With the right stimuli, and in a few seconds, we can come to believe that a plastic arm belongs to us. A group of scientists has just shown that the same effect can be caused with a lying tongue.
Our brain's ability to adapt to circumstances begins to exceed our most optimistic expectations. Neuroscientists have known for years that the somatosensory system is capable of adapting to new developments with astonishing ease. The best-known experiment is carried out with a rubber arm and consists of simultaneously stimulating a person with his real arm (which is out of sight) and the hairpiece. After a few seconds, due to the coordination of stimuli and the powerful influence of our visual perception, our brain assumes that the arm in front of us, despite its artificial appearance, is ours. And we even have the reflex to withdraw our hand if someone brings a knife to it.
When they thought the limit of versatility had been reached, other scientists tried the same experiment but without covering the real arm. And it kept working. We quickly assume that we have a third arm and in virtual reality tests, with a bit of deception, we can feel that our arm is stretched several meters or that our body increases in size or shrinks to impossible sizes. There is nothing that is put ahead if our eyes tell us that this is our body.
A rubber tongue like the one used in the experiment (Magicdiscount)
With all these precedents, the team led by Charles Michel, from the 'Crusade' Research Laboratory, Oxford University, wanted to test other parts of the body and designed a series of experiments with a rubber tongue. The work, published this week in Perception magazine, consisted of recruiting 32 volunteers and trying to trick their brain with a simple device. The subjects stuck out their tongues and looked through a box where, through mirrors, they saw a plastic tongue in the place where theirs should be. The researchers then stimulated both languages at the same time, so that the person began to create the illusion that they were seeing their own language.
They ran a laser pointer across the surface of the rubber tongue, and the volunteers reported noticing.
The most interesting part of the research came when the scientists began running a green laser pointer across the surface of the rubber tongue and asked the volunteers what they felt. Twenty-two of the participants (68.75%) claimed to feel the laser on the tongue. Some felt cold, some hot, and some tingling. "I felt vibrations in my tongue synchronized with the movement of the light," says one. "The light was kind of rubbing the side of my tongue, " says participant 32. "When the light touched my tongue," says subject 24, "I noticed that the temperature was lower at that point."
"Can we feel flavors without having any kind of food in our mouth?"
The study shows once again that vision has such an influence on our brain that it modifies our perception to the point of feeling touch when it does not exist. "This is the first time that it has been proven that a tactile stimulus (on the tongue) can be perceived 'outside the body'", explains Charles to Next. "This is a perceptual illusion, in which we 'trick' the brain into believing that it is observing its own language, when in reality it was a rubber tongue!"
The experiment, from the perspective of the volunteer (Charles et al.)
This illusion occurs in large part because the taste is not only a sensation that obeys physical stimuli, but a reconstruction of our brain. The laboratory directed by Charles Spence has been researching in this regard for years, analyzing all the variables in the atmosphere or the environment that make a meal have one connotation or another. "In the future it will be possible to create unique taste sensations by integrating technologies of reversal reality (visual), physical and chemical stimuli", says Charles Michel.
In this sense, scientists believe that in addition to serving to better understand multisensory integration, this new effect can serve to experiment and create new culinary experiences. "A whole line of investigation opens up," says the researcher. "Will we ever be able to get the flavors out of our mouths? That is, can we feel flavors on our tongue, without having any type of food in our mouth? The answer promises to be interesting.