People who have synaesthesia can do extraordinary things: see colors in numbers, see colors and hear music or taste words when they read or write. Notable people are Franz Liszt, Marilyn Monroe, Duke Ellington and Stevie Wonder to name but a few.
Scientists say it's due to their brains being cross-wired and sometimes after a stroke people experience it. They now consider that this may be beneficial in creating out-of-the box ideas and find it is more common in poets, artists and novelists.
A smell can evoke a memory; when I smell brandy snaps at Xmas I think of the first time I smelt death and how sickly sweet it was, almost like concentrated burnt sugar. Then, there's that elusive 6th sense, so often alluded to whenever you are alerted to danger or something doesn't seem quite right with your world.
When writing, I try to think of how all the senses come into play, useful recently when I wrote a murder scene and added a description of an unusual smell which had prompted the murderer to relive a memory.
If you had to assign one colour, smell or other sense to the people you know then what would they be and by consciously doing this, does it change your perspective of them?
I took the photo below last autumn while sitting in a hotel lobby. My son tapped me on the shoulder and then suddenly donned the mask he had just bought and he made me jump. But, as I looked into his eyes through the mask, my perception of him changed. He was no longer the teasing young boy who couldn't sit still for more than 5 minutes, he had an air of confidence and intrigue.