1. Synesthesia: synesthesia is a condition in which one sense (for example, hearing) is simultaneously perceived as if by one or more additional senses such as sight. Another form of synesthesia joins objects such as letters, shapes, numbers or people's names with a sensory perception such as smell, color or flavor. The word synesthesia comes from two Greek words, syn (together) and aisthesis (perception). (http://faculty.washington.edu/chudler/syne.html )
2. grapheme-color synesthesia: is a form of synesthesia in which an individual's perception of numbers and letters is associated with the experience of colors. Like all forms of synesthesia, grapheme → color synesthesia is involuntary, consistent, and memorable.( http://en.wikipedia.org/wiki/Grapheme–color_synesthesia )
3. ordinal-linguistic personification : is a form of synesthesia in which ordered sequences, such as ordinal numbers, days, months and letters are associated with personalities (Simner & Hubbard 2006). ( http://en.wikipedia.org/wiki/Ordinal_linguistic_personification )
4. number-form synesthesia: is a mental map of numbers, which automatically and involuntarily appears whenever someone who experiences number-forms thinks of numbers. (http://en.wikipedia.org/wiki/Number_form )
5. sound-color synesthesia: ndividuals experience colours as a response to music/sounds. Sound–>colour synesthesia can be further broken down into two categories, “Narrow band” and“Broad band”. ( http://undacovabear.wordpress.com/2009/02/08/sound-colour-synesthesia/)
6. lexical-gustatory synesthesia: is one of the rarer forms of synesthesia, in which spoken or written words evoke vivid sensations of taste, sometimes including temperature and texture. (http://en.wikipedia.org/wiki/Lexical-gustatory_synesthesia )
