Rather, both are perceived as separate and distinct.įor example, someone who perceives individual numerals as colors still sees the numerals in whatever color they are shown. Plus, in the types of synesthesia involving projected colors, those colors do not interfere with colors in the environment. Neither is simply a "swapping" of senses or the replacement of one sense with the next.
It must be explicitly pointed out that synesthesia is not a reaction which happens selectively or can be typically be "switched off - the synesthete cannot choose when to be synesthetic. There is, of course, some gray area between these two types of synesthesia, as there are synesthetes who describe their experiences in both a projected and associative manner, with the forms occurring both independently and in a mixed or concurrent fashion. In the above example, while a synesthete with associative synesthesia will not smell apples, they will feel a strong association between guitar's music and the smell of apples. Synesthetes who fall in this group feel the connection between a stimulus and a sense by which it is not normally perceived. The second major category is associative synesthesia. The smell of the apples is as real for the synesthete as the sound they are hearing. An example of this is a synesthete smelling apples whenever they hear a guitar playing a certain note. Firstly, there is projective synesthesia in which the synesthete hears, sees, feels, smells or tastes the second sensation which is triggered by the initial stimulus. There has also been at least one case in which a synesthete displayed a connection among all five senses.Īnother distinction among synesthetes is that their synesthesia can be bracketed into two major groups. Furthermore, while synesthesia is most commonly seen as a link between two senses, there are types of synesthesia in which three or more of the senses are involved. For instance, some synesthetes perceive words as a taste, while others may associate different personality traits with each of the 26 letters of the alphabet.
Someone with synesthesia is known as a synesthete, and there are over 80 combinations of ways in which a synesthete's senses may be linked. Both have contributed to the recognition, study and detailing of several types of synesthesia. The American Synesthesia Association points out that current "serious scientific attention" to synesthesia and heightened public awareness of the condition may be attributed to widespread internet use and new developments in the use of functional magnetic resonance imaging (fMRI) for detecting brain activity. For example, the music heard could trigger the perception of an orange-colored haze.Įvidence of synesthesia has been documented for centuries, but the condition has previously received little attention from the scientific community and the public-at-large. While there are many types of synesthesia, it is generally described as a phenomenon in which a person experiences a sensory stimulus, such as hearing a piece of music, and another of their senses simultaneously perceives the stimulus. What's it like to "taste" words or "see" music? If you know, then you might just have the sensory condition known as synesthesia.