Have you ever read a book and pictured the characters only to be baffled by their appearance in a movie? If you have aphantasia, chances are you would’ve found yourself thinking, “Oh, so that’s what they look like!” instead.
The term aphantasia was coined by Prof. Adam Zemen when he published his findings in 2015. The condition is described as an inability to conjure mental images of familiar faces, places and things. Phrases such as “paint a mental picture” were previously thought to be metaphorical to people who experienced aphantasia. Hyperphantasia, on the other end of the spectrum, is experienced by people who have a high degree of vividness in their mental images.
The Vividness of Visual Imagery Questionnaire (VVIQ) is one of the most popular methods to assess the level of mental imagery. Functional magnetic resonance imaging (fMRI) has been used to find the neural correlation with visual imagery vividness. fMRI measures participants’ brain activity by detecting changes associated with blood flow. In this technique, brain activity is measured during perception—in the presence of an external stimulus (an image) and then during imagination—once the stimulus is removed. The low vividness group showed activation in varied regions, whereas the high vividness group showed activation in fewer brain regions while imagining. There was no significant difference between the two groups during perception. This experiment leads us to believe that the lack of mental imagery is compensated for by other sensors. People with aphantasia often have a different strategy in their day to day lives, which may be why most don’t realize they’re missing something in the first place.
Aphantasia is primarily a self-diagnosed condition, found by taking questionnaires that may have subjective answers. Joel Pearson, professor of cognitive neuroscience at the University of New South Wales in Australia, conducted research to determine if poor metacognition was being mistaken as aphantasia. He used binocular rivalry, a test where different images are presented to each eye. All participants were asked to visualize one of the two images before it was shown to them. The high vividness group perceived the image that they had been asked to visualize before. This was not the case in the low vividness group.
Curiously, people with aphantasia do have visual dreams. They only have trouble voluntarily conjuring images. Autobiographical recollection and face recognition were also found to be challenging domains. They make use of knowledge and facts to arrive at conclusions that would generally require visual images. About 1% and 3% of the population are estimated to have aphantasia and hyperphantasia, respectively. These are by no means disorders, simply a different way of life. We all accomplish the same tasks but by using different mechanisms. People with aphantasia are drawn to scientific and mathematical domains, whereas people with hyperphantasia are drawn to creative professions, although there are exceptions. Various subtypes of aphantasia and hyperphantasia possibly exist, and further research could help us understand these conditions better.
-Suhana Nujum B20
Sources:
A life without mental images | BBC
When the mind’s eye is blind | Scientific American
Lives without imagery- Congenital aphantasia
The neural correlates of visual imagery vividness – An fMRI study and literature review
Behavioral and Neural Signatures of Visual Imagery Vividness Extremes: Aphantasia versus Hyperphantasia
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