If you haven't heard of the condition "aphantasia" before, you should definitely read this Facebook post by programmer, writer, and Mozilla co-founder Blake Ross. The word means the "absence of fantasy" and individuals who have aphantasia literally can't visualize the world.
"If I tell you to imagine a beach, you can picture the golden sand and turquoise waves. If I ask for a red triangle, your mind gets to drawing. And mom’s face? Of course," writes Ross. "I don’t. I have never visualized anything in my entire life. I can’t 'see' my father’s face or a bouncing blue ball, my childhood bedroom or the run I went on ten minutes ago. I thought 'counting sheep' was a metaphor. I’m 30 years old and I never knew a human could do any of this. And it is blowing my goddamned mind."
"I’m 30 years old and I never knew a human could do any of this."
The post is long, engaging, and eloquent. Ross described how he found out he had the condition after reading a New York Times article about a man who lost his ability to form mental images after surgery. ("What do you mean "lost" his ability? I thought. Shouldn’t we be amazed he ever had that ability?") He then talked to his friends to confirm what was going on, and the essay includes snippets of their conversations as well as answers to various questions he's fielded. (e.g., "What is going through your mind all day, if not sights and sounds?"; answer — "All narration, all the time.")
Ironically, it's quite tough to imagine what it's like to have your imagination restricted in this way. Ross's essay, though, explains it as clearly as anything I've read before. And who knows, perhaps sharing it will lead to a few more aphantasiacs out there having revelations of their own.