It’s nearly three years since Professor Adam Zeman helped to introduce the world to a new species of brain condition. Yet the letters and emails from people who believe they have aphantasia – an inability to summon images to the mind’s eye – have barely stopped arriving since.
Sack-loads of mail, amounting to some 12,000 reported cases, have built up at his University of Exeter Medical School base.
This is despite there previously being only sporadic published examples from history of people unable to voluntarily picture things in their mind.
Zeman, a professor of cognitive and behavioural neurology, is now investigating various avenues related to the phenomenon, including a possible link to brain injuries and neurological conditions.
“The most common cause for not having a mind’s eye is being born that way, but there are examples in literature describing people losing it through some form of brain injury,” he says.
The first reported case of visual imagery loss due to brain injury was publicised in 1883 (Charcot & Bernard). A much later study (Farah, 1984) concluded that the vividness of self-reported visual imagery can be dimmed by a brain injury.
It can also vary widely among healthy individuals (McKelvie 1995), and be affected by depression, anxiety and “depersonalisation” (Sierra, 2009).
Zeman says: “I’m keen to revisit Farah’s work in particular to assess what is happening in brains that have been damaged in such a way that they can no longer visualise.
“We want to work out whether there are common areas of the brain or processes affected. We don’t yet know what the proportion of people with brain injuries with aphantasia is, but it would need to be a moderately bad brain injury to either cause focal brain damage or damage to some connections.
“On the other hand, it obviously couldn’t be so severe that the person can’t notice or describe what has happened.”
Studies into mental imagery were pioneered by Francis Galton who, in 1880, published evidence of a wide variation in subjective vividness among survey respondents; some participants described no power of visualising, he reported.
Over a century later, a study showed that 2.1 to 2.7 per cent of general population participants claimed no visual imagination (Faw, 2009).
Zeman and fellow researchers coined the term aphantasia based on the classical Greek word for imagination, phantasia, defined by Aristotle as the faculty/power by which a phantasm, is presented to us.
In 2010 they reported a particularly pure case of imagery generation disorder
(Zeman et al., 2010). A 65-year-old man had become unable to summon images to his mind’s eye following a coronary angioplasty.
The subsequent paper was picked up by the popular science periodical Discover, prompting people with similar experiences to make contact.
These 21 individuals had a lifelong reduction of visual imagery and were analysed via a questionnaire (Zeman, Dewa & Della Sala, 2015).
The results, published in 2015, delivered several interesting findings. While respondents could not visualise when prompted by the questionnaire, most reported that they experienced involuntary imagery.
These usually occurred in dreams or in the form of ‘flashes’ during sleep onset. Most respondents didn’t become aware of their condition until their teens or 20s; it was only in conversation or through reading that they’d stumbled upon the fact that most people can visualise in their minds eye.
This new proof of an inability to voluntarily visualise caught the world’s attention and triggered a fresh wave of letters and emails from hundreds, and then thousands, of people with potential aphantasia.
Work is now underway to gain deeper insights into the condition. Questionnaire responses have been elicited from 2,000 more cases, while a separate study involves brain imaging and neuropsychology comparisons between groups with low, moderate and very vivid mind’s eye imagery.
The results of both aspects of the research are expected to be published later this year.
“We have a mountain of data and are trying to work out whether aphantasia comes in different shapes and sizes, which we think it does. It’s associated with problems related to autobiographical memory and, in some cases, with autistic spectrum disorder. So there are lots of subgroups.
“Of course, prosopagnosia [an inability to recognise faces] and autobiographical memory problems can occur through brain injury, and we’ve had around 50 individuals contact us whose aphantasia was seemingly caused by brain injury, stroke or meningitis, and we want to look at them more closely.”
Investigations into the root causes of aphantasia, and how it impacts on individuals, require the factoring in of multiple regions of the brain.
“Visualising involves a network of brain regions. To visualise you have to make a conscious decision to do so. This involves the decision-making regions in the front and parietal lobes. Visualisation also involves memory-related regions if you are visualising something you encountered in the past which is stored in your memory.
“Then you also activate visual areas; we know from functional imaging that people do use visual areas of the brain to visualise.”
While acquired aphantasia may be thought of as a condition, causing various challenges such as facial recognition problems, for people with lifelong aphantasia it is merely considered a different way of experiencing life.
“Lifelong aphantasia is not a disorder. People’s experience may be different from the rest of us but it is not an illness. You can lead a completely normal, fulfilling, productive life without having imagery. If you have a mind’s eye and you lose it, that’s different and it seems natural in that case to call it a disorder.”
Aphantasia may even help, rather than hinder, some people, with a strange correlation existing between a lack of mental imagery and high achievement.
Oliver Sacks, the late neurologist, naturalist and author whose bestselling case histories on disorders were adapted for the stage, big screen and fine art exhibitions, had no mind’s eye.
Nor does Craig Venter, who pioneered the decoding of the human genome. Famously, Blake Ross, co-creator of the Firefox web browser, had an aphantasia-infused awakening in 2016 and documented it on Facebook.
“I just learned something about you and it’s blowing my goddamned mind,” he wrote.
“This is not a joke…It is as close to an honest to goodness revelation as I will ever live in the flesh. Here it is: You can visualise things in your mind.”
Zeman says: “There seems to be a relationship between aphantasia and being involved in mathematical, computational and scientific types of activity. Perhaps this is an interesting way of putting it, but maybe not having your head cluttered by visual images is helpful if you want to think in an abstract way.
“It’s a bit of an open question whether it can help creativity. Certainly, it does seem that not having much visual imagery biases people towards becoming involved in abstract mathematical and computational professions. That is an empirical fact from our survey data.
“We’ve found that people with low imagery are likely to be in those sorts of roles, whereas people with high imagery are more likely to be in what are typically regarded as creative pursuits, such as painting or writing a novel.”
At the same time, people considered creative appear to be more prone to being affected by the acquired version of the condition – or at least noticing the limitations it can cause.
“It is generally true among those who have lost their mind’s eye, perhaps following stroke, brain injury or meningitis, that they were very visual to start with. Artists and other people who take a particular interest in the visual world and visual experience are clearly going to notice if something changes.
“For example, a chap came to see me who had gradually lost his mind’s eye over two to three years, possibly as part of the start of a neurological degenerative disorder. He was a photographer and spent a lot of time visualising things in his mind’s eye, so he noticed the change.”
Loss of mental imagery does not equate to loss of imagination, however. “It’s hard to define imagination, but it involves being able to detach yourself from the here and now and things that aren’t present in a more or less creative way.
“For most of us, visualisation is an important part of the imagination because most of us think visually to some degree. But there are other ways of thinking, for example you can use language very imaginatively without being able to visualise or you can use your auditory imagination – things in your mind’s ear – and imagine movements, such as dancing.
“So, visual imagination is important to most of us because vision is pretty important, but it is certainly not the only way to represent things that are not present to us.”
Read more about aphantasia
Professor Zeman is pursuing the study of aphantasia through an interdisciplinary project. Click here for more
Read his initial blog article about the subject here
Here’s how Firefox founder Blake Ross shared his discovery of aphantasia
The Discover magazine article which helped to bring the world’s attention to aphantasia