My wife and I recently came across a show that referenced a person who had the inability to visualize images in their minds. 

My immediate reaciton was, “Of course they can’t, nobody can.  We call those hallucinations.”  I thought it was absurd to suggest that people could just conjure up an image in their minds. 

Turn out, I’m the defective one: http://www.nytimes.com/2015/06/23/science/aphantasia-minds-eye-blind.html?_r=0

So in my case (which for 45 years I assumed was the same for everyone else), I can’t close my eyes and visualize say an apple.  If I see someone and close my eyes I won’t recall anything I just saw.  I couldn’t identify their shirt.   Unless I explicitly memorize it, I won’t remember a visual detail (like what my son’s glasses look like – I have no idea). 

To me, you close your eyes, it’s dark.  Sort of “Duh, of course.” 

I was aware that I could not easily recognize people.  Put one of my friends at the mall here and I wouldn’t recognize them easily.  But until the show we watched, I had no idea that people could actually visualize an image in their mind.  For me, it’s pretty mind blowing.