Imagine a Christmas tree. Or try to visualize in your mind the last meal you ate yesterday. Recall the face of a family member you haven’t seen in a while. Surely, the majority of us are able to evoke these mental images without a problem, perhaps to varying levels of precision and detail, but with the same fluidity with which we recall objects, people and lived experiences every day of our lives. But a certain percentage of us, around 1% of the total population, can’t carry out such exercises: these are the people living with aphantasia, a neurological condition that prevents the creation of conscious mental images. A scientific review has dug into our still-limited understanding of the characteristic, concluding that it is associated with reduced autobiographical memory and facial recognition. Also, that it is more common among autistic individuals and people in scientific professions.
Typically, our imagination hangs onto the sensory properties of objects and activities when they are absent, such as what the color orange looks like or the sound of thunder. Through an intricate neurological process, we are able to mentally call up these images. However, people with aphantasia are unable to build these internal images, to visualize them through thought. That doesn’t mean they have no imagination, qualifies Adam Zeman, professor at the University of Exeter and author of the aforementioned scientific review. “It indicates a lack of visual imagery and oftentimes, also sensory imagery, but people with aphantasia can be imaginative in the sense of creativity,” says the scientist, who published the article in the journal Trend in Cognitive Sciences.
First of all, it’s important to establish that aphantasia is not an illness. It’s more accurately classified as a characteristic that explains how an individual process information and that, “occasionally, can be a symptom of a neurological or psychological disorder,” says Zeman. A cerebral lesion or the evolution of a pathology can cause a loss of the ability to call up visual images in the mind, but the characteristic can also be hereditary and lifelong. The healthy people who experience it are completely functional.
In this sense, Saul Martínez-Horta, neuropsychologist at Barcelona’s Hospital Sant Pau who did not participate in the review, emphasizes that “normality in human cognition is diverse” and can function in very different ways. With aphantasia, he points out, “the way the neurological systems that process visual information are organized will probably be different,” but that doesn’t mean a person is incapacitated. “When something has always took place without any effect on our day-to-day life, that doesn’t mean much. But if something appears suddenly, like an inability to project images in the mind, that could be an indication that something has happened,” he says. Psychiatrists have reported the appearance of aphantasia in the context of depression, depersonalization and psychosis, among other conditions.
Zeman’s scientific review found that 1% of the population experiences pronounced aphantasia, but the spectrum is varied, and 2% to 6% of people were found to have “vague and tenuous” visual imagination. There’s also the other side of the coin, which is that around 3% of the population tends in the opposite direction and displays signs of hyperphantasia, the ability to generate hyperrealistic images in the mind. “There’s an entire spectrum of ability to evoke, but there is no standard value and it’s very difficult to quantify. Probably, it’s what one is born with,” says Javier Camiña, spokesperson for the Spanish Neurology Society, which did not participate in the investigation.
According to scientists, aphantasia is overrepresented among people who work in mathematics, computations and the sciences, a phenomenon that Martínez-Horta associates with convergent thinking. “In convergent thinking, when you consider the uses of a pen, your thoughts will be rigid and methodical: it is used for writing. On the other hand, divergent thinking is more childish: the pen can be a weapon or used to put up your hair. Aphantasia is associated with a convergent pattern, that is more bound by the predictable,” he says. In traditionally more creative industries, there is a greater likelihood of finding individuals with hyperphantasia.
Less autobiographical memory
When it comes to experimental memory measurements, people with aphantasia have also shown mild to moderate impairment. “Consistent with the close relationship between remembering the past and imagining the future, the richness of descriptions of imagined scenes is also reduced in aphantasia. Aphantasia similarly reduces the detail of eyewitness testimony,” Zeman points out in the article. Autobiographical memory, which refers to memory of a person’s own life, is also reduced among these individuals, to the point of being linked to a syndrome in which the individual lacks vivid first-person memories of his or her life history, even though he or she is able to function normally in day-to-day life.
Scientists are still trying to ascertain how a brain with aphantasia works. “The key difference probably lies in connectivity, with a stronger connection between the regions of thought and sensory areas among people who have more vivid mental images,” says Zeman. Camiña agrees that there likely are “differences in the modulation of certain processes” that play a role in the brain’s powers of perception. “In the absence of a stimulus, cerebral structures like the prefrontal cortex play a role; also, the limbic system, because we have to evoke past memories; and the fusiform gyrus, which is involved in facial recognition. Rather than structurally altered areas, there’s may be abnormal regulation of connectivity between these areas.
Indeed, another peculiarity of aphantasia is difficulty in recognizing faces: about 40% of people who experience this neurological feature say they have difficulties with facial recognition, more than twice as often as people who do not have the trait. The studies analyzed by Zeman also indicate that people with aphantasia score higher on questionnaires that measure the autistic spectrum.
Zeman also suggests that aphantasia “can offer certain protection against some mental health conditions,” because some studies have pointed to an elevated ability to create mental images as a risk factor for hallucinations caused by schizophrenia and Parkinson’s, as well as visual intrusions caused by post-traumatic stress. Still, the experts consulted for this article wanted to be prudent, and suggested that the issue is complex. “Likely, if that person has schizophrenia or Parkinson’s, they are going to have different hallucinations, possibly less symptoms. But it’s not the deciding factor. A person who starts out with hyperphantasia, if they suffer from post-traumatic stress, they will have the ability to recall a traumatic episode and it will show up with more frequency, intensity and duration of symptoms,” says Camiña.
Ability to dream
Paradoxically, although aphantasia prevents evoking conscious images, people with the neurological characteristic can dream. “This is probably explained by the fact that the path to the imagination in the brain is very different when it comes to voluntary imagination in a wakened state versus the imagination of dreams,” says Zeman. People with aphantasia are able to have dreams with visual qualities, although some studies describe avisual dreams “with variable narrative, textual, conceptual, auditory and emotional content” more frequently than among participants who do not have the characteristic, states the scientific review.
Experts admit that identifying aphantasia is complex because there are no infallible tests for its diagnosis and there is a high level of subjectivity in its perception. “Explaining how I see my internal world is very difficult. A person who has challenges in constructing internal images doesn’t know it. The majority discover what aphantasia is when they read about it somewhere,” points out Martínez-Horta. But that complexity doesn’t mean that it doesn’t exist or that everything is a product of our own perception. Zeman says that behavioral, physiological and neural data exists that unpacks differences in the aphantasia spectrum. He gives one such example in the article itself: “Whereas normal participants listening to (extremely) scary stories show a hike in their galvanic skin response (GSR) (they sweat!), people with aphantasia do not. The natural interpretation is that, in the absence of imagery, the impact of emotive language is reduced because imagery typically mediates between verbal description and emotional response.”
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