People often develop synesthesia

The traditional model of our mental function has been that the senses provide separate data to our brain which are then translated into the appropriate mental phenomena:visual images into trees, auditory experiences into bird songs, and so on.But occasionally, we have come across people whose senses seem to mingle together,allowing them to hear colors,
or taste sounds.Until recently, the common understanding
was that this phenomenon,called synesthesia,was a direct connection between the parts of the brain responsible for sensory stimuli such as seeing the color yellow immediately
upon hearing the tone of b flat.