There Is A Very Simple Test To See If You Have Aphantasia

It's difficult to work out what is going on in your own mind, let alone anyone else's. That's one of the reasons why people with aphantasia, or who do not have an inner monologue (anendophasia), may not realize that their minds work differently from other people's.

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Aphantasia is a difference in the way the brain generates mental imagery. When the majority of people are asked to picture a horse, for example, they really do see a horse clearly in their mind's eye. You may see details of the horse you are picturing, its long, flowing mane, or its horrendous white sweat quite clearly. For around 1-4 percent of people worldwide, or around 82-380 million people on Earth, that is not the case.

"Aphantasia is the inability to voluntarily visualize mental images – a neurological variation that affects how people think, dream, remember, and learn. When someone with aphantasia tries to visualize an apple, a loved one's face, or a childhood memory, they experience no mental pictures," the Aphantasia Network explains.

"Instead of mental pictures, your mind works with facts, concepts, and knowledge. You know what a horse looks like – four legs, mane, tail – you just can't see one in your head."

Aphantasia is not considered a disorder or a disability, and you shouldn't worry if you have it. It's just a different way that the mind works. There is also some evidence that if you have it, with imagery training, your visual imagination and recall can be improved. But for the curious, in 2022, a team of researchers from UNSW Sydney developed a relatively simple test to see if people have aphantasia. 

For the small study, the team first recruited people who reported that they have a visual imagination, like the majority of the population. These 42 participants were then given glasses that would track their eye movements and pupil sizes as they were shown bright or dark shapes against a gray background. As expected, when exposed to bright shapes, the participants' pupils would constrict in response to the bright shapes, and dilate in response to the darker shapes, your eyes' normal response to these different stimuli. 

Next, the participants were asked to imagine those same shapes and report how vivid those images were in their minds. At the same time, the glasses tracked their eye movements and pupil response, and the researchers found that the participants' pupils dilated and constricted in response to the imagined imagery, sometimes as strongly as it had for the physical stimuli.

“The pupillary reflex is an adaption that optimises the amount of light hitting the retina,” Professor Joel Pearson, senior author of the paper, explained in a statement. “And while it was already known that imagined objects can evoke so-called ‘endogenous’ changes in pupil size, we were surprised to see more dramatic changes in those reporting more vivid imagery. This really is the first biological, objective test for imagery vividness.”

For the next part of the study, the team recruited 18 participants with self-reported aphantasia, or the lack of visual mental imagery. They were put through the same initial part of the test, and found to have usual pupil responses to the real stimuli (bright and dark shapes) placed in front of them. But when it came to picturing the bright and dark shapes without the physical stimulus in front of them, the team found that the aphantasia group's pupils did not significantly dilate or constrict in response.

“One of the problems with many existing methods to measure imagery is that they are subjective, that is to say they rely on people being able to accurately assess their own imagery. Our results show an exciting new objective method to measure visual imagery,” Pearson said, “and the first physiological evidence of aphantasia. With over 1.3 million Australians thought to have aphantasia, and 400 million more internationally, we are now close to an objective physiological test, like a blood test, to see if someone truly has it.”

While more research is needed, the results suggest that pupil response to imagined bright and dark stimuli could provide a good indication of whether you have aphantasia. In further tests, participants with aphantasia were found to have a pupil response when asked to imagine four objects at the same time, suggesting more mental effort, and that the first results were not down to non-participation by the group.

“Our pupils are known to get larger when we are doing a more difficult task,” Lachlan Kay, PhD candidate in the Future Minds Lab at UNSW, explained. “Imagining four objects simultaneously is more difficult than imagining just one. The pupils of those with aphantasia dilated when they imagined four shapes compared to one, but did not change based on whether the shapes were bright or dark. This indicated that the participants with aphantasia were indeed trying to imagine in this experiment, just not in a visual way.”

“The aphantasic pupil response to the four objects condition is also a really exciting finding,” Pearson added, “because for the first time we have strong biological evidence that those with aphantasia are really trying to create a mental image, putting to rest claims that they may simply not be attempting to create a mental image.”

While people with aphantasia may process mental imagery differently, that doesn't mean that they have problems with their memory. People without it may remember events and objects with imagery, but not having these vivid mental pictures does not necessarily mean a better memory.

“Our previous work has shown that aphantasic individuals are able to perform visual working memory tasks, remembering many images for a short period of time, without using visual imagery," Dr Rebecca Keogh, a co-author on the paper, added.

“These findings further highlight the wide variability of the human mind that can often remain hidden until we ask someone about their internal experiences or invent new ways to measure the mind. It reminds us that just because I remember or visualise something one way, doesn’t mean everyone does.”

The study is published in eLife.