Synaesthesia is a fascinatingly strange neurological condition in which two ore more senses are linked so that someone, for example, might "taste" sounds or "hear" colors. Now, researchers have confirmed a new kind of synaesthesia where individuals "hear" motion. In experiments conducted at the California Institute of Technology, synaesthetes heard beeps or taps when presented with visual flashes. From Scientific American Mind:
"I think of these people as having an enhanced soundtrack in life," (neuroscientist Melissa) Saenz says. Her team is conducting brain-imaging studies to try to tease out the roots of that soundtrack as well as how a typical brain combines visual and auditory signals to improve perception.
Hearing-motion synaesthesia (SciAm Mind)