Synesthesia, people with the ability to see sounds and taste colors.

The ability to perceive sensations in an unusual way.

It is quite obvious that, for most people, receiving light on the retina means having a visual sensation, just as having something come into contact with our skin generates a tactile sensation or receiving sound waves in our ears causes us to hear something. However, this scheme of events is not always so simple.

There are some people who experience a phenomenon called synesthesiawhich consists of perceiving sensations originating in several sensory channels..

Where synesthesia occurs, one type of stimulation evokes the sensation of another. Thus, some people with synaesthesia can see sounds, while others can taste tactile sensations, etc. For example, one of the best-known cases is that of the physicist Richard Feynman, who claimed to see colored equations in claimed to see equations in colorsBut the range of combinations of sensations that can be produced as a form of synaesthesia is really very wide: sounds that generate flavors, numbers and letters that are perceived as colors, etc.

Why does synaesthesia occur?

A large part of the community of neuroscientists in charge of studying synaesthesia believe that it is produced by a kind of "crossing of wires". Thus, they propose the explanation that at the moment when this phenomenon occurs, vSeveral neuron channels associated with different senses interfere with each other, so that the information from the mediumThe information from the surrounding environment that arrives through a sensory organ reaches the brain and is transformed into another type of sensation.

Hence, people who experience this see their senses mix involuntarily and without being able to consciously regulate this transfer of information from one sensory type to the other, and hence there may also be cases in which blind synaesthetes can still experience colors by touching, hearing, etc.

Synaesthetic people may have a somewhat unique brain.

Ultimately, the brains of people who experience synaesthesia seems to have a somewhat different architecture than that of the rest of the populationHowever, this does not mean that their nervous system is damaged or that they are less able to live a normal and autonomous life. In fact, because of the automatic and partially unconscious nature of synaesthesia, it is not unusual for a person to have been mixing sensations all his life and not realize how peculiar what is happening to him is, or believe that it happens to everyone else.

How widespread is synaesthesia?

Synaesthesia, under its different forms and types, is not something that occurs rarely in those people who experience it, and therefore it is possible that it is well assimilated and considered the normal way of perceiving reality, since it is part of the daily life of many people.

The fact that many people are synaesthetes without being aware of it makes it difficult to estimate the percentage of the population that is synaesthetes, but recently there have been indications that synaesthesia is surprisingly widespread. It may be part of the daily lives of 4 or 5 out of every 100 people, considerably more than was believed at the end of the 20th century, with the most frequent type being that of associating days with colors. In addition, curiously, it is more widespread in people with autism, which in the future may provide clues to understand the origin and causes of this type of disorders.

Are we all synaesthetes?

Something to keep in mind is that there are phenomena very similar to synaesthesia that are very generalized, which could mean that almost all of us are synaesthetes to a greater or lesser extent.. 

For example, it is very normal for us to associate sharp, angular shapes with sounds such as the letter "k", while rounded contours are easier to relate to the sound of "b", although this does not respond to any kind of logical reasoning. This type of thinking has also been referred to by psychologists as cognitive biases.. You can learn more about this by reading this article:

• "Cognitive biases: discovering an interesting psychological effect".

The same happens with many other elements of our day-to-day life: we talk about acid humor, sharp tonguesetc. In case we hypothesize that these phenomena are mild cases of synesthesia, our way of understanding el funcionamiento normal de las vías sensoriales se revelaría como algo más complejo de lo que pensábamos.

Referencias bibliográficas:

• Baron-Cohen, S., Johnson, D., Asher, J., Wheelwright, S., Fisher, S. E., Gregersen, P. K., Allison, C. (2013). Is synaesthesia more common in autism? Molecular Autism, 4(1), p. 40.
• Simner, J., Mulvenna, C., Sagiv, N., Tsakanikos, E., Witherby, S. A., Fraser, C. Scott, K. Ward, J. (2006). Synaesthesia: The prevalence of atypical cross-modal experiences. Perception, 35(8), pp. 1024 - 1033.
• Steven, M. S. y Blakemore, C. (2004). Visual synaesthesia in the blind.Perception, 33(7), pp. 855 - 868.