Derek Amato

(via Flickr/jtbrennan)

Synesthesia is a complex and rare condition in which input from one sense is perceived through another sense.

The abilities of people to see what they hear or hear what they see are just two examples.

A significant amount of research into the condition is being conducted at the University of Missouri–St. Louis.

"St. Louis on the Air" host Don Marsh spoke with UMSL philosophy professor Brit Brogaard and with UMSL philosophy graduate student Kristian Marlow, who participated in the research.

Also joining the program were two synesthetes: