I first read about synesthesia while reading an old science fiction novel during high school by the title “The Stars, My Destination,” or “Tiger! Tiger!” There is a scene in the book where, while trying to escape from an exploding interstellar prison, the protagonist is hit on the head by a support beam, making him experience a disorder known as synesthesia.
Synesthesia is a phenomenon where your senses join with other senses. For example, in the book this translated to the protagonist “feeling” colors and tasting noises. It lasted about ten minutes in the book, but the protagonist’s perception of the world around him was dramatically altered during this period. The book was correct in that a severe injury to the head seems to trigger this, although some people are born with different types.
Some people experience this in that concepts, numbers and names all have different colors associated with them. For example, the name “Charles” might have an inherently purple hue to the concept. "It is estimated that synesthesia could possibly be as prevalent as 1 in 23 persons across its range of variants" (Simner 1). I have prepared a video that will cover the basics of what this widely misunderstood sensation is.