I live with aphantasia, a condition where I can't visualize images in my mind. What it's like and how it affects my thinking.

• Mike Swanson learned he had aphantasia when he was 52.
• That means he can't picture anything in his brain, not even his wife's face.

This as-told-to essay is based on a conversation with Mike Swanson, a person who only recently discovered he has full aphantasia. It has been edited for length and clarity.

I am a person living with aphantasia, a condition that means I cannot picture images in my brain the way that other people can. This is what it has meant for me and why I don't think like other people.

I spent most of my life unaware that I was different because it never crossed my mind that people could see pictures in their heads.

I knew some things didn't connect with me, but I explained them away. When people talked about counting sheep to fall asleep, I said: 'it must be a metaphor, no one can visualize sheep in their head."

I thought flashbacks had to be a tool invented by filmmakers, not something people really experienced.

I was confused that people wouldn't like it if I mentioned gross things at the dinner table. I never knew it might conjure up unappetizing images for most people.

When I learned about aphantasia, at the age of 52, it was like a plot twist in a movie. Suddenly, things that were strange to me were cast in a new light.

Thinking in concepts, not in images

Aphantasia only got its name in 2015, after Dr. Adam Zeman, a neurosurgeon, discovered his patient lost the ability to see pictures in his head after a procedure.

Surveys suggest two to 4% of people have some form of aphantasia. As people talked about their experiences, it became clear that visualization exists on a spectrum.

On one side, you have people with hyperphantasia, who can recall images in vivid detail. On the other, you have people like me, who can't visualize a thing.

That means, for instance, there's no chance I could imagine my wife's face. I can recognize her if she walks in the room or spot her in a picture. I'll tell you the color of her eyes or hair. But it's more like a list of features, I don't remember any of that in a visual way.

So explaining her to a police sketch artist would be hilarious!

I also can't remember other senses, like smell or sound. If I ask people to think of their father talking to them, many would be able to hear his voice in their head. For me, the words are not even in a voice, they're just concepts.

Can you picture this ball on a table?

I often get asked: "how could you ever compare what's in my head to yours?"

Research is still in the early stages, although it already suggests that the brains and pupils of people with aphantasia react differently to images. There is no formal diagnosis of aphantasia and it is not recognized by the American Psychiatric Association.

But there are ways to assess how well you visualize, such as the Vividness of Visual Imagery Questionnaire.

When I'm at a dinner party, however, I prefer this simple test: imagine a ball on a table. Someone walks up to that table and pushes the ball. Now describe the scene.

In almost every conversation I have had, people will describe the ball in detail. "Oh, it is red. It's got a stripe and a star on it." They will say the table was oak, square, round, they'll talk about its color. They'll know the gender of the person and what they wore. Some of them will explain the whole scene as if a movie happened.

If you ask somebody like me, the ball is a concept, it doesn't have a color. The table is just a surface. At most, I might have thought about a hand interacting with the ball, not a full human. The ball fell off the table into the void. That's it. End of story.

Remembering in a different way

People with aphantasia usually remember in a slightly different way than visualizers. Because I can only recall things conceptually, just I have limits to how much I can remember. I can't picture myself in the future, or in the past.

That means if I misplaced my keys, I can't conjure up a picture of where I last saw them. After a conversation, I can't replay it in my brain, so I'll only remember what I took note of. If I'm back from vacation, I can't mentally transport myself there, only remember a list of what happened.

The upside is that people with aphantasia usually get over traumatic events more quickly — you're not haunted by negative memories.

My mom died when I was young, and I know that when I went through it at the time, it was a tragic experience. But I cannot relive it, despite any attempt I've made.

The downside, however, is that I can't see my mom's face. When I learned I had aphantasia, I couldn't believe that most people on this planet can visualize loved ones from their past. I felt terrible that I couldn't do that.

Doesn't change my life, but explains a lot

Knowing that I have aphantasia doesn't change much for me, but it has definitely caused me to think when I interact with somebody. I can't assume that they're hearing things the same way or understanding things the same way.

The only safe strategy then is to basically be adaptive. Don't assume they can visualize or conceptualize like you. If they're not connecting with your approach, try a different strategy.

It's certainly made me more sensitive at the dinner table. I now know I can plant a thought in your brain and you can't control it, visualizer! But it won't affect me at all. It's like a superpower.