I can’t picture things in my mind. I didn’t realize that was unusual

People with aphantasia can't mentally visualize things. Mental imagery is a spectrum, and we lie outside it, in the dark

I discovered I had aphantasia by accident. When you live your entire life without a mind's eye", it seems completely normal to visualize nothing when remembering people and places, or imagining the future.

Two years ago, I wrote an article about pupillometry, or the measurement of a person's pupils to infer their cognitive state. Joel Pearson, a psychologist and neuroscientist at the University of New South Wales, was trying to use pupils as a biomarker to assess aphantasia, a condition thought to affect about 3.9% of people.