Are there any advantages or disadvantages to having synaesthesia?
Synaesthesia has no known effects on IQ and synaesthetes do not stand out from other members of society in any way – it is quite possible that you have acquaintances who are synaesthetic without even realising it. Most synaesthetes could not imagine life without their experiences and are either positively disposed towards it (“I feel so sorry for people who don’t have this”), or neutral (“it is like being asked whether you enjoy having a left arm – it is just there, and I neither like it nor dislike it”).
For some people, however, synaesthetic perceptions can be intrusive and disrupt their chain of thought if they have a particularly intense sensation. Synaesthesia may have some benefits on memory. One of the most famous synaesthetes, Shereshevsky (Luria, 1966), actually made a living out of being a memory expert! We have recently shown that many synaesthetes have better memory for things in which their synaesthetic colours are involved (Yaro & Ward, 2007). Synaesthetes also have more finely tuned colour perception (Yaro & Ward, 2007). They report being good at learning languages, but this could possibly be related to the known benefits to memory. On the negative side, many synaesthetes report having difficulties with numbers and get left/right confused. ^