lower solution rates at all presentation times. In principle, one may argue that the larger increases in solution rates with repeated presentation for the tricks based on attentional misdirection may, at least in part, be a consequence of the higher initial solution rates for these tricks. However, as we have shown, some of the tricks based on attentional misdirection have initial solution rates which are almost as low as those of the tricks based on amodal completion, but the solution rates nevertheless increase much more quickly with repetition. Thus, we can be fairly confident that tricks based on amodal completion are much less susceptible to the detrimental effects of repetition than the tricks based on attentional misdirection.

…our experiment does not provide strong evidence that tricks based on attentional misdirection are generally inferior to tricks based on amodal completion with respect to their deceptive power at the first presentation. As we have already argued earlier, though, our results strongly suggest that tricks based on amodal completion are considerably more robust at repeated presentations.

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