A synaesthete often see's a colour projected outside their "minds eye". A non-synaesthete would merely perceive a colour or object or taste within their "minds eye".

A synaesthete's perceptions are normally only one way. I get tastes from words but I cannot automatically perceive a word when given a taste. There have however been a few rare cases where the synaesthetic perceptions have been bi-directional.

A synaesthete's perceptions are often thought to cause fairly strong emotional reactions, usually pleasurable but they have been known to be unpleasant in some cases.

A synaesthetic perception is quite often far more memorable than the initial "normal" perception. For me, asked to remember a person called Sarah, I more readily associate the taste of warm Cream Soda to the person than I would her given name!