Lesson 2: Unique Disorders

Synesthesia

Synesthesia is a condition in which one sense, touch for example, is simultaneously perceived by one or more additional senses such as taste. Although individuals with synesthesia may not act abnormally, they experience sensory stimulation unlike most of the population. An example might be when a person touches a wool sock and “tastes” chocolate. Another example might be when a person hears a doorbell and sees the colour blue. Synesthesia is derived from two Greek words – syn (meaning together) and aisthesis (meaning perception). Synesthesia, therefore, can be thought of as joined perception.

Synesthesia can involve any of the five senses (sight, sound, taste, touch, smell), but the most common combination is the joining of specific colours with numbers or letters. For example, a person with synesthesia may see the number three as light green and the letter “d” as orange. Entire words may have a colour as well – the word “me” may be thought of as red or each letter (m and e) may be a different colour.

Synesthesia example: me

Diagnosing synesthesia is not easy;– there is no set standard for individuals to use as a guide. Overall, perceptions should meet the following criteria.

Perceptions are
- involuntary
- not caused by imagining a sensation in the “mind’s eye”
- consistent (Perceptions of identical experiences must be the same each time; for example, dogs are always blue.)
- generic and not complex (such as seeing shapes but not details in the shapes)
- memorable (e.g., A friend’s pet dog named Fido is remembered as blue the colour he was associated with, not as Fido – his name.)

Synesthesia is thought to have a genetic link because it is often found in members of the same family across generations. Synesthesia involves unusual processing of sensory data in the brain, and it is more common in women.