How do magicians play with our minds?

The inattentive blindness, or in other words, '' the failure to detect an unexpected stimulus that is in our field of vision when carrying out other tasks that occupy our attention ’’ is one of the strategies that magicians and illusionists have practiced for decades to deceive our brain. This phenomenon, called in English Inattentional blindness it is classified as a ‘’ attention error ’’ and has nothing to do with any visual deficit. In fact, it is a strategy of our mind to try to tackle the stimulating overload to which we constantly expose ourselves.

However, this ruse is not the only one used by magicians to mislead us.

Among the studies carried out in the field of neuroscience there is a very interesting article in which two researchers, Stephen L. Macknik and Susana Martínez Conde proposed find the mechanisms that are produced so that our brain is unable to perceive the tricks that magicians use in their performances. To do this, they had the collaboration of authentic professional magicians such as Penn and Teller (see article here).

Tricks and tricks most used by magicians

These authors state that among the various tricks that illusionists use to deceive us are:

1) Optical illusions and other sensory illusions, which are phenomena in which the subjective perception of a fact does not agree with the physical reality of it.

A very plastic example that illustrates this is the trick of the bending spoons. In this number, the magician bends the spoon so that its handle appears flexible.

The fact that we perceive this visual illusion is due to the sensitive neurons of the visual cortex, both to the movement as to the endings of the lines, they respond differently to oscillations than other neurons visuals. The result is an apparent discrepancy between the endings of a stimulus and its center; a solid object appears to flex in the middle. This ‘’ neuronal desynchronization ’’ is what makes the spoon seem to be bending.

Another variant of this trick consists of using two spoons that are bent beforehand in a moment of distraction from the spectators. The magician holds them between the thumb and forefinger so that they meet at the bent part of both. It appears to be holding two unbent, crossed spoons at the neck of the handle. When you start to shake them, the spoons seem to soften and bend at the neck. This optical phenomenon, also known as law of good continuity, makes us see the spoons as if they crossed when the magician holds them, despite the fact that they are already bent.

2) Cognitive illusions such as change blindness in which the viewer is not able to perceive that there is something different from what there was before. Change may or may not be expected, and it may be sudden or gradual regardless of interruptions.

Among the cognitive illusions is also the inattentive or inattentive blindness, which we have already mentioned above.

Below are some videos that illustrate this fact:

Is the eye or the brain fooled?

A question that arises about how magicians manage to sneak their tricks is if it is due to distracting our gaze of the moment in which they perform the trick or in reality, what they manipulate is ours attention. Kuhn and Tatler (2005) carried out an experiment consisting of controlling the movements of the spectators' eyes before a simple trick that consisted of making a cigarette (the magician threw it under the table) and what they saw was that the spectator was looking at the cigarette at all times but still they did not see the trick. The conclusions of the study were that what the magician was actually doing was manipulating the attention of the viewer rather than his gaze, using the same principles used to produce blindness inattentive.

How does our brain approach 'the impossible'?

In a 2006 study by Kuhn and others cognitive neuroscientists, the experimental subjects were asked to watch videos of magic tricks that appeared to exhibit impossible causal relationships, such as making a ball disappear. At the same time, functional magnetic resonance images of his brain were taken. A control group watched very similar videos, though not including magic tricks.

The results indicated increased activation in the anterior cingulate cortex between the subjects who were observing magic tricks than between the controls.

The discovery suggests that this brain area may be important for interpreting causal relationships.

This work by Kuhn and his colleagues only hints at the extent to which magic techniques could manipulate the attention of individuals and their ability to become aware of what is happening, to, meanwhile, investigate the physiology of their brains.

Bibliographic references:

• Kuhn, G. & Tatler, B. W. (2005). Magic and fixation: now you don't see it, now you do. Perception 34, 1155–1161

• Macknik, S.L., Martínez-Conde, S. (2013). Tricks of the Mind: How Magic Tricks Reveal the Functioning of the Brain. Barcelona: Destination.

• Stephen L. Macknik, Mac King, James Randi, Apollo Robbins, Teller, John Thompson, and Susana Martinez-Conde. (2008). Attention and awareness in stage magic: turning tricks into research. Nature Reviews Neuroscience. doi: 10.1038 / nrn2473