In one of the most common forms of synesthesia, individual letters of the alphabet and numbers (collectively referred to as graphemes) are 'shaded' or 'tinged' with a color. Note the numbers 1-12 form an upside-down clock face. Grapheme–color synesthesia #Ī picture from the 2009 non-fiction book Wednesday Is Indigo Blue. While nearly every logically possible combination of experiences can occur, several types are more common than others. Synesthesia can occur between nearly any two senses or perceptual modes, and at least one synesthete, Solomon Shereshevsky, experienced synesthesia that linked all five senses. associative synesthesia: people who feel a very strong and involuntary connection between the stimulus and the sense that it triggers.įor example, in chromesthesia (sound to color), a projector may hear a trumpet, and see an orange triangle in space, while an associator might hear a trumpet, and think very strongly that it sounds 'orange'.projective synesthesia: people who see colors, forms, or shapes when stimulated (the widely understood version of synesthesia).

There are two overall forms of synesthesia: These are usually the first abstract concepts that educational systems require children to learn. This hypothesis – referred to as semantic vacuum hypothesis – explains why the most common forms of synesthesia are grapheme–color, spatial sequence, and number form. It has been suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the first time. Little is known about how synesthesia develops. Synesthetic associations can occur in any combination and any number of senses or cognitive pathways.

In spatial-sequence, or number form synesthesia, numbers, months of the year, or days of the week elicit precise locations in space (for example, 1980 may be 'farther away' than 1990), or may appear as a three-dimensional map (clockwise or counterclockwise). In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored.

Awareness of synesthetic perceptions varies from person to person. Synesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway.People who report a lifelong history of such experiences are known as synesthetes. The term Synesthesia comes from the Ancient Greek σύν syn, 'together', and αἴσθησις aisthēsis, 'sensation'.

Types of synthesia