Synesthesia is a genetic condition that causes a mixing of the senses:
“I think it quite impossible to think of the date of a year without remembering and visualizing the figures”
“I have no recollection of my first synesthetic experience,
but by the age of 5 or 6 I was deliberately seeking out recordings to listen to in order to see the colors”
“When I taste something with an intense flavor, the feeling sweeps down my arm to my fingertips, and I perceive that object [weight, shape, texture, and temperature] as if I’m actually grasping it”