Mentally count the windows in your home. Did you close your eyes? Visualize your house’s layout in your head? I did, when I tried this task. But some people, researchers have discovered, seem to be incapable of producing and holding such images in their mind’s eye. (They’re also perfectly capable of answering the window question.)

In a paper published this month in the journal Cortex, researchers led by University of Exeter neurologist Adam Zeman have assigned this condition a name. They call it “aphantasia.” The word is a play on “phantasia,” a term Aristotle used to describe the mind’s capacity for producing images, as in memory (though there is some fascinating disagreement among scholars over whether this was Aristotle’s intended, or only, interpretation of the word). Zeman and his colleagues documented the first case of phantasia a few years ago, in a man they refer to as “MX.” MX had recently undergone a minor surgical procedure, only to find he could no longer produce mental images, whereafter he paid a visit to Zeman’s lab.

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Here’s where things get interesting. Zemam and his colleagues published the case study on MX in 2010. Science writer Carl Zimmer wrote about it for Discover Magazine. Soon thereafter, Zimmer started receiving emails from readers who claimed they too lacked the capacity for visual imagination. Zimmer forwarded the messages to Zeman, who turned the e-mailers into test-subjects by responding with a questionnaire. The results of the survey form the basis of Zeman’s team’s new report, which Zimmer describes in greater detail at The New York Times:

“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.

...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.

Zeman is also encouraging people who think they have aphantasia to e-mail him, at a.zeman@exeter.ac.uk.

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Read more about Zemam’s team’s questionnaire, and some of the aphantasic respondents they met while distributing it (most of whom can, puzzlingly, answer questions you would think require visual imagination), at NYT.


Contact the author at rtgonzalez@io9.com and @rtg0nzalez. Image Credit: agsandrew via Shutterstock.