In 2003 a 65-year-old man brought a strange problem to neurologist Adam Zeman, now at the University of Exeter in England. The patient, later dubbed “MX,” claimed he could not conjure images of friends, family members or recently visited places. All his life, MX, a retired surveyor, had loved reading novels and had routinely drifted off to sleep visualizing buildings, loved ones and recent events. But after undergoing a procedure to open arteries in his heart, during which he probably suffered a minor stroke, his mind’s eye went blind. He could see normally, but he could not form pictures in his mind.

Zeman had never encountered anything like it and set out to learn more. He has since given the condition a name—aphantasia (phantasia means “imagination” in Greek). And he and others are exploring its neurological underpinnings.

An Unusual Blindness

Zeman and his colleagues began their analysis by testing MX’s visual imagination in several ways. Compared with control subjects, MX scored poorly on questionnaires assessing the ability to produce visual imagery. Surprisingly, though, he was able to accomplish tasks that typically involve visualization.

For example, when asked to say which is a lighter color of green—grass or pine trees—most people would decide by imagining both grass and tree and comparing them. MX correctly said that pine trees are darker than grass, but he insisted he had used no visual imagery to make the decision. “I just know the answer,” he said.

He also did fine on a test of the ability to rotate objects mentally. He was shown two pictures of three-dimensional objects and asked to say if they were the same item, pictured before and after being rotated on its axis, or different objects. Yet in contrast to the control group, he took longer to decide, and the time he took did not depend on the degree of rotation. In most people, the more that objects differ in their orientation, the longer it takes to mentally rotate them to see if they might match up.

Functional magnetic resonance imaging (fMRI) supported MX’s claimed inability to produce a mental image. Generally, when people are asked to visualize a person, place or object, a network consisting of various brain regions is activated. Some of them are involved in decision making, others in memory or vision. In MX, the visual regions showed very little activity, whereas those responsible for decision making and error prediction were more active. The finding suggested that MX used a different strategy than the controls did when tackling the visualization tasks.

An extensive literature search on the inability to form visual imagery offered little help in understanding MX. The first mention of this phenomenon was apparently Francis Galton’s “breakfast” study from 1880. The British naturalist asked 100 adult men to talk about the table at which they ate breakfast each morning. He requested information on the lighting, sharpness and color of the images in their head. Much to his astonishment, 12 of his subjects were unable to tell him much: they had assumed up to then that the phrase “mental imagery” was not meant literally.

Since 1880 other researchers had occasionally reported on people who had no ability to create mental imagery. Some had even conducted surveys to estimate the prevalence. In 2009 Bill Faw of Brewton-Parker College in Georgia reported that about 2 percent of the 2,500 people he queried reported having no visual imagination. But aphantasia itself attracted little research or public attention.

That began to change in 2010, after Zeman’s team published its study of MX. Discover magazine reported on the findings, leading a number of people to come forward, all saying they had never been able to create mental images, unlike MX, in whom the problem was new. Zeman and two colleagues then had 21 respondents answer questionnaires about their visual experiences, including one known as the Vividness of Visual Imagery Questionnaire (VVIQ).

They published the findings in 2015, using the name “aphantasia” for the first time. Most of the 21 said they realized only in adolescence and early adulthood (through conversations or reading) that other people could call up images in their mind. And although many of the respondents had dreams or flashes of visual imagery while awake, all were substantially or completely unable to purposely call up images in their mind, such as of past vacations or even their own wedding.

Since 2015 aphantasia has became the subject of newspaper articles, television reports, blogs and podcasts. A Facebook entry by American software developer Blake Ross, who helped to develop the Firefox browser, has been making the rounds. In it, Ross, too, describes his inability to create visual images. And several thousand have filled out the VVIQ, thanks in part to its posting by the BBC. It and another questionnaire are also posted at the Eye’s Mind Web page. Based on the first 700 or so surveys, Zeman estimates that aphantasia affects about 2 percent of the population, in line with Faw’s 2009 conclusion.

Relief in Numbers

Many people with aphantasia realized only after Zeman’s studies were published that there was such a thing as seeing with the mind’s eye. Many also found it comforting that there was now a name for something that distinguished them from others. They had found it hard to describe in words their inability to visualize. When they tried to explain, they were often met with incomprehension. Zeman was astonished at how grateful these people often were.

One of those who approached Zeman—Jonas Schlatter of Berlin—describes his own moment of discovery. Schlatter scored very low on the vividness questionnaire, which is viewed as strongly diagnostic of aphantasia. Like some of Galton’s study participants in the 1800s, Schlatter always thought that such expressions as “fading memories” or “let me paint you a picture” were simply turns of phrase. But then one evening at a house party, he came to understand that he was wrong. In the kitchen, he got into a conversation about how it could be that a person can simultaneously see something and create a mental image of it. The question initially seemed nonsensical to him, but he realized that he might differ from others in not making mental images. The next morning he began questioning his friends about their experiences and doing some Internet research. To his great surprise, he found that the ability to visualize images is real—except not for him.

When Schlatter first began to discuss his discovery with friends, he also learned that “people’s ability to synthesize images differs.” Zeman concurs. His 2015 study included 121 control subjects. Most of them showed a moderately good ability to visualize. But there were outliers at both ends of the scale, with more subjects falling at the high end than the low end. Zeman calls the above-average ability to create vivid images hyperphantasia.

Under the Hood

The research has raised a number of questions. One is whether aphantasia exists at all. Could people who think they are not making mental images simply be describing their images differently from the way other people do? After all, surveys elicit subjective descriptions, not objective measures of what is going on in the brain. Zeman admits that answers on the questionnaire are prone to a certain amount of error, but he is convinced that aphantasia actually occurs. For one thing, neurological findings such as those in the case of MX support that claim; for another, people who report lacking a mind’s eye sometimes have other anomalies related to visualization.

For example, some individuals with aphantasia report weakness in autobiographical memory, remembrance of events in their lives. In addition, many with aphantasia also suffer from prosopagnosia, impaired face recognition. To Zeman, the links to other conditions indicate that there may be several subgroups of aphantasia.

Joel Pearson, professor of cognitive neuroscience at the University of New South Wales in Australia, also considers aphantasia to be real. As part of his work, he studies binocular rivalry, a perceptual phenomenon that occurs when people are shown different images simultaneously to their left and their right eye. Here subjects do not see a combination of both images but rather only one at a time. Pearson and his team have discovered that a simple trick can influence which image is given priority. Asking volunteers to visualize one of the images before the test increases the probability that that image will come to the fore during the test. Yet self-diagnosed aphantasics are unaffected, indicating that visualization is impaired.

Zeman and others are also exploring how brain functioning differs in those with aphantasia. He and his colleagues recently invited more than 100 people to undergo a brain scan at his laboratory. They found that when individuals who scored high on the VVIQ were asked to visualize something, only a few brain areas became activated. Researchers have found that these regions light up when processing complex images, such as faces, events and spatial relationships. In contrast, more and different brain regions lit up in people who reported that they lack the ability to visualize. Those individuals tended to use regions associated with the control of behavior and planning, as was seen in MX.

Zeman has not yet studied extensively the other extreme, hyperphantasia. Many people with hyperphantasia have told him, however, that they easily lose themselves in daydreams about the past or the future. In contrast to aphantasia, hyperpahantasia has not yet been found to have links to face recognition or memory.

How Important Is the Ability to Visualize Imagery?

Zeman initially presumed that visualization was central to the creative process. Yet many of the people with aphantasia who contacted him work successfully in creative professions—as artists, architects and scientists. Jonas Schlatter, for example, creates Web sites for a start-up that he founded. His business partner thought it a bit odd that he used whiteboard, paper and a pencil in the design process. But Schlatter now understands that this approach is the only way that he can anticipate how the Web pages will eventually look.

How people deal with this condition differs from person to person. Some would like to learn to visualize. But no one has managed to do that yet, according to Zeman. Several test subjects have reported that they have been able to “see” with their eyes closed under the influence of hallucinogenic drugs. Schlatter, who does not feel especially disadvantaged by his aphantasia, has experimented with jumpstarting his mind’s eye in a less drastic way. “For two weeks I stared at the same pencil over and over again and tried to memorize it. But in the end I still couldn’t visualize it,” he says.

Fifteen years have passed since MX brought aphantasia to Adam Zeman’s attention. In contrast to Schlatter, who has been aphantasic for his entire life, MX did get back some of his ability to visualize. Presumably, his brain re-created connections that had been damaged by the stroke or built new connections. When MX dreams at night, he sees images. And occasionally, when someone mentions a place that he knows, an image pops up in his mind’s eye.