Pseudosynaesthesia

Although the definition of synaesthesia is very specific, pseudosynaesthesia is seen frequently. Pseudosynaesthesia can occur unintentionally, as with drug use or learned associations, or intentionally, as in much literature, music, and art.

Drug Use

Drug use is one of the most common causes of pseudosynaesthesia. Hashish has been the most frequently mentioned substance in the past, due to the large number of writers who are known to have used it and commented on its vivid effects. These writers spoke frequently of hearing and/or smelling colors, seeing sounds, and even seeing feelings during their hashish intoxication. More recently, mescaline has been shown to produce extremely vivid pseudosynaesthetic experiences. Peyote (related to mescaline), which is sacred to many Native American tribes and is often used in their spiritual ceremonies, has very similar effects. With both peyote and mescaline, the pseudosynaesthesia produced is most frequently of the visual/hearing type.

Association

Another possible cause of pseudosynaesthesia is association. This theory has also been offered as an explanation of actual cases of synaesthesia, although this is very controversial. The theory proposes that, over the years, associations which frequently pair one sensation with another can lead to the automatic association of those two sensations even after the original pairing has been suspended.

The most common example of this involves colored letters. The idea here is that by playing with blocks that have colored letters on them, children may pick up the association between the letter and whatever color it is printed in. Also, since the words in children's books are often printed in color, the child may learn to associate a certain word or sound with a given color. This theory has many flaws though, most notably that the colors of letters and words that children may come in contact with are not usually the same color that the synaesthete later associates with the letter/word. In fact, children sometimes remark to their parents or teachers that "The colors on the blocks are all wrong", thereby exhibiting that their synaesthesia could not have been learned.

Another example commonly cited of synaesthesia-by-association is that of colored hearing. It is proposed that people may learn to identify, say, a trumpet with the color red because of the red color of a band's uniforms. The problems here are obvious. First of all, all musicians in the band would be wearing the same color of uniform, so why would the person not associate all instruments represented in the band with the color of the uniform? An argument might be that trumpets are one of the more distinguishable instruments in the band, but surely the percussion section is even more distinguishable most of the time. The other problem with this theory is that different bands obviously have different colored uniforms, yet the sound of a trumpet is quite frequently associated with the color scarlet or red in actual people with synaesthesia. How can this be explained, if the "synaesthesia" is merely an association?

Examples in the Arts

Following is a short list of several people who are either believed to have had synaesthesia or who incorporated it into their work, or perhaps even both. For more information on many of the listed individuals, click on the heading (literature, music, or visual media) that they are listed under.