View full lesson: http://ed.ted.com/lessons/what-color-is-tuesday-exploring-synesthesia-richard-e-cytowic

How does one experience synesthesia -- the neurological trait that combines two or more senses? Synesthetes may taste the number 9 or attach a color to each day of the week. Richard E. Cytowic explains the fascinating world of entangled senses and why we may all have just a touch of synesthesia.

Lesson by Richard E. Cytowic, animation by TED-Ed.