I remember the days of the classic video games. The days when the high-quality graphics actually were created within your mind. This was much like it was in the days of old-time radio, where your mind created the visuals that you were listening to on the radio.
Now, it seems like there is little room to create the visuals in your mind. TV and modern video games show exactly what everything looks like. Using the movies as a related example, everyone knows exactly what Han Solo looks like (I won't get into the whole "Han Shot First" controversy). But what if "Star Wars" only existed as a radio drama and as a series of books? What type of image would we have of each of the characters?