Picture This? Some Just Can’t

Certain people, researchers have discovered, can’t summon up mental images — it’s as if their mind’s eye is blind. This month in the journal Cortex, the condition received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents visual imagery to our minds.

I find research like this irresistible. It coaxes me to think about ways to experience life that are radically different from my own, and it offers clues to how the mind works.

And in this instance, I played a small part in the discovery.

In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School. After a minor surgical procedure, the man — whom Dr. Zeman and his colleagues refer to as MX — suddenly realized he could no longer conjure images in his mind.

Dr. Zeman couldn’t find any description of such a condition in medical literature. But he found MX’s case intriguing. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future.

MX agreed to a series of examinations. He proved to have a good memory for a man of his age, and he performed well on problem-solving tests. His only unusual mental feature was an inability to see mental images.

Dr. Zeman and his colleagues then scanned MX’s brain as he performed certain tasks. First, MX looked at faces of famous people and named them. The scientists found that certain regions of his brain became active, the same ones that become active in other people who look at faces.

Then the scientists showed names to MX and asked him to picture their faces. In normal brains, some of those face-recognition regions again become active. In MX’s brain, none of them did.

Paradoxically, though, MX could answer questions that would seem to require a working mind’s eye. He could tell the scientists the color of Tony Blair’s eyes, for example, and name the letters of the alphabet that have low-hanging tails, like g and j. These tests suggested his brain used some alternate strategy to solve visual problems.

After I came across the case study of MX in 2010, I wrote about it. And then something remarkable happened: I discovered that MX was not alone.

“I have spent my entire life explaining to people that I do not think visually,” one reader wrote to me. “I cannot conjure a mental image of a person or of a place to save my life.”

As more emails arrived, I did the only thing I could think to do: I forwarded them to Dr. Zeman. It turned out that he and his colleagues were also hearing from people who thought they had the condition.

The scientists decided to make a formal study of their email correspondents. They replied to emails with a questionnaire designed to probe the mind’s eye. All told, the researchers have received 21 responses.

Among the questions, the scientists asked their subjects to picture things like a sunrise. Try as they might, most of the respondents couldn’t see anything. But some of them did report rare, involuntary flashes of imagery. The mention of a friend’s name, for instance, might briefly summon a face.

When the scientists asked their subjects to mentally count the windows in their house or apartment, 14 succeeded. They seem to share MX’s ability to use alternate strategies to get around the lack of a mind’s eye.

All in all, Dr. Zeman and his colleagues were struck by how similar the results of the survey were.

“These people seemed to be describing something consistent,” Dr. Zeman said. Rather than being a unique case, MX may belong to an unrecognized group of people.

In their new report, the scientists note that many of the survey respondents differed from MX in an important way. While he originally had a mind’s eye, they never did. If aphantasia is real, it is possible that injury causes some cases while others begin at birth.

Thomas Ebeyer, a 25-year-old Canadian student, discovered his condition four years ago while talking with a girlfriend. He was shocked that she could remember what a friend had been wearing a year before.

She replied that she could see a picture of it in her mind.

“I had no idea what she was talking about,” he said in an interview. Mr. Ebeyer was surprised to discover that everyone he knew could summon images to their minds. Last year, someone showed him my article about MX.

“I’d been searching forever on Google, but I didn’t know what to look for,” he said. “It was really empowering just to hear a story of someone else who had it.”

Mr. Ebeyer got in touch with Dr. Zeman, who sent him the questionnaire. Like many other subjects, he could count his windows without actually picturing his house.

“It’s weird and hard to explain,” he said. “I know the facts. I know where the windows are.”

The new study has brought Mr. Ebeyer some relief. “There’s something I can call this now,” he said.

Dr. Zeman now wonders just how common aphantasia is. “Moderately rare” is his guess, but to follow up, he has sent the questionnaire to thousands of people in Exeter.

He hopes to find enough people with the condition to begin a bigger scanning study, comparing their brains with those of people who see vivid mental images. Together, they may reveal more than MX could on his own.

Speaking of which — Dr. Zeman said that he was interested in meeting more people with aphantasia. He can be reached at a.zeman@exeter.ac.uk.