How many different types of synaesthesia are there?
This number is likely to be very big indeed. Not only do we have the pair-wise comparisons across the 5 senses (vision, hearing, touch, taste and smell) but we also types of synaesthesias within a single sense (e.g., seeing colours from viewing numbers). Additionally, there may be some types of synaesthesia that dont involve the senses at all (e.g., pairing letters/numbers with specific genders and personalities).
