When you close your eyes, what do you see? For me, it’s always been a black screen, sometimes with the static of a crackling TV. My dreams are tangles of thoughts, but when I try to remember them, I can’t actually see anything. I don’t need to pinch myself to see if I’m dreaming, because my dreams never resemble reality. I have a condition called aphantasia, mind blindness. I can see clearly with my eyes but not in my mind.

When I think of a memory, I can conceptually understand and answer questions about it, but cannot project it into my mind or imagine myself in it. I hold all the projector slides and have all the information, but can’t see the actual picture. Four percent of people are estimated to experience aphantasia, but we can go our whole lives without knowing we have it.

I only realized when I was 21, sitting at a coffee shop with my best friend. She animatedly spoke about an article she had read on aphantasia and how she couldn’t imagine what it would feel like. Suddenly, I realized that I saw the world differently. I had always assumed that daydreaming, counting sheep, and picturing myself on a beach were metaphors. I couldn’t imagine what mental imagery would feel like.

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After telling my family, we discovered that my mom has it too. Aphantasia is familial, with research showing that if you have congenital aphantasia, there is a 21% chance that your first-degree relative (parent, sibling, or child) will also have it. At first, it was hard to not see this as a loss, but over time, I’ve developed a new appreciation and interest in how I learn and experience the world.

The concept of aphantasia traces back to Aristotle, who described a sixth sense of visual imagination called phantasia. Aphantasia indicates the absence of mental imagery, but about 10% to 15% of people are at the other end of the spectrum with extremely vivid imagery or photographic memories, which is called hyperphantasia. Even though knowledge of these invisible differences in cognition dates back to 340 B.C., both terms were only named by Dr. Adam Zeman, professor of cognitive and behavioral neurology at the University of Exeter in the U.K., in 2015.

Mental imagery, as a research topic, was considered taboo in the second half of the 20th century because of behaviorism, which rejected introspection as a way to understand behavior. Now, however, “It’s been embraced by scientists of all types now because we can measure it. People are realizing that we don’t know much about it, and we should,” says Joel Pearson, professor of cognitive neuroscience at the University of New South Wales in Australia.

The experience of having aphantasia is difficult to describe because it varies from person to person and there is no conscious equivalent. “People say that they feel that the imagery is there but they just can’t get to it,” Zeman says. “We know that, in a certain sense, [people with aphantasia] must have a very detailed knowledge of how things look because [they] can recognize them. The sensory information is all in the brain [but they find it] hard to use that information to produce a visual experience in the absence of the item.”

Aphantasia is often described as a visual condition, but it’s actually multisensory. People who experience a lack of mental imagery can have a reduced capacity to access other mental senses (imagining sound, movement, smell, taste, and touch). For example, I am unable to imagine most senses. I cannot conceptualize the taste of my favorite meal or the feeling of a hug, but have a strong inner voice and can hear and remember songs in my mind. This makes me a multisensory aphantasic, since I have a reduced mental ability across more than one sense, but not all.

Some people experience a complete absence of mental senses, which Zeman refers to as global aphantasia. In a 2020 research study published in Scientific Reports, only 26% of aphantasic participants reported no internal mental representations, which shows that most aphantasics experience unique combinations of the other senses. Even though people with aphantasia share a lack of voluntary visual imagery, we cannot assume that everyone has the same experience.

Scientists have primarily studied aphantasia in terms of visual imagination, instead of other senses, so a lot is still unknown. Even among visual aphantasics, people can have completely different experiences—some have no concept of visual imagery, but 63% can see vivid images in their dreams. “Most people with aphantasia are pretty confident that they do dream visually. It’s just that they’re experiencing it in a brain state that’s involuntary,” Zeman says.

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There are advantages and disadvantages to having aphantasia. People with aphantasia tend to have a higher average IQ (115 compared to the 110 score of the general population) and are less affected by scary stories since they cannot visualize them. As Zeman explains, “it’s clearly not a bar to high achievement … You might have thought it would interfere with creativity, but that clearly isn’t the case either.”

Aphantasics experience lower levels of sensory sensitivity, overwhelm from “sensory inputs that might be bright lights, loud noises, or the smell of perfume,” says Carla Dance, a doctoral researcher at the University of Sussex in the U.K. Despite this, they do have more difficulty with autobiographical memory and face recognition.

People may not realize they have aphantasia because they’ve developed shortcuts for how to process the world. “In visual working memory, we see their performance is about the same [as the general population]. But once you start looking under the hood and see how people are holding this information in memory, it’s a different mechanism and a different strategy, even though the performance on everyday tasks looks the same,” Pearson says. “Most people with aphantasia will have very good spatial skills … but they can’t put any objects into that space.”

At work, in an exercise to explore neurodiversity, my colleagues and I were once asked to draw our brains to visualize the way we think, but I couldn’t do it, because I don’t think in images. I felt frustrated and self-conscious, because there was no alternative for me to participate—I had to sit and wait while other people completed the exercise. I was reminded of a way in which I’m different from others, even though I don’t like to see it as a weakness. There are easy ways to work around this and be inclusive of people who think differently. For example, my coworkers could have reframed the exercise from drawing what our minds look like to simply representing how we think. That way, I could have written a list of words or emotions to explain how my mind works, rather than trying to come up with images.

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“Aphantasia is just another way of experiencing the world. It comes down to figuring out what learning style you have and what works for you, given your imagery profile,” Dance says. “If somebody has really good auditory imagery, perhaps [they can use] that sense as a gateway to remembering things.” We can all benefit from deeply considering how we think and what this tells us about ourselves.