Welcome to the quantum science podcast. Each episode we bring you stories about developments

in science and mathematics. I'm Susan Vallett. Neuroscience research into people with

Afantasia, who don't experience mental imagery, is revealing how imagination works and demonstrating the sweeping variety in our

subjective experiences.

That's next.

It's season three of the joy of why, and I still have a lot of questions.

Like, what is this thing we call time? Why does altruism exist?

And where is Jan 11? I'm here. Astrophysicist and co-host. Ready for anything. That's right.

I'm bringing in the A team. So brace yourselves. Get ready to learn. I'm Janelleleven. I'm Steve

Strogatz. And this is Quantum Magazine's podcast, The Joy of Why. New episodes drop every other Thursday.

A couple of years ago, Sarah Schaumstein realized she didn't have a mind's eye. The vision scientist was sitting in a seminar room,

listening to a scientific talk when the presenter asked the audience to use their imagination.

Imagine an apple, close your eyes, and then report in terms of vividness, how vivid is your

image. And I closed my eyes. And I imagined an apple, just like I know that I can imagine things.

And I was like, I imagine an apple. That was great, but it was completely black.

But I imagined an apple. I can tell you everything about it, right?

Schaumstein was confused. How come she didn't actually see an apple?

Most of her colleagues reacted differently. They reported

actually seeing an apple, some vividly and some faintly, floating like a hologram in front of them.

In that moment, Shamstein, who's spent years researching perception at George Washington University,

realized she experienced the world differently than others.

They said black. I mentalize, but I don't visualize. So that was how I discovered that I had

...