For the majority of us, the characteristics of things stay within their sensory categories. We do not see numbers with colours; we do not feel sounds; we do not taste shapes. People who have these strange mixing of the senses, synesthetes, are not that rare. For a long time, the idea of synesthesia was not accepted. Now, it has been shown over and over to be a real way of perceiving, individual to the person but stable and automatic.
Recently a few people have been found that see colour in response to various emotions. Ramachandran studied a man with this type of synesthesia. He saw a blue aura around a person which changes shade when particular emotions were sensed. The researchers placed a target person against a white background and drew a black line on the background around the person. The subject saw the blue aura in the space between the person and the black line. Blue or orange letters were projected onto the background and the subjects was timed in his identification of the letters. Blue letters inside the black line were identified slower than orange letters or blue letters outside the line. Blue letters against blue aura were more difficult to see. The researchers will be looking for cross-activation of V4 colour perception area and other areas (they hypothesis insular cortex, activated during subjective experience of emotion).
A Spanish group under Milan studied healers. One healer in particular, with a very good reputation, was clearly a face-colour synesthete seeing the aura of people, a touch-mirror synesthete who experience touch and pain when seeing it happen to someone else, and also a schizotypy personality tending towards slight paranoia and delusions. The researchers believed that the synesthesia encouraged the healers to believe in their own ability to heal other people, and their confidence caused a significant placebo effect in the healed people. However they believe that synesthesia is not an extrasensory power but a subjective and adorned perception of reality.
Oh well, educated people used to believe that meteorites and ball lightening were silly tales of the ignorant and superstitious. Now we are finding that near death experiences, ghosts and auras may have reasonable explanations and are not faked but simply not understood.