Scientists Hypnotized People To Have Synesthesia-Like Experiences


Rachel Baxter

Copy Editor & Staff Writer


Have you ever been able to taste words or smell sounds? Do you always see words in their own specific color? Well, if the answer’s yes, you might have synaesthesia. If you have no idea what I’m talking about, you probably don’t have synaesthesia, but you could perhaps be hypnotized to experience something vaguely like it, according to new research.

Synaesthesia is a unique condition in which the stimulation of one sensory or cognitive pathway, like the ones for vision or smell, leads to an involuntary experience in another pathway. So, reading a word might activate the pathway that leads to taste, giving some people the ability to taste words.


It has certainly baffled scientists for some time, but they have managed to come to a few conclusions. Synesthesia seems to have a hereditary element to it, and it appears that being a woman and left-handed increases your chance of having it. Estimates suggest that anywhere between one in every 200 and one in every 20,000 people have the condition. It’s also thought to be due to some kind of “cross-wiring” in the brain that happens during development.

But what if non-synesthetes could be made to experience the unique “superpowers” that synesthetic people have every day? Now, scientists from the University of Skövde in Sweden and Finland’s University of Turku have tried to do just that, by using the power of hypnosis. Their findings, which are based only on eight subjects (half of whom acted as controls), are published in the journal Scientific Reports.

First things first, only about 10 percent of people are highly susceptible to hypnosis. So the researchers had to carefully select their participants. They put 61 volunteers through a hypnotic susceptibility test and found eight potentials. These people were then subjected to the Stroop task, which involves naming the colors of shapes in a grid. From this, four of the volunteers were found to be hypnotically suggestible, while the other four acted as controls.

The participants were then triggered into hypnosis by the phrase “soon I will count to three…” that had been implanted earlier on. They were then hypnotized to see all shapes as one color, even if this differed from its real color. The researchers recorded their responses, as well as tracked their eye movements with special software.


The results showed that of the four people susceptible to hypnosis, three appeared to have gained a strong association between symbol and color, suggesting that they had developed a synaesthesia-like sensation.

“However, the nature of this association varied widely,” noted Sakari Kallio from the University of Turku. “Two participants reported that they visually experienced the symbols as having the suggested color: in one case with full self-awareness of doing so and in another case not."

The third person wasn’t aware of the suggestions and didn’t experience any color change, but still had difficulties naming the real colors of the symbols. Meanwhile, the controls failed to reproduce the synesthetic experience.  

Interesting as these results are, the team highlights that further studies are needed to determine whether synaesthesia really can be brought on by hypnosis. After all, a sample size of four is far too tiny to go on. It’s also difficult to link the experiences from hypnotic suggestion to synaesthesia itself.


Nevertheless, the findings in combination with other studies may help in terms of finding out more about perception and sensation. "Perhaps most importantly, the results showed both definite similarities and clear differences to naturally occurring synaesthesia,” said Kallio.


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  • Synesthesia,

  • hypnosis