Picture this—if you can.
About five years ago, Professor of Cognitive Neuroscience Sarah Shomstein attended a brown bag research lunch hosted by the George Washington University Department of Psychological and Brain Sciences.
During a graduate student’s presentation on perception, the audience of faculty and students were asked to close their eyes and imagine a green apple. After a few moments, the student instructed them to rate how vividly they pictured the apple in their mind—from detailed colorful hues to pitch-black nothingness.
As her colleagues described seeing shades of light across the apple’s pale green skin, Shomstein, the Thelma Hunt Professor of Cognitive Neuroscience and now the chair of the department at the Columbian College of Arts and Sciences, was confused. What were they all talking about?
“I didn’t see anything,” she recalled.
Shomstein could describe an apple. She knew its shape, its texture, its taste. But when she tried to picture one in her mind, she said, “It was just…black.”
It’s a phenomenon known as aphantasia, an inability to bring an image to mind in visual form. And it may affect more than 2 percent of the population—including Shomstein who, ironically, is a renowned perception scientist and once dismissed aphantasia as “baloney.”
“I was skeptical,” she laughed. “I thought people were making it up.”
Some call it a variant, some call it a phenomenon. Either way, little is known about aphantasia. It was identified less than a decade ago when neurologists named it after Aristotle’s term “phantasia”—or “mind’s eye.” Early research indicates that it may involve weak connections between the regions of the brain that control vision and memory. (A cousin occurrence called hyperphantasia seems to be an opposite phenomenon where people experience extra vivid mental imagery.)
Scientists agree that aphantasia doesn’t appear to be a cognitive deficit. It doesn’t seem to interfere with perception or memory and so far hasn’t translated to any difficulties with other behaviors.
And while aphantasia has made Shomstein a hit at campfires and conferences when she plays the green apple game with astonished friends and colleagues, it’s also spurred her research curiosity.
The head of GW’s Attention and Cognition Laboratory and a fellow of both the Association for Psychological Science and the international Psychonomic Society, Shomstein has led research on how the human brain processes images. Her work doesn’t directly relate to aphantasia, but she’s consulted with other perception experts about collaborating on projects to understand what goes on inside aphantasic brains.
“The fascinating thing is we don’t really know” the answer, she said. “I’m a perception scientist with aphantasia. And I don’t know what’s happening inside my brain.”
Traffic on the neural highway
Clues may lie somewhere along the brain’s labyrinth pathways. Shomstein explained that there are different neural routes for seeing objects and imagining—or “mentalizing,” a term Shomstein prefers.
During sight, neural signals travel from the light our eyes pick up to the back of our brains where they are processed in the visual cortex. That information then flows forward to the region which controls memory, essentially allowing us to understand the object we’re looking at.
But imagination travels in the opposite direction. Think, for example, of the last time you ate at a restaurant. You can bring to mind the smell and taste of the food and the sounds around you. But you’re not looking at an image. As Shomstein explains, you are pulling memories using your frontal cortex and engaging memory structures. “This is not visual. It’s not sensory or auditory. It is conceptual,” she said. While imagining the restaurant, that conceptual “baggage,” as Shomstein puts it, travels backward in the brain to the visual cortex where it is reconstructed as an image.
Seemingly, an aphantasic brain would have an issue in the visual cortex. But early imaging studies show that the cortex fires normally. For some reason, Shomstein hypothesizes, in aphantasia the visual cortex simply refuses to perform its role in the imagination chain. “The memories are brought together but then the visual cortex, which is working just fine, never contributes,” she said.
Nevertheless, researchers are drawing a picture of aphantasia that looks different for different people. Some seem to have been born with it while others said their visual imagery has changed over time. Most dream in images, some can’t. Some report weak autobiographical memories and some experience flashes of mental imagery.
For her part, Shomstein believes she has always experienced aphantasia—even when she didn’t know it. “This is the way I have always imagined things,” she said. And she is equally astonished by people who experience vivid imagery. “It’s mind-boggling to me,” she laughed. “Don’t you get confused? How do you know what’s real?”
Her own research—much of which centers on how our brains process and interact with the visual environment—isn’t actually affected by aphantasia. As she teaches in her cognitive neuroscience classes, mental representations are as dependent on knowledge and experience as they are visual imagery. “My research transcends whether you can create images [in your mind] or not,” she said. “If you have a concept [of an object], whether it comes with an image doesn't matter.”
Meanwhile, Shomstein has been inundated with emails by her fellow aphantasiacs. She’s heard from chemists, physicists and artists who say her experience has opened their own minds’ eye.
In fact, Shomstein suggests her way of seeing things may be a benefit. She cited speculation that academics may have a higher prevalence of aphantasia—perhaps finding greater mental focus without visual distractions.
“If I can do everything you can do without the image,” she said, “then why have it?”