The evolution of humans throughout the ages has applied selective pressure to key features and phenotypic characteristics that could, and still can, help human beings survive, communicate, eat, feel and… stand. A seminal paradigm of such hallmarks is the senses, which are all controlled by different parts of the brain. In fact, human senses are more than the basic five (touch, sight, hearing, smell and taste). For instance, proprioception is the sense of space, which allows the brain to “feel” where our body is located in space, based on feedback from the muscles. Furthermore, balance is a very complex sense that integrates information from many different systems of the body, including auditory and vestibular stimuli. So, what happens when one or more senses cross with each other?
Crossing of one or more senses together leads to synesthesia, a condition that causes the “joined perception” of two or more senses as one. Different types of synesthesia exist, where people have reported that they can taste shapes, hear colours and feel sounds. However, the most common type is coloured hearing (‘chromosthesia’), where patients can identify different sounds, voices or music as colours. Some synesthesia types have been linked to chemical agents and psychoactive drugs (e.g. LDS). Surprisingly, a study conducted by Simon Baron-Cohen in 1987 showed that patients tend to “feel” the same thing after stimulation with the same word over time. For example, the colour people would feel for the word ELEPHANT was gray, for SAILOR was blue-white and for SOLDIER was khaki, suggesting a connection to the actual colour of the word in the real world. A later study by Hochel and Milán (2008) showed that the letter ‘A’ produces a red colour, however, this is created internally and not seen as an actual red colour projecting in the vision of synesthetic people. Overall, each individual has unique, specific experience that is stable over time.
Even though this may sound intimidating, it was estimated that the prevalence of synesthesia is around 1-2% (in 2006), proposing that many more people may be synesthetes with undiagnosed, underlying symptoms. Nevertheless, people with synesthesia are functional and can live with it and even create art. A well-known musician suffering from synesthesia was the Russian pianist and composer Alexander Nikolayevich Scriabin (1872-1915). Scriabin was the main composer representing the Russian Symbolism, an artistic movement of the 19th century. Other synesthete-artists include Carol Steen, Anne Salz, Marcia Smilack and Brandy Gale.
***The image shows the musical notes ordered in the circle of fifth and coloured based on Scriabin’s colour spectrum.
