Most people are able to picture things in their mind - to recall images of places and people they have seen. But a small minority of people have something called "aphantasia." It means you don't conjure images in your imagination. You have no "mind's eye." Freelance contributor Alison Motluk explored this idea in a special feature.

She spoke with Dr. Adam Zeman, Professor of Cognitive and Behavioural Neurology at the University of Exeter. He first accidentally discovered the condition in a patient a few years ago whom he believed was unique. But after a magazine article about the patient appeared, thousands more people wrote to him about having the same experience.

John Chew lives in Toronto, and only discovered that he also had aphantasia after reading about it on the BBC web site.

More surprisingly, Toronto fantasy fiction author Michelle Sagara also has aphantasia - but still manages to write fiction that is filled with descriptive passages that she is unable to imagine in her own mind.

Related Links:

- Dr. Zeman's paper in the journal Cortex
- Blake Ross, founder of Firefox, describes his discovery of his own aphantasia​
- NY Times article on aphantasia