This is Science Quickly, a podcast from Scientific American.

I'm Stefan Amontali.

If I asked you to visualize, say, Harry Potter, you'd probably have no problem picturing

him in your mind.

A teenage wizard with black hair, glasses, a thunderbolt-shaped scar on his forehead,

and a wand in his hand.

It would almost be as if you were pulling up a photograph in your head.

This ability to visualize is often called the mind's eye, and most people would say it's

as inherent as breathing.

But it turns out that's not quite true.

Estimates say about 1% of the population live with an extreme form of a condition called

aphantasia.

Those who have it can't visualize anything in their head.

So when they try and imagine that think about what an apple looks like, it's just nothing.

It's black on black.

For example, when I think about an apple, I can catch up a conscious experience of an

apple.

I can see a stem.

I can see a leaf.

I can see a drop of water on there.

It's not like holding an apple in my hand, but I have an experience of an apple.

Joel Pearson is a professor of cognitive neuroscience and director of the Future Minds lab at the University

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